The 3rd issue of the journal, Vol.2, N. 1, January-June 2013 ... - ISRM

CONTENTSPage No.From Editor’s Desk 2Articles• Role of Geology and Special Rock Mechanics Tests in TBM Tunnelling – A Perspective 4– V.M.S.R. Murthy and Anand Gautam• Influence of Anisotropic Stress Conditions on Design of Development Workings in Bord and Pillar Mining 16– R.K. Sinha, M. Jawed and S. Sengupta• Strata Monitoring Studies in Blasting Gallery Panel During Depillaring Based on Field Instrumentation 25– S. Kumar Reddy and V.R. SastryMr. Devendra K. Sharma assumes the charge of Managing Director 32of Himachal Pradesh Power Corpn. Ltd.Governing Council of Indian National Group of ISRM for the Term 2011-2014 33Recent Activities of Indian National Group of ISRMIndian national Group of ISRMISRM (India) JournalVolume 2, No. 1 January 2013• Seminar on “Ground Control and Improvement”, 20-21 September 2012, New Delhi 34• International Seminar on “Minimizing Geological Uncertainties and Their Effect on 35Hydroelectric Projects”, 27-28 September 2012, New Delhi• Seminar on “Slope Stabilization Challenges in Infrastructure Projects”, 3829-30 November 2012, New DelhiISRM News 41News from Indian National Group of ISRM 47Publications of Indian National Group 48Guidelines for Authors 49Forthcoming Activities of Indian National Group of ISRM 51Editor• Mr. V.K. Kanjlia, Member Secretary, ISRM and Secretary, Central Board of Irrigation and Power (CBIP)Associate Editors• Mr. A.C. Gupta, Treasurer, ISRM and Director, Central Board of Irrigation and Power (CBIP)• Mr. Uday Chander, Senior Manager, Central Board of Irrigation and Power (CBIP)All communications to be addressed to :The Member SecretaryIndian National Group of ISRMCBIP Building, Malcha Marg, Chanakyapuri, New Delhi – 110 021Subscription Information 2013/ (2 issues)Institutional subscription (Print & Online)Institutional subscription (Online only)Institutional subscription (Print Only): Rs. 900/US$75: Rs. 600/US$50: Rs. 600/US$50

ISRM (India) JournalFrom the Editor’s DeskFirst of all, I take this opportunity to wish all the readers a Very Happy and ProsperousNew Year.Considerable activities in India in the field of rock mechanics are in progress, mainlydue to the execution of projects for water resources development for irrigation, floodcontrol and hydro power generation, building of roads in mountainous areas, sub-surfaceexcavations for under-ground railway, storage and mining purposes, etc.Constructions of dams, tunnels, underground works, open pit mining, deep undergroundmining, rock slope stability are the works necessitated for the aforesaid structures.Development of these structures often encounter problems associated with unfavourablegeological conditions. How these problems have been dealt successfully is what we should all share. Theexperience gained during construction of these works will help in understanding the mechanism or rocksupport interaction, thus advancing the frontiers of rock mechanics.From the year 2013, Indian National Group has planned an International Symposium on “Rock Mechanics”every year to deliberate on the advances in rock engineering. The first event under the series “RockMechanics India’2013- Present Technology and Future Challenges” will be held in August 2013 in NewDelhi. I hope that the deliberations at the symposium will help in formulating appropriate measures neededfor successful execution of projects whether they relate to mining, tunnelling, underground cavern or metro.I invite all concerned to actively participate in the Symposium.I thank all the authors for their contributions to this issue. I thank the members of the Editorial Board forsparing their valuable time to review the papers and offer their comments/suggestions to improve thecontents of the articles.The fee back from all the quarters has given us the encouragement to our initiative and I request all thereaders and their colleagues/fellow professionals to contribute technical papers/case studies to furtherimprove the utility of the Journal.V.K. KanjliaEditor and Member SecretaryIndian National Group of ISRMVolume 2 No. 1 January 2013

Influence of Anisotropic Stress Conditions on Design of Development Workings in Bord and Pillar MiningMESSAGE3At the outset, as President of the International Society for Rock Mechanics (India),I would like to convey my Hearty Greetings and Best Wishes for a very Healthy, Happy,Prosperous and Successful New Year – 2013 to all the Members of the ISRM (India)and all Subscribers/ Readers of the ISRM (India) Journal. I would also like to conveymy Greetings and High Appreciation to all the Members of the Editorial Board.Rock Mechanics is the theoretical and the applied science of the mechanical behaviour ofRock and Rock Masses. The present state of knowledge permits only limited correlationsbetween theoretical predictions and empirical results. The most useful principles arebased upon data obtained from laboratory and in-situ measurements and prototype behaviour. RockMechanics is one of the main fields of interest in Hydro Power Development, Infrastructure Development,Mining etc. Rock Mechanics is becoming increasingly important in many more branches, the most significantglobally being the disposal of hazardous radioactive waste in deeply located repositories. It is an interdisciplinaryengineering science requiring interaction between the Physics, Mathematics, Geology, Civil,Petroleum and Mining Engineering. Collaboration among disciplines offers the best hope for success indealing with the present and future problems related to Rock Mechanics. Our Editorial Board is designedto include researchers with inter-disciplinary expertise at International level in addition to researchers withexpertise in the relevant disciplines.The main aim of the Journal is to disseminate the development of techniques, new trends, experiencegained by others to enable updating the knowledge of Rock Mechanics.The Journal is published Half Yearly and available in both print and online versions The First Issue of theHalf Yearly Technical Journal ISRM (India) was brought out in January 2012. The quality of contents andprinting has been very good. However, there is always a scope to improve and excel.I would request all the readers to offer their valuable comments and suggestions to enable us to improvethe quality and the utility of the Journal.Dr. H R SharmaPresident, ISRM (India)&Chief Technical Principal – HydroTractebel Engineering Pvt. Ltd.Volume 2 No. 1 January 2013

4 ISRM (India) JournalROLE OF GEOLOGY AND SPECIAL ROCK MECHANICSTESTS IN TBM TUNNELLING – A PERSPECTIVEV.M.S.R.Murthy and Anand GautamDepartment of Mining Engineering, Indian School of MinesABSTRACTA growing need to switch over to the clean sources of energy, such as hydropower, is being feltin India after burning much of our coal reserves to an alarming stage. Incidentally, India has beengifted with numerous perennial rivers originating from the great Himalayas favoring hydropowergeneration. However, these young folded mountains with an extremely variant geology createdseveral problematic situations delaying many tunnelling projects.The major construction work of any hydro power project is the construction of head race tunnel(HRT) which had made use tunnel boring machine popularly known as TBM. There are numberof ongoing projects of NHPC Ltd and NTPC Ltd such as Parbati Stage II and Tapovan-Vishnugadprojct, etc. deploying TBMs for tunnelling. As huge amount of money is involved in deploying TBM,it is important that it should successfully complete the project. Thus, suitability of TBM needs to beestablished with the help of various geological and geophysical investigations coupled with insituand laboratory tests. The role of geology, uncertainities involved and consequent hazards have animmense influence on the operational success of TBM and hence need attention.TBM performance prediction models, namely, NTH, CSM, RMi-NTH & QTBM, are frequently usedowing to their increased popularity over the years. RMi- NTH model is an empirical performanceprediction method based on historical field performance of machine in certain rock types. Empiricalgraphs and equations obtained from regression analysis between rock properties, ground condition,machine parameters and rate of penetration are used in this. The CSM model on the other handinvolves starting from the individual cutter forces and determines the overall thrust, torque and powerrequirement of the entire cutter head.This paper discusses the geological problems encountered while driving tunnels with TBM, specially,with respect to Indian conditions. Different types of specialized rock mechanics tests that are carriedout and available at Indian School of Mines, Dhanbad for enabling the selection of TBMs are alsopresented alongwith some results. Typical performance achievable in a given rock type is estimatedusing the RMi-NTH model. A case study of TBM drivage pertaining to Tapovan-Vishnugad Hydelproject, NTPC Ltd. is considered for the analysis. The suggested approach with field corroborationcould be useful for predicting the possible advance rate in a given formation.Keywords: Geological problems, mixed face conditions, rock mechanics tests, tunnel boring machine,head race tunnel, boreability prediction models1. INTRODUCTIONIndia has an immense hydropower potential to the tune of84000 MW, a major chunk of which is in Himalayas. Thesurge in power demand in the country has necessitatedputting an increased thrust in development of hydroelectricprojects in India. The pace of tunnelling work, which formsa major component of hydroelectric development, hasa notable bearing on the implementation of the project.Now while the focus is on faster completion of projects,need for advanced technology like TBM in tunnelling isrequired. But unfortunately TBM could not gain wideracceptance in the country due to complexities involvedin geological conditions, prevalent in India especially inHimalayas. The tectonically deformed jointed rock massof Himalaya pose a major challenge to project planners.Although initial experience with TBM was not encouragingall efforts are on to make TBM successful in India.Though TBM excavation is a very fast method tunnelling,it needs meticulous planning because in case ofunpredicted/unfavourable conditions, the adverse effectsof TBM in terms of time and cost are far more greater thanconventional methods thus putting a huge investment atVolume 2 No. 1 January 2013 4

Role of Geology and Special Rock Mechanics Tests in TBM Tunnelling – A Perspective5risk. The experience suggests that many of the problemscan be avoided if sufficient advance information aheadof the face is available. It is essential that detailedexploration work is carried out before the start of theproject and exploration ahead of the face should beundertaken on a condition basis. Use of tunnel seismicprofiler services can be roped in for predicting in advancethe geological condition to be encountered (upto 200 mfrom the face).The choice of TBM is another important aspect thatneeds an initial analysis at planning stage and no TBMcan be designed for every type of geological conditionthat is encountered in tunnelling though due care canbe exercised in minimising the operational problemswith adequate rock testing programs both in laboratoryand field. Thus, the design and special constructioncharacteristics of each TBM need to be carefully designedproject-specific for the successful completion in time.The concept of tunnel boring machines is not new andits history dates back to the year 1846 in Italy. Sincethen there have been revolutionary improvements in thismachine. Though it has completed many challengingprojects in the field of road/railway tunnels, hydro powerand different other utilities successfully but there are anumber of cases where it has been proved to be a curseduring the middle of the project. The TBM had got stuckin the mid way of the project due to various reasons,chiefly resulting from the varying geology of the stipulatedproject area, and thus creating huge financial losses to thecontractor as well as undue delays in the project. India isbestowed with huge hydropower potential chiefly spreadacross Himalayas. Some of the TBM projects envisagedor already deploying TBMs are given in Table 1.Table 1 : TBM projects envisaged in India (Dubey, 2008)Hydro power projectsPowergeneratedStatus of projectChenab Basin (HP) 2500 MW IdentifiedTapovan vishnugad 520 MW Under implementationRupsiabagar Khasiabara 261 MW Under clearanceAmochu (Bhutan) 500 MW IdentifiedKolodyne (Mizoram) 460 MW IdentifiedEtalin & Attunli(AP) 4500 MW Identified2. ROLE OF GEOLOGY IN TBM DEPLOYMENT“For the geologist, the range of rock conditions is like aparadise but for the contractor, it is a nightmare,” by V. L.“Raja” Rajasekaran.The geology along a tunnel alignment plays a dominantrole in many of the major decisions that must be made inplanning, designing, and constructing a tunnel. Geologydominates the feasibility, behaviour, and cost of anytunnel. Although difficult to appreciate, the engineeringproperties of the geologic medium and the variations ofthese properties are as important as the properties of theconcrete or steel used to construct the tunnel structure.In a tunnel, the ground acts not only as the loadingmechanism, but also as the primary supporting medium.Thus, it is vital that the most appropriate geotechnicalinvestigation is conducted early in the planning process forany tunnel. The more challenging the ground, the greaterthe pre-planning that is required before tunneling.Some of the difficult ground conditions, which can affectTBM performance, are boreability limits, instability of theexcavation walls, instability of the excavation face, faultzones and squeezing. Tunnel excavation by a TBM mayencounter other difficult ground conditions as well dueto the presence of clayey soil, soft ground resulting insettlement of the TBM, strong inflow of groundwater andgas, rock bursting, rock and water at high temperatureand karstic cavities.It has been shown many times that those tunnels thathave been investigated more thoroughly have fewer costoverruns and fewer disputes during construction. Theunanticipated problems are those that can create costlydelays and disputes during tunnel construction. Detailedand thorough explorations must precede any tunnelingactivity more so in case of TBM technology so that theycan help evaluate the feasibility, safety, design, andeconomics of a tunnel project.2.1 Geological Uncertainties – Their Influence onExcavation by TBMs in IndiaUncertainty means “lack of knowledge”. But still in manycases this problem may be resolved substantially by themethods of quantification or some other methods in whichwe can derive some useful information and reach to adecision. Uncertainty may be categorized in two ways,1. Aleatoric Uncertainty (natural variability)2. Epistemic (uncertainty due to ignorance)The former refers to the distribution in the parametersthat influence the behavior of the structure. This type ofuncertainty cannot be reduced by extended measurement.The second type of uncertainty can be attributed to lackof knowledge. This includes insufficient knowledge ofthe actual geological condition including poor conditionin terms of properties and geometries. This type ofuncertainty can be reduced by obtaining more information,i.e, from investigation, monitoring and measurements(Palmstrom, 2010).2.2 Reasons for Poor TBM Performance in Tunnelling –Some Geological IssuesIn Indian scenario, it may be observed that almostall the hydro power projects are situated in themountainous region i.e., Himalayas or sub-Himalayantracts. Himalayas, being young folded mountains, arestill undergoing changes and are subjected to intenseVolume 2 No. 1 January 2013

6 ISRM (India) Journalcompression primarily due to continent-continentcollision. This often resulted in numerous folds,faults, foliations and joints which are the commoncharacteristic of these rocks raising stability concerns.The previous studies on TBM applications in India byVishnoi in the year 2012 have revealed useful factspertaining to the uncertainties found in the projectsand the outcome (Table 2).In a nut shell, the following are some of the prime causesof poor tunnelling rates achieved by TBMs in India:• Intensely disturbed grounds• Water seepage under high pressure leading toinstability• Supporting problems in shear zones sometimesassociated with intense water ingress• Squeezing ground• Release of rock blocks due to blocky and jointedstrata• Rock bursts due to cover loads• High geothermal gradients• Cavity formation• Hard and abrasive rocks leading to higher cutterconsumptionDeploying a TBM for a project involves a huge investmentand risk from the employer as well as contractors side.The unfavourable conditions can be produced by eithera rock mass of very poor quality causing instability of thetunnel or a rock mass of very good quality (i.e. strong andmassive rock mass) leading to very low penetration rates.Typical hazards associated alongwith the probability ofoccurrence and risk allocation are presented in Table 3.Some of the hazards associated with the TBM tunnellingare more frequent and thus need special attention apartfrom their allocation weather it is to the employer or thecontractor.Table 2 : TBM applications in India and the uncertainties encountered (Vishnoi, 2012)Project Location Uncertainties OutcomeDulhasti Hydro Electric Project,NHPC Ltd.Lesser Himalayas in Kishtwardistrict of Jammu & Kashmir,India• Unfavourable geologicalconditions in the form ofshear zones crossing thetunnel regularly with highseepages of water andincidences of roof collapse.• Tunnel’s structural failureduring construction.• TBM got buried.• Contractual complicationsContractor refused tocontinue• High cost and time overrunKoteshwar Hydro ElectricProject, THDCParbati Stage II Hydro ElectricProject, NHPC Ltd.Middle Himalayas inUttarakhand State, India.Located in Kullu district ofHimachal Pradesh, India• Unfavourable geologicalconditions in the form ofslope failure at powerhouse location duringconstruction.• Major flood occurred at siteduring construction.• Diversion tunnel’s structuralfailure during construction.• Contract rates becameunviable.• Unfavourable geologicalconditions in the form oflarge underground waterinflows.• TBM got buried• Contractor started lookingfor claims rather thancompleting the works.• Proactive action by theOwner• Contractor was not ready toshare the unexpected Risk.• Inordinate delay incompletion.Tapovan- Vishnugad HydroElectric Project, NTPC Ltd.Uttarakhand, India.• Excessive cutter wear due toabrasive rocks,• Unfavourable geologicalconditions in the form ofheavy water ingress due tofault/ geological failures.• Contractor stopped the workand denied accepting thecost of risk.• Delayed constructionVolume 2 No. 1 January 2013

Role of Geology and Special Rock Mechanics Tests in TBM Tunnelling – A Perspective7Table 3 : Typical hazards associated with TBM tunneling with relative probability of occurrenceHazard Probability of Occurrence Risk AllocationHigh water pressure Medium EmployerSwelling pressure Medium EmployerStucking, clamping of TBM Medium ContractorFace collapse by ground water flow Medium ContractorGas detection Medium ContractorOverstressed lining by ground water pressure Low ContractorExcavation material not transportable through conveyor belt Medium ContractorExceptional high wearing of excavation tools High ContractorBoulders within soil formation Medium ContractorNatural Caverns Medium EmployerApproaching fault zone High ContractorWater inflow through segments Medium ContractorContaminated ground Very Low ContractorTreatment of excavation material Very low ContractorThermal Impact High Contractor2.3 Boreability Using TBMsThe TBM performance basically depends on the threevariables, namely, penetration rate, machine utilizationand cutter cost. The main index describing the capacityof a TBM to excavate a given rock is the penetrationrate per revolution of the cutter head that the TBM isable to achieve under the maximum thrust. It is notpossible to establish a limit of penetration per revolutionbelow which a rock shall be considered non-boreable.Such a limit is also influenced by the abrasivity of therock, the diameter of the tunnel, and the thickness ofthe rock formation. The high abrasivity, associatedwith low penetration, dictates frequent changes ofcutters, increasing the cost for each cubic meter of rockexcavated, in addition to the time lost in substituting thecutters. With increase in the tunnel diameter there aredifferent effects which make the situation worse. It may,thus, be summarized that large variability in geology isthe root cause of the problems leading to delays andelevated costs. Thus, considerable effort should begiven at the initial stages of the project for conductingcomprehensive and proper site investigation as the costof such investigation is relatively low in comparisonwith the total contract sum. As for budgeting ITArecommends 2.5% to 3% of the estimated total contractvalue should spent on investigations2.4 Mixed Face Conditions (MFC) and their Effect onTBM PerformanceHard rock tunnel boring machines (TBMs) have todayreached a stage of development so that a tunnel canbe bored in practically any rock mass. However certainground conditions still present considerable challengesfor the economic application of the TBM method. “ Mixedface conditions”, shortened as MFC, is a term used whenthe tunnel face consists of atleast two rock types withcompletely different boreability – in simple terms a mixof soft and hard rock. It is a normal feature in hard rocktunnels. It causes well known problems with impactsto the cutters and increased loads to the cutter headstructure and main bearing. An easily observable resultis increased vibration. This result in reduced penetrationrate, increased cutter breakage and other delays reducethe TBM utilisation. The effect of overall performancemay be significant, especially if the MFC are pronouncedand prevails over long tunnel section. Failure to predict orrecognise MFC may cause selection of not suitable TBMsresulting in seriously reduced performance, which may leadto contractual claims (Blindheim and Nilsen, 2002).The degree of MFC depends on both the mechanicalproperties of the geological formations and the geometryof such formations. In a horizontal tunnel a vertical dykecrossing the tunnel perpendicularly will normally not givemuch problems. As the geological formations are alignedmore parallel o the tunnel axis, the situation becomesincreasingly unfavourable. This is the case for instance inIcelandic basalt formations, as shown in Figure 1, wherethe different volcanic and sedimentary layers are usuallydipping 2°-10°.It is evident that a large part of a near horizontal tunnelin such geological conditions would be excavated inMFC. This could affect the boreability of the rock andVolume 2 No. 1 January 2013

8 ISRM (India) Journalimmediate reaction will be to lower the applied thrustforce to the cutter heads and to reduce the RPM. Towhich level the thrust and RPM should be reduced isinfluenced by many factors such as boreability of therock and rock mass, the size of cutters, the type and ageof the TBM, the length and expected conditions on theremaining drive, etc.2.4.3 Dealing with MFCFig. 1 : Mixed faced conditions often encountered in TBMtunnelling (Blindheim and Nilsen, 2002)stability of the face. For explaining this several physicaland mechanical parameters that are expressing theboreability may be relevant for describing MFC. For thisUniaxial compressive strength (UCS) is the parameter thatoften is put in focus in discussions concerning MFC. TheUCS may not be the best parameter for TBM boreability,but its availability makes it a useful reference. Nextparameter that used is Drilling Rate Index (DRI) may bemore relevant as it includes the resistance to impacts,which simulates the dynamic loading of rock from the disccutters. Further parameters include elasticity or abrasivitymay also be of relevance to describe MFC.2.4.1 Effects of MFCThe effects of MFC with respect to boreability areconnected to impacts on the cutters, vibrations of thecutterhead and the TBM, uneven loading of the mainbearing, and increased cutter breakage. The disc cuttersexperience a rapidly varying load from close to zero to peakloads of 5-10 times the average. If this hardness variationis sharp between two rocks, the cutter will experience animpact, rolling from the weaker into the stronger material,the average and peak loads also jump up to a higher level.If this impact is large, the cutter edges may chip or break.If the rocks are abrasive, the abrasive wear may alsoresult as the contact stresses are increasing. Over time,the cutter bearings will take more and higher shock loadsper revolution, and bearing breakage will occur moreoften. And if the bearing “freezes”, the cutter ring will bedestroyed as well. In total increased cutter consumptionwill result. The effect is TBM utilisation is reduced due toincreased cutter change time, as well as increase of otherscheduled and unscheduled stoppages.2.4.2 Effects on TBM OperationDuring operation of TBM if operator observes that thevibrations are increasing from the normal level to highlevel or if the TBM deviates due to uneven hardness hisMFC with different rock types would normally have lessimpact than a medium to very fractured rock mass. Infractured rocks, the rocks may fall out or pushed out offace leaving open gaps or voids. The voids left in theface will cause impacts when the cutters passing thevoids hits the rock on the side of the void. In MFC caseswith very high strength ratios say above 5-10, it may benecessary to reduce by 50%. This would obviously havea large impact on the overall performance.2.5 Models for Predicting the TBM PerformanceTwo popular approaches for the calculation of TBMpenetration are available though a few models arerecently added to this. The most popular models areCSM and RMi-NTH models. Input in the form of rockcharacterstics and machine parameters are providedand after numerous computations the output in the formof certain useful performance parameters is provided(Table 4).3. ROCK MECHANICS TESTS vis-a-vis TBMSELECTIONIt may be observed from the above-mentioned two TBMperformance prediction models (Table 4) that several rockparameters are needed to be used as input parameters forthe introduction of TBMs which are essentially obtainedfrom both laboratory and field investigations. Consideringthis need relevant test setup was created at Indian Schoolof Mines, Dhanbad and tests are being carried out since2001. The following sections present the rock mechanicstests required to be carried out for TBM selection, designand operation (Murthy et al, 2005).• Brittleness Index (BI)The brittleness value S 20is an indirect expression ofthe necessary amount of energy it takes to crush therock. About 500 gm crushed rock sample(based on thedensity of rock) between 16 and 11.2 mm sieve size istaken and pounded with a 14 kg weight from a heightof 25 cm for 20 times. The BI value is the percentageof the material that passes the 11.2 mm sieve after20 drops and is determined as the mean value of 3to 4 parallel tests. Higher the brittleness better is therelative boreability.Volume 2 No. 1 January 2013

Role of Geology and Special Rock Mechanics Tests in TBM Tunnelling – A Perspective9Table 4 : Parameters used in CSM and NTH models for TBM design (Palmström, A.1995, Bruland 1998)CSM MODELRMi-NTH MODELParameters units Parameters unitsINPUTCutter radius (in) Fracturing Class(0-iv)Tip width (in) Brittleness S20 IndexSpacing (in) Drillability Sievers ‘J indexPenetration (in) Abrasiveness AV indexRock UCS (psi) Porosity %Tensile Strength (psi) Cutter Dia mmTBM Diameter (ft) Cutter Load kNRPM (rev/min) Spacing mmNo. of Cutters (#) Machine Diameter mOUTPUTThrust(lbs)Torque(ft-lbs)Power(hp)Cutting Force (lbs) No. of Cutters #Normal- Thrust (lbs) RPM rev/minRolling/Torque (lbs/ft-lbs) Thrust TonPower (hp) Power kWBasic Penetration (in/rev) Basic Penetration mm/HrRate of Penetration (ft/hr) Rate of Penetration m/HrHead Balance (force/moments) Torque (kN-m)Machine Specification (th,tq,hp,etc) Utilization %Performance Curve (Graph(rop-vs-th tq vs ts) Advance Rate (m/Day)Utilization Curve (%) Cutter life (Hr/Cutter)Advance rate(Ft/day)Cutter life(Hr/cutter)• Sj ValueThe Seiver’s J value expresses indirectly the surfacehardness of the rock. The hole depth measured in 10 -1mm units after 200 revolution by the miniature drill withthrust of 20 kg is known as Sj value. The drill bit usedis 8.5 mm in width with 110 g bevel angle. Higher the Sjvalue better is the boreability.• Drilling Rate IndexThe DRI values are obtained using a nomogram shownin Figure 3.d. Higher the DRI better is the boreability.• Cerchar Abrasivity IndexAbrasiveness is one of the properties of rocks thatis measured in order to assess their suitability formechanical excavation. This parameter has been found tostrongly govern the performance of disc cutters, their rateof replacement and therefore the cost of the tunneling.The test is conducted by abrading a steel pin under astatic load of 7 kg by moving the pin 1 cm on the rock in1 sec. The pin is machined from steel having a tensilestrength of 2 kN/mm 2 (Rockwell hardness 54-56). Thepin is shaped to have a sharp 90 0 conical point. Aftereach abrasion test the wear flat on the end of the pin ismeasured using a microscope equipped with a lengthscale. The average diameter of the wear flat, measured in10 -1 mm units gives the The Cerchar Abrasivity Index. Thescale ranges from 0 to 6, one-index point correspondingto a conic blunt surface diameter of 0.1 mm. Rocks withan abrasiveness value greater than 4 may give rise tohigh rates of wear on TBM cutters.• Uniaxial Compressive StrengthThe uniaxial compressive strength of rock samples isdetermined using a stiff testing machine (servo controlled)under controlled loading rate. Tests are carried out asper the norms laid down for testing in ISRM suggestedmethods.Volume 2 No. 1 January 2013

10 ISRM (India) Journal• Brazilian Tensile StrengthThe tensile strength of rock is determined using Brazilianmethod. Both parallel and perpendicular to foliation aredetermined so as to fix the cutters to take this advantage.Values are higher when the samples are loadedperpendicular to foliations.• Young’s Modulus of Elasticity & Poisson’s RatioThe Young’s Modulus of elasticity (tangent) wasmeasured in MTS stiff testing machine using straingauges (balanced). The data were acquired by a dataacquisition system (SPIDER 8).• Thin section analysisMineralogical studies were also done to understand thehard minerals present alongwith their texture, orientationetc. Microphotographs of two rock types are shown inFigure 2 a & 2b.3.1 Summary of Laboratory InvestigationsOf the seven rock types tested, the quartzite rockshave the lowest DRI value (52). Metabasic Rock andMica Schist have the highest DRI value, i.e., more than79. Low DRI values indicate difficult boreability for theTunnel Boring Machine, in general, where as higherDRI values indicate easier boreability. The CercharAbrasivity Index (CAI) for the Quartzite rock was foundto be 5.62 which indicates that there will be high rate ofwear in TBM cutters when compared to other rock typesmentioned above. Higher abrasivity of quartzite andcoarse-grained gneiss, weak strength of metabasic rockare some of the typical observations in these rock suits.The Young’s Modulus of elasticity was the highest forquartzite (55.5 GPa) and the lowest for the metabasicrocks (7.8 GPa).Fig. 2a : Thin Section of Metabsic rockFig. 2b : Thin Section of QuartziteDifferent test setup and the results on different rock suits supplied from Tapovan-Vishnugad project are provided inFigure 3 and Table 5 respectively.Table 5 : Rock properties of different rock suits, Tapovan-Vishnugad Hydel Project (Murthy, 2005)Name of rock BI Sj DRI CAI UCS (MPa) BTS (MPa) MOE (GPa) Poisson’s RatioMetabasic rock 69.5 53.2 79 2.40 84 (52-107) 6.7-8.3 7.8(5.8-9.5)Augen Gneiss 52.4 31 58 3.42 91 (61-125) 8.4-8.7 27.9(24-29)0.26(0.16-0.33)0.23(0.18-0.30)Coarse grained Gneiss 63.2 28.6 69 4.35 77 (63-88) 7.3-7.9 35 (23-48) 0.27(0.10-0.40)Foliated Gneiss 63.5 5.5 62 3.50 98 (84-114) 7.3-10.1 36.7(34-40)Fine grained Gneiss 58.7 16 61 3.00 196(143-236)Quartzite 55.6 3.83 52 5.62 184(103-254)6.9-8.4 36.1(29-42)7.8-8.7 55.5(45-63)Mica Schist 70.3 107.5 86 2.28 Regular core sample could not be obtained0.24(0.17-0.34)0.14(0.11-0.16)016(0.15-0.18)Volume 2 No. 1 January 2013

Role of Geology and Special Rock Mechanics Tests in TBM Tunnelling – A Perspective11(a) Siever’s J value (Sj)(b) Brittleness index(BI)(c) Cerchar Abrasivity Index (CAI)(d) Nomogram for estimation of DRI(e) Uniaxial Compresssive strength(f) Brazilian Tensile Strength(g) Setup for the determination of Young Modulus(h) Analysis for computing MOE and Poisson’s RatioFig. 3 : Laboratory test setup for TBM application, ISM, DhanbadVolume 2 No. 1 January 2013

12 ISRM (India) Journal4. PERFORMANCE PREDICTION OF TBMTBM is in operation in Tapovan-Vishnugad Hydel Projectof NTPC Ltd. The TBM adit between Ch. 130.00 and371.08 m was excavated by a double shielded tunnelboringmachine (Figure 4). The rock mass was observedfrom the muck either on the conveyor belt or in thedumping yard, through the holes for pea gravel, groutingand erector in the precast segments, in front of the cutterhead and through the telescopic shield. The rock massin TBM adit are predominantly quartz mica gneiss withmica schist and quartzite bands, and quartzite (JoshimathFormation), which are highly to slightly weathered and /or disintegrated (Weathering grade: W3 to W1).The rock mass is characterized by prominent two or morejoint sets and few random joints with silty or sandy-claycoatings and small clay fraction (non-softening), andnon-softening minerals, sandy particles, and clay-freedisintegrated rocks, etc. along them. The rock massis completely dry in general and wet at some places.Judging from the total thrust force of the cylinders, whichlies mostly below 5000 kN, the rock mass conditionappears to be poor to fair. Based on the estimatedQ-values, permanent rock support (a combination of rockbolts, steel fiber reinforced shotcrete and steel ribs) wasrecommended for HRT. (Adhikari et al., 2009).Table 6 : TBM specifications used in Tapovan-VishnugadHydel Project, NTPC Ltd. (S.K. Sengupta, 2008)ModelMachine parametersFront shield diaCutter headDisc cutters(54 nos)Max thrust per cutter ringMax recommended cutterheadthrustCutter head powerMax torqueGripping force by grippers(2nos)Cutter Tip width4.1 Estimation of Penetration RateValueHerrenknecht’s double shieldhard rock TBM6480 mm6550 mm432 mm(17”)267 kN14,418 kN6x350 KW4590 kNm2x18465 kN19.05 mmThe basic penetration can be estimated, for a given grossthrust per disc and cutter diameter, from the study conductedby Movinkel & Johannessen in1986 (Figure 5).Fig. 4 : Layout of the HRT, Tapovan-Vishnugad HydelProject, NTPC Ltd.(Murthy, 2005)The headrace tunnel driven using TBM at Tapovan-Vishnugad Hydro Power Project would intersect, mainly,medium to high grade metamorphic rocks. The projectarea forming a part of Dhauliganga and Alakhnanda valleyexposes rock classed as central Himalayan crystalline.The tunnel is proposed to be driven by Tunnel boringmachine (TBM.) to negotiate the high cover reach. Thelength of the tunnel to be bored by TBM from Dhauligangato Alakhnanda would be around 11.975 kms, and likelyto cover Metabasic rock, Augen Gneiss, Coarse grainedGneiss, Foliated Gneiss, Fine Grained Gneiss, Quartziteand Mica schist formations throughout its length. The TBMspecifications used are provided in Table 6.Fig. 5 : Basic penetration as a function of DRI, (fromMovinkel and Johannessen, 1986)From the above suggested method, for a DRI value of52 and gross thrust per cutter at 210 kN, the penetrationcan be found as 5.32 mm/rev. For a thrust of 267 kN(for the TBM being used in Tapovan), this could wellbe extrapolated close to 9 mm/rev. Considering thelimitation of the above approach for higher thrust values,the RMi-NTH model has been used for estimating thebasic penetration.The RMi-NTH model, for estimating the daily advance ofTBM for HRT driven in Parbati Stage II TBM tunneling,was presented earlier (Murthy et al, 2011). According tothe RMi-NTH Model, the instantaneous penetration rateis given by the following relation, and the unit is mm perrevolution.Volume 2 No. 1 January 2013

Role of Geology and Special Rock Mechanics Tests in TBM Tunnelling – A Perspective13I o= (M EQ/M 1) b ...(1)where, M EQrepresents the TBM properties, and ‘M 1’ and‘b’ depends on the rock mass properties. The rock massproperties are in turn represented by the factor ‘K EQ’.The value of ‘M EQ’ and ‘K EQ’ can be determined by therelations (equation 2 & 3) given below:M EQ= M Bx K Dx K A=267*1.15*1.02=313.2 kN ...(2)K EQ= K Sx K DRIx K POR= 1.0*1.04*1.02=1.06 ...(3)Where,M Bis applied thrust per disc (in kN),K Dis the correction factor for cutter diameter, (refer Fig. 6)K Ais the correction factor for cutter spacing, (refer Fig. 7)K PORis the correction factor for Porosity.(refer Fig. 8)K DRIis the correction factor for DRI, (refer Fig. 9)K Sis the correction factor for jointing/fractures, (refer Fig. 10)M 1and b values for obtained K EQvalues are obtained fromFigure 11 and Figure 12.The penetration rate is calculated using the relation (1)as follows:I o= (M EQ/M 1) b = (313/80) 1.7 = 10.16 mm/revThe net advance rate (m/h) is found from relation (4):I = (I O) x (RPM) x 60/1000 = 10.16*4*60/1000= 2.44 m/h ...(4)Daily Advance (D A)=(I) x (W) x (U) = 2.44*12*0.4= 11.7 ...(5)Where,I Ois the instantaneous penetration rate (mm/rev).RPM is rotation per minute.W is working hours available per day (two shifts with 6hours at face)U is the utilization factor (%)D Ais advance per day (m/day)Fig. 6 Fig. 7Fig. 8 Fig. 9Volume 2 No. 1 January 2013

14 ISRM (India) JournalFig. 10Fig. 11 Fig. 12RMi-NTH Model5. CONCLUSIONFeasibility of a TBM is very much based on the abilityof TBM and its other back up equipment to performefficiently under the averages obtained from the differentlab and field investigations defining the favorable orthe adverse geological condition. Previous tunnellingexperience in India has proved that geology has oftenplayed a decisive role in deciding the success or failureof the project. TBMs to be used for tunnelling in hardrock terrain have to be designed and selected to beable to sustain mixed faced conditions (MFC) also.Thus, it is very important that planning, design andpreparation of contract documents take the responsibilityof MFC into consideration apart from the variations inrock properties. All the TBM drivages must take intocognizance the variations in geology and this canbe best achieved through a careful sample selectionfollowed by a comprehensive testing programme.This data will be immensely useful in designing theTBM systems may it be using NTH or CSM or Q TBMorRMi-NTH methods. Specialised tests, namely, DRI,CAI and Brittleness were found to relate reasonablywell with the penetration rate achieved. Thin sectionanalysis and identification of microstructure has alsohelped understand the reasons for poor boreability andhigher cutter rate consumption. Physico-mechanicalproperties help in designing the overall system. Testdata generated for Tapovan-Vishnugad Hydel Project byISM has been utilized to estimate the basic penetrationrate with RMi-NTH model. This can be used, rock suitwise,for arriving at the daily advance (assuming suitableutilization of machine). Considering the established utilityof lab tests, it is needless to re-emphasize the need forextensive laboratory studies during planning stage oftunnelling with TBM. However, the predicted penetrationrates in different rock suits need to be correlated withVolume 2 No. 1 January 2013

Role of Geology and Special Rock Mechanics Tests in TBM Tunnelling – A Perspective15actual penetration achieved in the field for the betterappreciation of the entire process and develop usefulguidelines in Indian scenario as TBM tunnelling is goingto catch up further.Acknowledgement – Authors thankfully acknowledgeall the concerned officers and management of NTPCLTd. and NHPC Ltd. for assigning rock mechanicsinvestigations pertaining to various Hydel Projects ofthe country and also for their continuous involvementthrough various executive development programmeson drilling, blasting and tunnelling. Support of ISM inproviding needful support and facilities is also thankfullyacknowledged. Special thanks to Mr. Jerrin Jose,PG scholar for helping to prepare the paper and ShriB.Munshi, STA to support the laboratory studies. Theviews expressed are of the authors and not necessarilyof the organizations they represent.REFERENCES1. Adhikari, G.R,, R.KSinha,Sandeep Nelliat,sagayaBenady& G.H Kotnise (2008-2009) NIRM report,pp1-32. Blindheim, O.T., E.Grv, B.Nilsen (2002): The effectof mixed face conditions (MFC) on hard rock TBMperformance, AITES-ITA World Tunnel Congress,Sydney, March 2002 , pp 1-7.3. Bruland, A., (1998). Hard rock tunnel boring. Ph.D.Thesis, Norwegian University of Science andTechnology, Trondheim.4. Dubey, K.B. (2008), World Tunnel Congress & 34 thGeneral Assembly, September, Agra5. Murthy, V.M.S.R. et al.(2004), A study into themechanical properties of rock for the selectionof tunnel boring machine in Tapovan-Vishnugadhydro power project, Joshimath, Project No.:PCE/CONS/1735/2004, Indian School of MinesDhanbad.6. Murthy, V.M.S.R, Anoop Shukla and NikeshSrivastava(2011), Tunnelling using hard rock tunnelboring machines- Some design and performanceaspects, Intl. Conference on Underground SpaceTechnology, 17-19 January, Bangalore, India, ppLI-04-1 to 10.7. Palmström, A.(1995), RMi –a rock masscharacterization system for rock engineeringpurposes. Ph.D. Thesis, University of Oslo, p. 400.8. Palmstrom & Stille (2010), Rock engineering, pp43-549. Sengupta, S.K, P.K. Saxena & S.S. Bakshi. (2008),Tunnel boring in India- Experience, prospectsand challenges. World Tunnel Congress 2008 –Underground Facilities for Better Environment andSafety-India, pp 1544-155110. Vishnoi R.,(2012),Challenges in Contracting andProcurement of Large Hydro Projects, Washington,Seminar on Risk Management from an Owner’sPerspective.Volume 2 No. 1 January 2013

ISRM (India) JournalInfluence of anisotropic stress conditions ondesign of development workings in bord andpillar miningAbstractR.K. Sinha, M. Jawed and S. SenguptaNational Institute of Rock Mechanics, IndiaThe knowledge of in-situ stress plays a vital role in design of any underground structure in rock. Inmining context, the knowledge of in-situ stress becomes necessary at many stages of mine planning,viz. while deciding about the appropriate layout, designing the ground support and establishing aproper and efficient extraction sequence etc. In today’s numerical analysis based problem solvingapproach, the state of subsurface stress or in-situ stress forms the basic input parameter for analysisof any rock mechanic problem. This paper discusses the directional role of high horizontal stressin Tandsi mine, of Western Coal Fields (WCL). An approach based on wedge analysis and stressanalysis of the layout for bord and pillar mining is discussed in this paper. This helps in understandingthe design requirements for proper layout plan.1. IntroductionThe distribution and magnitude of in-situ stresses affectthe geometry, shape, dimensions, excavation sequenceand orientation of underground excavations (Anireddyand Ghose 1994). The main goals when designingunderground openings in rock / coal (where stressesare likely to be a problem) are to minimize stressconcentrations, create a compressive stress field asevenly as possible (the harmonic hole concept) in theexcavation walls and avoid tensile regions (Hoek andBrown1980). This can be done by changing the shapeand geometry of the openings as well as their orientationwith respect to the known principal in-situ stress. Theknowledge of in-situ stress direction plays a pivotal rolein deciding the orientation and pillaring plan in coal mines(Doliner 2001, Doliner et al. 2001, Bigby et. al. 1992).Once the optimal orientation of the panel is decided, thesize of the slices in bord & pillar mining can be optimizedin order to prevent possible loss of coal in the goaf. Stratacontrol problem associated with Tandsi mine, WesternCoal Fields, India is discussed in this paper.2. Salient features of the mineTandsi Mine lies in the in Chindwara district of MadhyaPradesh. Damua the nearest town is connected withDungaria (headquarter of Kanhan area, WCL) and Parasia(headquarter of Pench area, WCL) by a metaled road(Figure 1). The detailed exploration in Tandsi block hasproved the existence of three coal seams designated fromtop to bottom as seam – III, II and I. Seam III is persistentin nature as well as attained workable thickness in theentire mine area. This is the main potential seam. SeamII has not attained workable thickness of 1.2m and aboveanywhere in the explored area, while seam I has attainedworkable thickness of 1.2 m and above in some part ofthe area explored. The present mining is concentrated at3.5 m thick seam III which is at a depth of 230 m belowthe ground level. The strike of the coal seam in major partof the area is generally EW with localized swings and anaverage gradient of 1 in 15. The immediate roof (3.5 mthick) of seam III is made of fine to medium grained greywhite, moderately hard sandstone with occasional bandsof shale and carbonaceous shale streaks at places. Thefloor consists of sandstone frequently inter bedded withshale and carbonaceous shale. There are no overlyingor underlying workable seams in the mine.Fig. 1 : Location Map of the Tandsi Mine,Madhya Pradesh, IndiaVolume 2 No. 1 January 201316

Influence of Anisotropic Stress Conditions on Design of Development Workings in Bord and Pillar Mining17The access to the mine is through four inclines drivenup to the coal seam. The development of the mine wascarried out by driving mutually perpendicular headingsat a spacing of 45m center to center, thereby creatingan array of pillars of size 45 m x 45 m center to center(Figure 2). The set of headings (almost EW direction)driven along the strike of the coal seam are called levelgalleries and the other set of headings perpendicularto the level galleries are the dip-rise galleries or simplydip galleries. The headings had a rectangular crosssection of 3.6 m width and 3.0 m height. The excavationwas carried out using drilling and blasting using Class Vpermitted explosives and delay detonators to minimizeblast damage to excavations.suspected in case of Tandsi mine. The other probablefactors causing roof failure can be:(i)(ii)(iii)The effectiveness of the roof bolting system.Both the level and dip galleries were supportedsystematically and no delay in supporting thefaces were reported. The anchorage tests of thebolts indicated load bearing capacity of 10 T.Method of blasting. No blast damage was reportedin the mine, as Class V permitted explosive anddelay detonators were used for blasting. Overbreaks were also not reported.Structural instability due to wedge formation inroof of the galleries. A detailed analysis of thewedge formation and its stability is discussedin section 4.0 of this paper; this also negatesthe cause of roof failure due to structuralinstability.Fig. 2 : Key plan showing the roof fall problems encounteredat Tandsi mine3. Mining problem under investigationIn order to achieve trouble free mining operation andsufficient ventilation to the working faces it is desirablethat all the galleries be stable enough to provide accessto the man and material as well as the passage of freshair to the working faces. During development, rooffalls were encountered in dip galleries close to 12th,14th and 16th levels (Figure 2), ellipse portion showslocation of the roof falls). In some instances the rooffalls were extended up to the Rider Seam. Thoughthere was no change in the geometry of the miningand the physical properties of the rock and coal, thepattern of roof fall were not continuous and restrictedin to certain areas. The roof conditions deterioratedupon development even after immediate supporting,due to shear breaks in the roof abutments (Figure 3).The same set of level galleries/dip-rises having similarrock type, strike of the bed and joint pattern did not havecontinuous roof problems. The role of re-orientation ofthe in-situ stress due to influence of discontinuities wasFig. 3 : Nature of roof instability in 14 th Level at Tandsi Mine.The factors such as the effectiveness of roof boltingsystem, method of blasting and structural instabilitynegated the cause of roof failures. Detailed numericalanalysis of the stress induced failure (Sengupta et al.2011) proved the dominant role of the influence of thedirection of the in-situ stress and possible influence ofthe stress perturbation due to faults. The present paperinvestigates in detail the role of structural instability due toformation of wedges in the roof and the directional role ofin-situ stress through numerical modeling for orientationof safer and trouble free galleries.Prior to the stress measurement at Tandsi Mine, themanagement of the mines had made many trial and errorcombinations by reducing the width of the galleries to 3.6m from an initial width of 4.5 m. The details of differentcombinations for support system resorted by the minemanagement is given in Table 1, however none of themethods were found effective.Volume 2 No. 1 January 2013

18ISRM (India) JournalTable 1 : Summary of the different system of support, tried by the mine management,for development galleries at Tandsi mineParameter Option 1 Option 2 Option 3 Option 4Roof span (m) 4.5 3.6 3.6 3.6System of support roof bolt roof bolt roof stitching roof bolt with W-strapLength of bolt (m) 1.5 1.5 1.8 and 1.5 m longeye boltsNo of bolts in a row 3 3 2 4Spacing between rows 1 1 1 0.9Distance from pillar sideand angle of the boltPerformance of Support0.75 0.3 0.3 0.3Massive roof falls atnumber of placesRoof falls at numberof placesRoof falls in level anddip galleries1.8Frequent roof fallsreducedParameter Option 5 Option 6 Option 7Roof span (m) 3.6 3.6 3.6Table 1 : (Contd.)System of support roof bolt with W-strap resin bolting with w strap resin bolting staggered patternLength of bolt (m) 1.8 2.1 2.1No of bolts in a row 4 5 4/5Spacing between rows 0.5 0.6 0.6Distance from pillar sideand angle of the bolt0.3 0.3 0.2Performance of support Roof falls at number of places Roof falls at number of places Roof falls at number of placesNote: Pillars have no sign of loading however cracks were observed in the roof of the gallery, in all the options at someplaces4. Wedge analysis of the discontinuitiesencountered at Tandsi mineRMR report of the Tandsi mine, prepared by WCL Nagpur,provided by the mine management, reveals two sets ofpredominant vertical joints observed in the sandstone.One of the joint sets trending N-S and the other N150 0 .The joint along the seam is another obvious joint set,which has been considered for the wedge analysis.The wedge analysis of Tandsi mine was carried outusing the Software ‘Unwedge’ Supplied by RocscienceInc. Canada. The software Unwedge carries out a seriesof calculations based on the input provided by the userin terms of the geometry of the opening, the joint setinformation, the joint property and the support information.The calculation steps include:1. Determination of wedge geometry using blocktheory (Goodman and Shi, 1985)2. Determination of the individual forces acting on awedge and then calculation of the resultant activeand passive force vectors for the wedge.3. Determination of the sliding direction of thewedge.4. Determination of the normal forces on eachwedge plane.5. Computation of the joint shear strength, andtensile strength (if applicable)6. Calculation of factor of safety against sliding ofthe block.Wedges are formed by the intersection of 3 – joint planesand excavation. The wedges so formed are tetrahedralin shape (in general the three joint planes forms thethree sides of the tetrahedron and the fourth side isformed by the excavation boundary). In an Unwedgeanalysis there are fair chances of formation of prismaticwedges, this occurs if two of the joint planes strike in thesame direction resulting in a prismatic shape rather thanthe tetrahedral shape of the wedge. The geometricalproperties of each wedge are described by its volume,wedge face area and the normal vectors for eachwedge plane.The forces acting on the wedge are categorized into twotypes, viz. the active and passive forces. These forcesare utilized in the calculation of the factor of safety of thewedges. All driving forces are treated as active forcesVolume 2 No. 1 January 2013

Influence of Anisotropic Stress Conditions on Design of Development Workings in Bord and Pillar Mining19and all resistive forces are treated as passive forces. Theactive force vector is given by equation (1):...(1)Where, = resultant active force, = vectorrepresenting wedge weight, = vector representingthe weight of shotcrete on the wedge, = activepressure (Support) force vector , water force vector and= seismic force vector. The passive force vector isgiven by equation (2):...(2)Where, = resultant passive force vector, =shotcrete shear resistance force vector, = passivesupport pressure force vector and = resultant boltforce vector.Once the active forces are computed, this is utilized fordetermination of the direction of the sliding of wedge. Itis worth noting that the passive forces do not influencethe sliding direction. For any tetrahedron, there can be 7– possible directions of sliding .The vector represents the mode of falling or lifting of thewedge. The and vectors represent the modeof sliding on a single plane. The and vectorsrepresent the mode of sliding of the wedge along theline of intersection of two joint planes. The equations forthe sliding direction vectors are given by equations (3),(4) and (5)....(3)...(4)...(5)Where, = falling or lifting direction of wedge, â = unitdirection of active force, = resultant active force, =sliding direction on joint ‘i’, n i= normal to joint face ‘i’directed into wedge, n j= normal to joint face ‘j’ directedinto wedge and = sliding direction on joint ‘I’ and ‘j’(intersection of joints).After the evaluation of the sliding direction, the evaluationof normal force on each of the three joint planes ofthe tetrahedron is affected. The equations (6), (7) and(8) describe the normal forces on the planes of thetetrahedron.For falling or lifting wedge N i= 0, N j= 0, N k= 0 ...(6)For sliding on a single joint ‘i’ N i= –F A, n i, N j= 0, N k= 0 ...(7)For sliding along joint ‘i’ and ‘j’...(8)Now, for the computation of the resisting force on thewedge, the normal force acting on each joint plane isevaluated. The normal stress is computed based on theactive and passive normal force computed on the jointplane and is given by equation (9)....(9)Where, σ niis the i th joint plane, N iis the normal force onthe i th joint and a iis the area of the i th joint. The resistingstress due to the shear strength of the joint is representedby the Mohr-coulomb failure criteria given by...(10)Eventually the resisting force due to shear strength ofthe joint is given by...(11)Where, = the magnitude of the resisting force due toshear strength of the joint = the shear strength ofthe joint the area of the joint the cohesionof the joint plane the angle of internal friction of thejoint strength and the angle between the sliding directionand the joint.The resisting force due to the tensile strength of the jointis taken as zero for the analysis in this paper.Finally the factor of safety for the three cases viz., (i)the falling factor of safety - (ii) unsupported factor ofsafety - and (iii) the supported factor of safety - iscalculated. The maximum amongst the three is reportedas the factor of safety of the wedge.As per the development carried out at Tandsi mine,four directions of galleries (Table 2) will be sufficient torepresent the drivage of the mine. Table 3 lists the detailsof the joint sets present in the roof.Table 2 : Direction of galleries at Tandsi mine.Sl. No. Location Gallery Trend Plunge1Level 078 0026D /9L2 Dip /Rise 171 043Level 120 01.710D / 14L4 Dip / Rise 033 03.7Volume 2 No. 1 January 2013

Influence of Anisotropic Stress Conditions on Design of Development Workings in Bord and Pillar Mining21Fig. 5 : View of the wedges formed, with gallery orientation 120/01.7, Output from Unwedge software.As observed from the stereographic plot of the jointsvis-a vis the gallery directions as shown in Fig. 4 andsummary of the results of Unwedge analysis in Table 4,the following observations are made:1. For the gallery 078/00, wedge is formed in the roofand tends to drive the wedge along Joint set 1. Thewedge weight increases as the width of the galleryis increases. The factor of safety for 4.5 m gallery is0.558 without any support or shotcrete. The wedgeweight being 0.139 ton and extends barely highenough into the roof, this means a minimal supportof less than 1 ton capacity can support the roofeffectively.2. For the gallery 171/04, wedge is formed in the roofand tends to drive the wedge along Joint set 2. Thewedge weight increases as the width of the galleryis increases. The factor of safety for 4.5 m gallery is0.901 without any support or shotcrete. The wedgeweight being 0.962 ton and extends barely highenough into the roof, this means a minimal supportof less than 1.5 ton capacity can support the roofeffectively.3. For the gallery 120/01.7, wedge is formed in the roofand tends to drive the wedge along Joint set 2. Thewedge weight increases as the width of the galleryis increases. The factor of safety for 4.5 m gallery is0.456 without any support or shotcrete. The wedgeweight being 14.98 ton and extends barely highenough into the roof, this means a minimal supportof three bolts of length 0.5 m with capacity 6 ton eachcan support the roof effectively to a factor of safety2.0.From the results of the Table 4 and the observations ofthe Unwedge analysis, it is quite evident that the rooffalls as reported in Tandsi Mine is not because of anystructural instability (Wedge failure), rather it indicatestowards the role of high horizontal stresses that may becreating trouble in the roof strata.5. Investigation of Stress Redistribution due toMining GeometryInvestigation conducted in Australian coal mines (Galeand Fabjanczyk, 1991) has established a relation betweenroof failure in the roadways and the angle betweenthe roadway axis and the maximum horizontal stressdirection. Actual measurement of stress in vicinity ofthe fault zone proved the rotation of the stress directionalong one of the galleries (Sengupta et.al 2011), whilethe regional stress direction away from the fault zonewas at 45 degrees to galleries. In a typical bord andpillar mining method the dip drives and level galleries areVolume 2 No. 1 January 2013

22ISRM (India) Journaldriven perpendicular to each other. Now in a particularset of direction of maximum horizontal stress one of thesemay be oriented unfavorably with the orientation of themaximum horizontal stress. A detailed investigation iscarried out by numerical modeling to establish the mostfavorable direction of the dip drives/level galleries vis avis direction of maximum principal horizontal stress fromthe stability point of view. For the study of redistribution ofstresses due to change in mining geometry three caseswere considered.Case 1: Orientation of Max. Horizontal Principal Stress(σ H) is perpendicular to orientation of level gallery.Case 2: Orientation of Max. Horizontal Principal Stress(σ H) is parallel to orientation of level gallery.Case 3: Orientation of Max. Horizontal Principal Stress(σ H) is 45 o to orientation of level gallery.The objective of the study is to estimate effect of theabove three conditions on the stability of roof so thatproper measure can be taken to reduce the roof stabilityproblem by change in geometry of the workings and alsoto estimate the support requirement.5.1 Model Setup for Evaluating Re-orientation ofDevelopment WorkingTo investigate the effect of in-situ stress direction onworking of a developed bord and pillar panel, a panel of3 x 3 pillars was made in EXAMINE3D program. Pillar sizeof 45m center to center and the gallery size of 4.5 m x 3 mwere selected. Development excavations were made byuse of polylines and node lines. Between the two nodelines the skin of the excavation was extruded. The skin ofexcavation was discretized using the default discretizationscheme of the program with a mesh density factor of unity.The crossing of excavation was made by deleting therequired elements from the crossing points; a node linewas drawn along the deleted portion of the excavation,this node line was extruded up to the next crossing pointto form a leakage proof excavation Fig. 6.Fig. 6 : Discretized model for a 3 x 3 pillar developmentpanel in Examine 3D5.2 Initialization of In-Situ stress in Examine 3DExamine 3D has an option of using the gravity as wellas the in – situ stress data. The in – situ stress valuescan be fed in the form of principal stresses with theirrespective dip and dip direction. The measured valueof the regional stress for Tandsi mine (Sengupta et al.2004) was utilized, which is tabulated in the form of inputrequired by Examine3D.Table 5 : In-situ stress values of Tandsi Mine, used inExamine 3D, when the major principal stressis along level galleriesMagnitude(MPa)Direction(degrees)MajorPrincipalStress (σ H)IntermediatePrincipalStress (σ V)MinorPrincipalStress (σ h)9 4.5 590 0 0Dip (degrees) 0 0 90To evaluate the second option when the major principalstress is perpendicular to the level gallery, the stressdirections of σ Hand σ has given in Table 5 above isinterchanged.For evaluating the third option of the case when the majorprincipal stress is at an angle of 45° from the level galleryand still horizontal. The Stress directions were changedin the input as given in Table 6.Table 6: In-situ stress values of Tandsi Mine, used inExamine 3D, when the major principal stressis at an angle of from the level galleries.Magnitude(MPa)Direction(degrees)Dip(degrees)MajorPrincipalStress (σ H)IntermediatePrincipalStress (σ V)MinorPrincipalStress (σ h)9 4.5 5135 45 00 0 90Thus overall the stress orientation in the three cases isas follows:Case 1 : the major principal stress acts along east –west direction. The galleries are driven north – southand east – west.Case 2 : the major principal stress acts along north –south direction. The galleries are driven north – southand east – west.Case 3 : the major principal stress acts along Northeast –Southwest direction. The galleries are driven north – southand east – west.Volume 2 No. 1 January 2013

Influence of Anisotropic Stress Conditions on Design of Development Workings in Bord and Pillar Mining235.3 Rock Mass Property and Failure Criteria forEvaluating the Factor of SafetyThe rock mass elastic modulus was taken as 5.0 GPaand Poisson’s ratio of 0.25 was utilized in the model. ForIndian coal measure rocks, the Sheorey’s Failure criterionhas been found suitable by researchers in India (MuraliMohan 2001). This criterion uses the 1976 version ofRMR of Bieniawski for reducing the laboratory strengthparameters to give the corresponding rock mass values.The basic CMRI –ISM RMR is directly used here insteadof Bieniawski’s RMR, since this procedure has beenfound to be acceptable after application in 18 - coal minecases (Kushwaha et.al 2010). Sheorey’s criterion for rockmasses is defined as:is nonlinear (Figure 7) in the form, where, whereas the Mohr Coulomb criterion islinear. The value of τ smobtained from Sheorey’s criterionwas increased by 10% and that of ϕ Omwas reducedby 5° for use as Mohr Coulomb criterion. Consideringlarge number of Indian case studies, Murali Mohan et al(2001) prescribed that the values determined by abovementioned method can be safely taken for modelling....(12)The subscript m refers to rock - mass, where σ 1is thetriaxial strength of rock mass (MPa), σ 3is the minorprincipal stress or the confining stress (MPa), b mis theexponent of the failure criterion that controls the curvatureof the non-linear Sheorey’s failure criterion σ cmand σ tmand σ tmis the compressive strength and tensile strengthof the rock mass respectively, which is defined as :...(13)...(14)...(15)The symbols without the subscript m are the laboratorydetermined values for intact rock.As the program Examine 3D has no facility for usingdifferent failure criteria other than the Mohr coulomb andthe Hoek and Brown failure criterion; the Mohr CoulombEquivalent (best fit) of Sheorey’s failure criterion wasused. The rock mass shear strength (or cohesion) τ sm,the coefficient m Omand the angle of internal friction ϕ Omare obtained from Sheorey’s criterion asFig. 7 : Schematic of using equivalent Mohr CoulombCriterion of the Sheorey’s Criterion.Using the compressive strength of intact coal specimenas 42 MPa, tensile strength of 5 MPa and RMR of 56, theMohr Coulomb equivalent cohesion is calculated as 1.33MPa and angle of internal friction as 29.38 degrees.5.4 Model Result of Re-orientation of DevelopmentWorkingPlot of the factor of safety contours on the skin of theexcavations during development shows major roofproblems, when one of the stresses is parallel to either ofthe galleries (see the stress block in Figure 8); the area ofthe roof is completely filled with the FOS contours falling inthe range of 0 to 0.7 (Figure 8) indicating directional failure.This situation is applicable to both the Case1 and Case 2....(16)...(17)It is, however, found that the values of rock mass cohesionτ smand friction angle ϕ Omhas to be changed slightly toaccount for the fact that the Sheorey’s Failure criterionFig. 8 : Plot of factor of safety contours on the skin of excavationsduring development, for the case, when one of the majorhorizontal stress is parallel to the east – west gallery.Volume 2 No. 1 January 2013

24ISRM (India) JournalFig. 9 : Plot of factor of safety (FOS) contours on the skin ofexcavations during development, for the case, when one ofthe major horizontal stress is at to one of the gallery. Showsreduced roof problems in both galleries.But in the Case 3, when the major principal stress isoriented at to the working, the roof problem diminishesrapidly as seen in Fig. 9.6. ConclusionThe wedge analysis of the Tandsi mine reveals that theexisting joint sets have minimal effect on the instabilityof the roof. In fact the wedges extend into the roof up to0.38 m and minimal roof bolting can provide sufficientstability of the roof. However, in actual the roof is foundto be quite unstable even for rock bolts of length upto1.8 m in length. There is no report of blasting damage orthe delay in support installation. This calls for attentionon other factor i.e. the stress related instability of thegalleries at Tandsi mine. Detailed numerical modeling ofthe Tandsi mine reveals the following:(a)(b)Plot of factor of safety contours on the skinof excavations during development, for thecase when one of the major horizontal stresscomponents is parallel to the level gallery, thedip – rise gallery experience major roof problems(Figure 8).Plot of factor of safety, contours on the skin ofexcavations during development, for the case,when one of the major horizontal stress is at 45 0to the level gallery. Shows reduced roof problemsin both level as well as dip – rise galleries(Fig. 9).Re-orientation of the development workings of the minewith respect to the direction of the in-situ stress canresolve the stress governed failure in the roof of thegalleries.ReferenceS1. Anireddy, H.R. and Ghose, A.K.(1994). Determinationof In-Situ Horizontal Stresses by Hydraulic Fracturing inUnderground Coal Mines, Journal of Mines Metals andFuel, July 1994, pp 145-155.2. Barton, N.R. (1974). A Review of the Shear Strength ofFilled Discontinuities in rock. Norwegian Geotech. Inst.Publ. No. 105. Oslo: Norwegian Geotech. Inst.3. Bigby, D.N.; Cassie, J.W. and Ledger, A.R.(1992). AbsoluteStress and Stress Change Measurements in British CoalMeasures, Proceedings of ISRM Conference on RockCharacterization, Eurock’92, pp 390-395.4. Dolinar, D.R. (2001). Variation of Horizontal Stresses andStrains in Mines in Bedded Deposits in the Eastern AndMid-Western United States, 22nd International Conferenceon Ground Control in Mining, pp 178-185.5. Dolinar, D.R.; Mucho, T.P. and Oyer; D. C; (2001). Advanceand Relieve” Mining, a Method to Mitigate the Affects ofHigh Horizontal Stresses in the Mine Roof, SME AnnualMeeting, Feb26-28, Denver, Colorado, Preprint 01-113.6. Goodman, R.E. and Shi, Gen-hua. (1985). Block Theoryand its application. Prentice Hall Inc., Englewood Cliffs,New Jersey. ISBN 0 – 13 – 078189 – 7.7. Gale, W.J. and Fabjanczyk, M.W. (1991).Strata controlutilizing rock reinforcement techniques in Australian coalmines, Symposium on roof bolting, Poland, pp.362–373.8. Hoek, E. and Brown, E.T. (1980). Underground ExcavationsIn Rock, Institution of Mining and Metallurgy, 1980, pp100,183-241.9. Kushwaha, A.; Singh, S.K.; Tewari, S.; Sinha A. (2010).Empirical Approach for Designing of Support System inMechanized Coal Pillar Mining. International Journal ofRock Mechanics and Mining Sciences , 47 (7). pp. 1063-1068.10. Murali, Mohan G.; Sheorey, P. R. and Kushwaha, A.(2001) Numerical Estimation of Pillar Strength in CoalMines. International Journal of Rock Mechanics and MiningSciences , 38 (2). pp. 1185-1192. ISSN 1365-160911. Report on RMR Tandsi Mine, WCL Nagpur.12. Sengupta, S., Sinha, R.K., Subrahmanyam, D.S. andJoseph, D. (2011) ‘Investigation in to the Causes of SevereRoof Problems in some Indian Coal Mines and formulationof Guidelines to Reduce Ground Control Problems’,Int. J. Mining and Mineral Engineering, Vol. 3, No. 4,pp.290–302.13. Sengupta, S.; Chakrabarti, S.; Gupta, R.N.; Subrahmanyam,D.S.; Joseph, D.; Sinha, R.K.; Kar, A.; Sanyal, K.; Prasad,B.; and Wanarey, R.M. (2004). Measurement of insituStress by Hydrofrac Method and Investigations onRedistribution of in-situ stress due to local Tectonics andmethods of working at Tandsi and Thesgora mines, WCLto devise a suitable support plan SSR. A Coal S&T Project,funded by Coal S&T grant of Ministry of Coal, Govt. of India,Project no. MT – 117.14. Sheorey, P.R.(1997). Empirical Rock failure criteria, A.A.Balkema, Rotterdam.15. Venkateswarlu, V.; Ghose, A.K.; Raju, N.M. (1989). RockmassClassification for Design of roof Supports-A StatisticalEvaluation of Parameters, Mining Science and Technology,Volume 8, Issue 2, March 1989, Pages 97-107, ISSN 0167-9031, DOI: 10.1016/S0167-9031(89)90507-0.Volume 2 No. 1 January 2013

STRATA MONITORING STUDIES IN BLASTING GALLERYPANEL DURING DEPILLARING BASED ON FIELDINSTRUMENTATIONS. Kumar ReddyNational Institute of Rock MechanicsV.R. SastryNational Institute of Technology Karnataka, IndiaA challenging task for mining professionals is to extract natural resources like coal from undergroundwith utmost safety. The challenge becomes more when the thickness of coal seam is high. BlastingGallery (BG) method of depillaring thick coal seam is one of the productive method with favourableeconomics, high production and productivity. In this method, stability of workings and easily cavabilityof goaf is very important for safely extraction of pillars, safety of men and machinery. In this paper,strata monitoring data of a blasting gallery panel is analyzed for the stability of pillars and workingsin a Blasting Gallery panel during depillaring in specific geo-mining and working conditions of aunderground mine in Southern part of India.Keywords: Underground coal mining, Thick seam mining, Blasting Gallery method, Strata monitoringstudies.1. IntroductionIn India, the gross reserves of coal are presently estimatedat around 293.49 Billion tonnes (Bt) up to the maximumdepth of 1200 m with proven reserves of 118.14 Bt,sufficient to last the next century at an annual rate ofproduction of over 1180 Mt at present level of extraction(Anon, 2012). The demand of coal in the country isincreasing year by year as energy sources from differentindustries. With the increasing demand of coal, moremechanized opencast mines are coming up. However,at present only 38% of Indian coal reserves is mineableby opencast mining within economic limit whereasthe remaining 62% is to be exploited by undergroundmining (Singh et al., 2004). The share of undergroundcoal production in the country has declined from 73% in1974-75 to 10% in 2011-2012. For a healthy and balancedgrowth of coal mining industry in the coming decade, itis essential that underground production should increaseat a more rapid rate. This is possible only by introducingextensive mechanization in underground mines andadopting new technologies.About 50% of coal reserves in India are in seams thickerthan 4.5m, which come under the category of thick seams,the exploitation of which is consistently posing challengesto the mining engineers. Extraction of thick seams byconventional hand section method is neither productivenor effective from the conservation point of view. Thepercentage of extraction by hand section mining in thickseams is as low as 25-30%. Lot of good grade coal hasbeen lost and million tonnes of coal are standing onpillars. Sand stowing for working of thick seams cannot beconsidered as an option because the cost is prohibitive.Sand has become an increasingly scarce commodityalong with timber. At the same time, the coal industrywas in search of an economic method to achieve higherpercentage of extraction (70 – 85%) and needs a suitabletechnology to overcome the problems in the extraction ofthick seams by conventional bord and pillar method.Charbonnage de France (CdF) suggested BlastingGallery (BG) method for extraction of virgin thick seamsas well as developed pillars in thick seams. The first BGpanel was started in the country at East Katras Collieryin Jharia Coalfield (BCCL) and Chora-10 Pit Colliery inRaniganj Coalfield (ECL) in the year 1987 in collaborationwith France. Due to strata problems, the method was notsuccessful at East Katras Colliery where overriding ofthe pillars occurred in one panel. Whereas at Chora-10Pit Colliery, the method was partially successful givingencouraging results. However, the expected productionand percentage of extraction could not be achieved inboth the mines (Pandey et al., 1992). The SingareniCollieries Company Ltd. (SCCL) adopted this method inthe year 1989 at GDK No. 10 Incline for extraction of coalin virgin area. The method was very successful resultingin 85% of extraction with high productivity (SCCL internalreport, 2005). Realizing the rate of success, BG methodof extraction is gearing up its future potentiality.25Volume 2 No. 1 January 2013

26 ISRM (India) JournalThe soft nature of coal mass and presence of easilycaveable overlying roof strata play a crucial role for thesingle working of a thick coal seam. However, both,the coal mass and the roof strata of Indian coalfieldsare, relatively, strong and massive. Here location ofa prominent parting plane within the roof strata playsan important role in estimating the void between thecaved wastes and overhanging roof inside the goaf.For these strata conditions, the value of limiting spanof the overhang, generally, remains high, whose fallmanifests dynamic loading over pillars facing goaf line.Due to increased height of the void to be filled, theproblems associated with the dynamic loading needspecial attention for success of single lift working of athick coal seam. So, BG panels need to be monitoredwith instruments for complete extraction of panels withsafety without any strata problem by taking protectiveand precautionary measures beforehand. This paperdiscusses strata monitoring experiences of BG panelduring depillaring in a given geo-mining and workingconditions.2. BLASTING GALLERY METHOD (BG)In brief the method involves splitting along level ofdeveloped pillars in the bottom section, into two or threerectangular stooks (Fig. 1) and adequately supportingwidened galleries by hydraulic props and roof bars atleast two pillars ahead of the pillar under extraction. Thestooks are extracted by drilling a ring of long holes uptothe full seam thickness by Jumbo drills and blasting. Theblasted coal from the goaf is loaded through the levelgalleries/splits by remote controlled load-haul-dumpers(LHD). LHDs discharge the coal into the armoured chainconveyors set within 100m from the extraction line foronward transport to a small bunker.2.1 Preparatory WorkThe galleries in the panel are widened to 4.8 m andheightened to 3 m for efficient manoeuvrability of LHDsand drill jumbos, and galleries upto two pillars of theline of extraction are supported by 40 tonne open circuithydraulic props. The props are set at an interval of 0.7m such that a clear space of 4.2 m was available for afree movement of the machines. The method of supportof galleries and junctions in the panel is shown in Fig. 2.One chain conveyor in level is installed for coal transportto a bunker.Fig. 2 : Junction and gallery support in bottom section at theworking face (Gupta et al., 1990).2.2 Method of ExtractionInitially, the pillars are divided by driving 4.8 m x 3 m levelsplit galleries. The splitting of pillars is restricted to twopillars ahead of the line of extraction. A diagonal line offace is maintained at about 60 0 .While retreating, the galleries are widened on both thesides by drilling long holes in a ring pattern upto the fullthickness of the seam and blasting. Holes (42 mm) aredrilled at an angle of 30 0 towards the goaf. The rings ofholes are spaced at 1.4 m. Only one ring is drilled andblasted at a time. Drilling is done with the roof supportbut the supports are withdrawn just before the blasting.The pattern of drilling is shown in Fig. 3.Fig. 1 :Typical layout of Blasting Gallery method inunderground coal mine.Fig. 3 : Ring hole blasting pattern and charge distributionA special low strength explosive is used in long holeshaving the requirement of upto 2 kg per hole. A specialnon-incendive detonating cord is used in long holes.Hallow PVC tube spacers, 50 cm long, are used toseparate the charge in the shot holes. A hollow PVCsleeve containing an explosive cartridge was inserted atVolume 2 No. 1 January 2013

Strata Monitoring Studies in Blasting Gallery Panel During Depillaring Based on Field Instrumentation27one metre inside the hole from the mouth which containedthe end of the detonating fuse attached with an electricdetonator as shown in Fig. 4. About 1 m long clay plug wasprovided upto the mouth of the hole in the conventionalway. After charging, blasting is carried out. The blastedcoal in the goaf was loaded by electro-hydraulic remotecontrolled LHDs. The remote control was pneumaticallyoperated. The LHD travelled from goaf edge to the loadingpoint and discharged on to armoured chain conveyor.40 m and between No.3 Seam and No.4 Seam is 4.5 mto 5.5 m. Blasting gallery technology is introduced andpractised in 3 Seam. The seam no. 3 is dipping at about1 in 5.2 lies at 321 to 348 m depth. The 10.97 m thick 3seam is being worked in the bottom section to a heightof about 3 m along the floor, leaving 1.5 m thick coal inthe bottom, and area of the panel is 17369 m 2 consistsof 6 pillars with 50 x 60 m size. It is overlain by a mediumgrained white sandstone by 23.16 m thick forms the mainroof. The underlying No. 4 seam was unmined. The panelworkings were observed free of water. Other overlyingseams were found to be non-commercial (Fig. 5). The BGpanel-3B, is selected for the present investigations.Fig. 4 : Charging details in ring holes (SCCL internal report, 2005).2.3 Advantages with BG MethodThe advantages of BG method include;1. Extraction of 5-12 m thick seams in a single slice bycaving.2. Extraction of small size panels not suitable for longwallmethod.3. Extraction of hard coals not suitable for ploughs andshearers.4. Higher production and productivity.5. Less capital intensive compared to longwall.6. Less skilled man power is needed as compared tolongwall.7. In case of BG failure, the equipment can be used forheading drivages.8. The workers/operators are always under thesupported roof.3. Field investigationsThe investigations were carried out in an undergroundcoal mine with coal formations of Kamthi and Barakarseries located in Southern India. Three seams areoccurring in the mine viz., 3A Seam, 3 Seam and 4 Seam.The parting between No. 3A Seam and No.3 Seam isFig. 5 : Borehole section No.441,GDK-10 Incline, SCCL.An already-extracted panel was lying towards northernand western side of Panel-3B, whereas towards the southside and eastern, there was a virgin panel (Fig. 6). Theimmediate overlying strata were observed to be strong andmassive with a caveability index of more than 2915 (NIRM,1999). The presence of a difficult roof over the nearly 11m high void in the goaf created difficult conditions for pillarmining the total thickness of the seam in a single lift. Theincrease in goaf height due to roof coal extraction by BGmethod was observed to be of considerable importancefor stability of the pillars. There was a remarkable changein the width/height ratio of the pillars which faced the goafof the adjacent mined pillars (Rajendra Singh, 2004).Fig. 6 : Plan of Pane-3BVolume 2 No. 1 January 2013

28 ISRM (India) JournalInitially, 50 m x 60 m pillars were divided into three halvesby driving 4.8 m x 3 m level split galleries. The size ofstooks after splitting was 15.2 m x 50 m. The splittingof pillars was restricted to 2 pillars ahead of the line ofextraction. A diagonal line of face was maintained atabout 60 0 .3.1 Safety Factor of the PillarsUnder normal pillar extraction condition, the localmine stiffness remains more or less constant while thereduction in pillar strength with the reduction in pillar sizegenerates a situation conducive to violent failure. Here,increasing the extraction ratio by splitting/stoking of pillarsahead of the face may be dangerous to the working area.Laboratory scale specimens become elasto-plastic whenwidth/height ratios approach 8 (Das 1986). In accordancewith the field data available for the actual failure of apillars (Sheorey 1993), the post failure modulus of a pillarwith width/height ratio about 4 becomes positive and itsbehaviour changes from strain-softening to elasto-plastic.Fortunately, the BG does not involve the process ofsplitting/stoking ahead of the face, except for splitting andslicing the pillars being extracted. Under these conditions,the chance of the violent failure of a pillar becomes lowand is limited to the pillar being extracted. The safetyfactor of the pillars of panel-3B remains nearly 2.33 fornormal height (3 m) pillar extraction, while the same forfull-height working of the seam by the BG method (11 m)with double splitting goes below one.Table 1: Pillar size variation as per regulation 99 ofIndian Coal Mining Regulations, 1957 (CMR 1957).3.2 Strata MonitoringField instrumentation was carried out in panel-3B tostudy stress distribution in the panel, load on hydraulicprops in galleries, convergence in galleries, roof layersmovement and stress change in the panel. Details of fieldinstrumentation programme are given here (Fig. 7):• Stress measurements in BG workings. Five vibratingwire stress cells, S 1at 66BLN/39D, S 2at 67LS/39D, S 3at 67ALS/39D, S 4at 68ALS/39D and S 5at 68BLS/39D,were installed in the BG panel.• Load over O.C. props in galleries. Vibrating wire loadcells were installed on the O.C. hydraulic props, till10 m ahead of working face in galleries. Recordingsfrom load cells were obtained at every 10 m interval.Load cells were shifted to new stations after every 10m of face retreat in the galleries.• Convergence in gate roads. Roof to floor convergencewas monitored at every 10 m interval in galleries usingtelescopic convergence indicators.• Immediate roof layers movement. Three Tell-taleextensometers, T1 at 66L, T2 at 67L and T3 at 68L,were installed in the junctions of the BG panel.Depth cover(m)Pillar size (center to center) for differentgallery widths (m)3.0 m 3.6 m 4.2 m 4.8 m360 39.0 42.0 45.0 48.0Pillars formed (Table 1) in accordance with the CoalMining Regulations possess adequate safety factorsand a high w/h ratio which sustain the various miningconditions resulting from pillar extraction at normalheights. However, there is an indirect increase in theheight of pillars due to the winning of the roof coal by theBG method (Singh et al., 2007). The process of roof coalwinning affects the stability of pillars designed for normalheight workings developed in accordance with the CoalMining Regulations.Fig. 7 : Location of different monitoring instruments.4. Results and discussion4.1 Stress Variation Over the PillarsThe measurements obtained from vibrating wire stresscells at 66BLN/39D (S 1), 67LS/39D (S 2), 67ALS/39D(S 3), 68ALS/39D (S 4) and 68BLS/39D (S 5) are presentedVolume 2 No. 1 January 2013

Strata Monitoring Studies in Blasting Gallery Panel During Depillaring Based on Field Instrumentationwith respective to area of extraction of Panel-3B is presented in Fig. 10. There29was anincrease in load of 22 t over O.C. props for the initial area of extraction of about 4000 min Fig. 8 and 9. Variation of stress was found in all cells and observed on O.C. props indicated the occurrence of roof2its magnitude increased as the area of extraction increases and 32 fall t for in further the area goaf, of extraction due to of induced about 5300 blasting m 2 the panel. practices. Afterand the face retreated closer to the station. It can be seen Subsequently, that, increase noticeable in load decrease was in load observed of 25 t over with O.C. respective props was observed to forthat the stress cell (S 1) recorded higher stress compared further area of of extraction about of 6200 27 mt 2 for . Thus, 7000 the sudden m 2 , 28 decrease t for 8000 in load mobserved 2 , onto other stress cells installed in the panel-3B. The reasons O.C. props32 tindicatedfor 8600them 2 occurrenceand 39 tofforroof10060fall inmthe 2 . Thesegoaf, duerecordingsto induced blastingcould be the large overhangs in goaf towards 66AL North, showed regular increase in load, indicating periodic buildupof load on galleries, and increase in load may be duepractices. After that, increase in load was observed with respective to area of extraction of66BL North and 67L North and nearer to the goaf edge27 t fordistance compare to the other stress cells in the panel. to 7000 non-caving m 2 , 28 t for of 8000 goaf. mO.C.2 , 32 t for 8600 m 2 and 39 t for 10060 m 2 . Theserecordings showed regular increase in load, indicating periodic build-up of load on galleries,Further O.C props experienced higher loads in 66AL5and increase North, in load 66BL may be North, due to non-caving 67L and of goaf. 67AL O.C. South, and load66BLN/39Dvaries Further from O.C 30 props t - 39 experienced t. The panel higher loads experienced in 66AL North, supports 66BL North, 67L67LS/39D4and 67AL displacements South, and load in varies galleries from 30 of t 66AL - 39 t. North, The panel 66BL experienced North, supports67ALS/39Ddisplacements 67L and in galleries 67AL of South. 66AL North, 66BL North, 67L and 67AL South.Increase in stress (MPa)Increase in stress (MPa)32103500 5500 7500 9500 115005excavation area (m 2 )66BLN/39D68ALS/39D68BLS/39DFig. 8 : Stress recordings with respective to area ofexxtraction in Panel-3B.4.2 Load Variation in the GalleriesThe load over O.C. props was recorded during panelextraction. Initial load in all the load cells was maintained 5 t.The change in load was calculated based on final load recordedbefore the removal of O.C. prop as face approached it.The change in load of O.C. props with respective to area ofextraction of Panel-3B is presented in Fig. 10. There was anincrease in load of 22 t over O.C. props for the initial areaof extraction of about 4000 m 2 and 32 t for further area ofextraction of about 5300 m 2 in the panel.Subsequently, noticeable decrease in load of 25 t overO.C. props was observed for further area of extractionabout 6200 m 2 . Thus, the sudden decrease in loadMax. change in load (t)4030201000 2000 4000 6000 8000 10000 12000area of extraction (m 2 )Fig.467LS/39DFig.10 :10Loadloadrecordingsrecordings iningalleriesgalleriesininPanel-3B.Panel-3B.67ALS/39D4.3 Convergence in Galleries368ALS/39D4.3 Convergence in galleriesRoof to floor convergence was monitored at 10 m intervals68BLS/39DRoof to (i.e. floor station convergence C1, was C2, monitored C3, C4, at 10 C5, m intervals C6, (i.e. C7, station C8, C1, C9 C2, and C3, C4, C5,2C10) from goaf edge in each level of Panel-3B duringC6, C7, C8, C9 and C10) from goaf edge in each level of Panel-3B during depillaring.depillaring.1The convergence in galleries with respective to area of extraction analysed duringThe convergence in galleries with respective to area ofdepillaring in Panel-3B are shown in Fig. 11. Convergence is increasing with area ofextraction analysed during depillaring in Panel-3B are0extraction increased. Results revealed that all the stations that recorded cumulative100 80 60 40 200shown in Fig. 11. Convergence is increasing with area ofextraction increased. Results revealed that all the stationsGoaf edge distance (m)that recorded cumulative convergence higher than 100mm were experiencing large overhangs in goaf evenFig. 9 : Stress recordings with respective to goaf edgethough induced blasting practices in goaf.distance in Panel-3B.Page 11 of 15Convergence (mm)200160120804000 2000 4000 6000 8000 10000 12000excavated area (m 2 )Fig. 11 : Convergence recordings in galleries withrespective area of extraction in panel – 3B.Volume 2 No. 1 January 2013

30 ISRM (India) Journal4.4 Immediate Roof Layers MovementThe trend of immediate roof layer bed separation changerecorded in the panel-3B. The maximum bed separationrecorded at 68L/39D junction was 3 mm and 0 mm,respectively, in the anchor placed at 7 m and 2m. Thisindicates that there was no deformation of the immediatecoal roof which forms the main roof, whereas, highdeformations were recorded in convergence stations maybe due to massive sandstone layers overhang.4.5 Relationship between Change in Stress, load inGalleries and Convergence in the PanelThe recordings obtained from stress cells installed inpillars, convergence in galleries and load cells over O.C.props in galleries of Panel-3B are shown in Fig. 12.All the instruments recording values shown increasingwith respective area of extraction in the panel-3B.Generalisation of relationship between stress change inthe panel, convergence in galleries and loads on supportsmay require further studies. Establishing such relationshiphelps in safely working of the panel.Further study revealed that the panel experienced heavyspalling and supports displacements in galleries of66AL North, 66BL North, 67L and 67AL South as shownin Fig. 13 (a, b, c & d).Percentage (%)100806040200Convergence in galleries Load on supports Stres change in the panel0 2000 4000 6000 8000 10000 12000area of excavation (m 2 )Fig. 12 : Stress change in the panel, convergence in galleriesand loads on supports in percentage wise in the panel – 3B(a)(b)(c)Fig. 13 : (a, b, c & d) Pillar spalling and support displacements at 66AL to 67L North Pillar(d)Volume 2 No. 1 January 2013

Strata Monitoring Studies in Blasting Gallery Panel During Depillaring Based on Field Instrumentation315. ConclusionsPlanning and execution of BG panels requires detailedaccounting for rock mass characterisation to be inputinitially and predict the actual behaviour of panel extraction.Field instrumentation provides vital information during theextraction process for taking necessary decisions andprecautions to avoid major obstacles during production.Though planning by various modelling studies providesan insight into the behaviour of panel during extraction,the real-time monitoring facilitates retrieval of valuableinformation about the behaviour of galleries, pillars andgoaf. This study involved extensive field instrumentationto understand the behaviour of strata at different locationswithin the panel.Results revealed that the area of extraction was havingan influence on front abutment stresses, convergencein galleries and loads on supports ahead of the face.Further, it was observed that, total increase in frontabutment stress, about 3.04MPa was noticed when thearea of excavation was 6200 m 2 in the panel. Load onO.C. props increased up to 39 t, indicating transfer ofload ahead of face. Galleries experienced maximumcumulative convergence of 151 mm. Convergence in thegalleries increases with respective to area of excavation.Tell-tale extensometers indicates that there was nodeformation of the immediate coal roof which forms themain roof, whereas, high deformation was recorded inconvergence stations may be due to massive sandstonelayers overhang.It may be concluded that when the large overhang ingoaf is present, high stress in pillars, high convergencein galleries, high loads in galleries and spalling in pillarsis expected. The results obtained from field monitoringstudies were quite comparable with the field conditionsin BG panel, like spalling in pillars and displacement ofsupports in galleries. Adoption of field instrumentation inpanels could, therefore, be of significant value in assessingthe behaviour of BG panels during extraction.Acknowledgement: Author is thankful to SCCL forcarrying out the project and sincere thanks are due toDirector, NIRM, for permission to submit the paper injournal.REFERENCES1. Anon, 2012. Coal reserves statistics, Central MinePlanning & Design Institute Limited (CMPDI),http://www.cmpdi.co.in/.2. CMR, 1957. The Coal Mines Regulations. In Kaku (ed.),Dhanbad, Lovely prakashan.3. Das, M. N. 1986. Influence of width/height ratio on postfailure behaviour of coal. International Journal of Miningand Geological Engineering. 4: 79-87.4. Gupta, R. N., Garg, A. K., Mukherjee, K. P., and Singh.B. 1990. Strata control problems associated duringextraction of developed Pillars in Thick Seam by BlastingGallery method. Rock Mechanics Contributions andChallenges, Hustrulid & Johnson (ed.) ISBN 90 61 91123 0.109-117.5. SCCL Internal Report on BG method, 2005.6. NIRM final report. 1999. Study of cavability of roof of 3seam at GDK-10 Incline, RG-111 Area, SCCL.7. Pandey, B. N., Prasad, S. N., Mukherjee, K. P., Tiwary,S., Samanta, S., and Saxena, N.C., 1992. Experiences ofBlasting Gallery method of Thick Seam mining in Jhariaand Ranigunj Coalfield. Proceedings of Symposium onThick Seam Mining, India, 409-421.8. Rajendra Singh, 2004. Staggered development of a thickcoal seam for full height working in a single lift by theblasting gallery method. International Journal of RockMechanics and Mining Sciences, 41, January, pp 745-759.9. Sheory, P. R. 1993. Design of coal pillar arrays andchain pillars. In Hudson (ed.), Comprehensive RockEngineering. Oxford: Pergamon Press, vol. 2, pp.631-670.10. Singh, R., Ahuja, B. P., Guruvaiha, K., and Ramesh,M., 2004. Geo-technical considerations for full heightextraction of a developed Thick Coal seam withstaggered bottom section by Blasting Gallery method.MGMI Trans. 100: 102-116.11. Singh. R., and Kumar. R. 2007. Pillar stability duringunderground mining of the complete thickness of a thickcoal seam in a single lift - Indian experiences. Eberhardt,Stead & Morrison (ed.), pp.1463-1468.Volume 2 No. 1 January 2013

ISRM (India) JournalMr. Devendra K. Sharma assumes THEcharge of Managing Director ofHimachal Pradesh Power Corpn. Ltd.Mr. Devendra Kumar Sharma, has taken over as Managing Director of Himachal PradeshPower Corporation Ltd. (A Govt. of Himachal Pradesh Undertaking) in September, 2012. AsManaging Director of Himachal Pradesh Power Corporation Ltd., he is responsible for planning,development, engineering, construction and organizing funding for 20 hydroelectric projectshaving aggregate installed capacity of 3025 MW.After graduating in Civil Engineering from the University of Indore in 1981, he was awarded theNetherlands Govt. fellowship, in 1982, to pursue Master of Engineering in Water Resourcesfrom the Asian Institute of Technology, Bangkok, Thailand. He has done training in hydropowerplanning and design engineering from Canada (1987), Sweden (1989) and Japan (1994).During the year 1991, he was awarded UNESCO fellowship to complete International PostGraduate Course in Hydrology from the Water Resources Research Institute (VITUKI), Budapest, Hungary. Hedid courses from the International Centre for Hydropower, Trondheim, Norway as NORAD Scholar in ‘Hydropowerand the Environment’ during 1999 and ‘Hydropower Development in the Context of Integrated Water ResourcesManagement’ during 2003.Mr. Sharma has more than 31 years of experience in the field of hydropower in India and abroad. He worked withHimachal Pradesh State Electricity Board in various capacities for approximately twenty four and half years from1982 to 2006 where he was responsible for planning, investigation, design and monitoring of number of hydroelectricprojects like Chamera Stage II (300 MW), Kol Dam (800 MW), Dhamwari Sunda (70 MW), Ghanwi Stage I (22.5 MW),Gaj (10.5 MW), Baner (12 MW) and Thirot (4.5 MW). He has worked on deputation with SJVNL (formerly NJPC)for Nathpa Jhakri Hydroelectric Project (1500 MW) from 1994 to 1997. He worked in Bhutan on Tala HydroelectricProject (1020 MW) for construction of dam, diversion tunnel, coffer dams and power intakes for 6 years from 1997to 2003 where he was awarded “Man of the Year 1999” award for excellence in performance of duties, dedicatedservices and meritorious contribution in the field of hydropower. After returning from Bhutan during the year 2003, hewas responsible for Sawra Kuddu Hydroelectric Project (111 MW) in Pabbar Valley Power Corporation in HimachalPradesh.In order to gain experience of working in private sector, he worked with L&T from 2006 to May, 2010, where hecompleted works of Parbati Stage III (520 MW) and Allain Duhangan (192 MW) Hydroelectric Projects in HimachalPradesh. From May 2010 to September, 2012, he was responsible for Development of Hydroelectric Projects onBOT basis in India and the neighbouring countries.Mr. Sharma has presented 26 technical papers and reports in International Conferences/Seminars in India andabroad. He has visited hydropower plants in Thailand, Norway, Sweden, Canada, Japan, Hungary, Austria, Spain,Portugal, Bhutan and Nepal.Mr. Sharma is life member of various National and International bodies working in the field of hydropower development.He is a member of Governing Council of International Society for Rock Mechanics since 2008 and is Vice Presidentof Indian Society of Rock Mechanics and Tunnelling Technology. He is Governing Council member of TunnellingAssociation of India for the year 2011-13. He has represented in Technical and Organizing Committees of variousInternational and National Conferences organized in the field of hydropower.ISRM (India) wishes him all success for his new assignments.Volume 2 No. 1 January 201332

Influence of Anisotropic Stress Conditions on Design of Development Workings in Bord and Pillar MiningGOVERNING COUNCIL OFINDIAN NATIONAL GROUP OF ISRMFOR THE TERM 2011-201433President• Dr. H.R. Sharma, Chief Technical Principal – Hydro, Tractebel Engineering Pvt. Ltd.Vice President• Dr. R.K. Goel, Chief Scientist, Central Institute of Mining and Fuel Research, Regional Centre, RoorkeeImmediate Past President• Dr. K.G. Sharma, Professor, Department of Civil Engineering, IIT DelhiMembers• Dr. A.K. Dhawan, Chief Consultant, Fugro Geotech Pvt. Ltd.• Mr. D.P. Goyal, Director, Jaiprakash Power Ventures Ltd.• Mr. R. Jeyaseelan, Former Chairman, Central Water Commission• Mr. Pawan Kumar Kohli, General Manager (Civil Design), Himachal Pradesh Power Corporation Limited• Mr. D.M. Kudtarkar, Chief Technology Officer, Hindustan Construction Company Ltd.• Mr. P.K. Mahajan, VSM, Chief Engineer, Directorate General Border Roads• Mr. Ganesh Manekar, Deputy General Manager (Mines), MOIL Limited• Mr. R.N. Misra, Director (Civil), SJVN Limited• Dr. A. Nanda, Deputy General Manager, Engineers India Limited, Sub Surface Projects Division• Mr. A.B. Pandya, Member (D&R), Central Water Commission• Dr. Rajbal Singh, Joint Director (Rock Mechanics), Central Soil and Materials Research Station• Dr. T. Ramamurthy, Visiting Professor, Department of Civil Engineering, Indian Institute of Technology Delhi• Dr. S. Sengupta, Scientist – V & HOD (Geotechnical Engineering Department) and Scientist-in-Charge -Bangalore Unit, National Institute of Rock Mechanics• Mr. D.K. Sharma, Managing Director, Himachal Pradesh Power Corporation Limited• Dr. T.G. Sitharam, Professor, Indian Institute of Science, Department of Civil Engineering• Dr. Manoj Verman, Technical Director, GEODATA India (P) Limited• Mr. R.K. Vishnoi, General Manager (DE&S –Civil), THDC India Ltd.Member Secretary• Mr. V.K. Kanjlia, Secretary, Central Board of Irrigation & PowerTreasurer• Mr. A.C. Gupta, Director (WR), Central Board of Irrigation & Power33Volume 2 No. 1 January 2013

34 ISRM (India) JournalRecent Activities of Indian National Group of ISRMSEMINAR ON “GROUND CONTROL AND IMPROVEMENT”,20-21 SEPTEMBER 2012, NEW DELHIAs part of its activities, CBIP, with the support of theIndian National Group of International Society forRock Mechanics (ISRM, India) and Indian Chapter ofInternational Geosynthetics Society (IGS, India) organizeda Seminar on “Ground Control and Improvement” at CBIPConference Hall, Malcha Marg, Chanakyapuri, New Delhiduring 20-21 September 2012.The objective of the proposed Seminar was to providea forum for discussion and interaction amongst theparticipants about the potentially applicable groundimprovement methods for civil works structures.Lectures/Case Histories on the following topics werepresented during the Seminar:• Characterization of Ground• Preloading and Vertical Drains• In situ reinforcement Techniques• Geosynthetics and their applications in Geotechnical& Geoenvionmental Engineering• Deep Excavation Support Systems• Grouting Techniques: Permeation, Compaction,Infiltration, Jet Grouting, etc.• Landslides & Slope Stabilisation Methods• Soil & Rock Anchors• Liquefaction & Mitigation MethodsThe Seminar was sponsored by PANASIA ProjectConsultancy Pvt. Ltd. & Wassara and co-sponsored byTechFab (India) Industries Ltd.The Seminar was attended by 61 delegates from 24organisations.The Seminar was inaugurated by Mr. S.P. Kakran,Chairman, Central Water Commission. The inauguralVolume 2 No. 1 January 201334

Recent Activities of Indian National Group of ISRM35session was presided over by Dr. H.R. Sharma, ChiefTechnical Principal-Hydro, Tractebel Engineering Pvt. Ltd.and President, Indian National Group of ISRM. Dr. G.V.Rao, Former Professor, Department of Civil Engineering,IIT Delhi and Past President of the Indian Chapter of IGS,addressed the gathering too.Lectures were delivered by the following prominentexperts during the Seminar:• Mr. Michael Beas, Wassara, Sweden• Mr. Shadab .A. Gadhiya, TechFab (India) IndustriesLtd• Dr. M.R. Madhav, JNT University & IIT Hyderabad• Dr. K. Pathak, IIT Kharagpur• Dr. V.M. Sharma, AIMIL Limited• Mr. R.K. Sinha, National Institute of RockMechanics• Prof. G.L. Sivakumar Babu, Indian Institute ofScience• Dr. G.V. Ramana, Indian Institute of TechnologyDelhi• Dr. G. Venkatappa Rao, Sai Master GeoenvironmentalServices P. Ltd.It was concluded that as more and more poor groundconditions were being encountered at many of theinfrastructural development project sites, and posinggeotechnical challenges, the Seminar on the subjectof “Ground Control and Improvement” was aptlychosen. It was stressed that to keep pace with rapidinfrastructure development, the concerned had tobe prepared to meet the emerging geotechnicalchallenges and provide superior and cost effectivesolutions, besides completing the projects in time boundmanner.International Seminar on “Minimizing GeologicalUncertainties and Their Effect on Hydroelectric Projects”,27-28 September 2012, New DelhiThere is a broad feeling that hydroelectric projects takelonger time than the schedule and the delays are commonlyattributed to uncertainties in geological prognostication,without considering the inherent limitations of such studiesand the applied methodologies. Accordingly, in orderto minimize delays, it is mandatory that the geologicaland geotechnical assessments are made with greaterreliability & precision towards establishment of safeand economic projects. It is therefore important to holdtechnical forum to deliberate upon the critical issues inaddressing problems related to geological & geotechnicalconcerns towards finding appropriate solutions toovercome the challenges.In this context, NHPC Limited, in association withCentral Board of Irrigation and Power (CBIP), organizedan International Seminar on “Minimizing GeologicalUncertainties And Their Effect On Hydroelectric Projects”,on 27 and 28 September 2012 at CBIP Conference Hall,Malcha Marg, Chanakyapuri, New Delhi.The prime objective of the seminar was to discuss issuesrelated to improving upon geological interpretations andsupplementation by geotechnical explorations towardsformalizing a comprehensive investigation program aswell as to bring-forth awareness about the technologicaladvancements and their applications.Volume 2 No. 1 January 2013

36 ISRM (India) JournalLighting of Lamp by V.K. KanjliaThe seminar focused on the issues and challenges inintegration of exploratory techniques for improving thereliability of geological assessment, and provided a forumto discuss matters of adoption of appropriate constructionmethodologies supplemented by contractual provisionrelated to geological information and sharing of risks thatare generally issues of concern. During the Seminar,issues related to generating structural geological modelsfor mechanized tunneling sites as well as the selectionof TBM types, specific for the site conditions, werediscussed.Following were the topics proposed for discussions duringthe Seminar:• Integrating Exploratory Techniques for ReliableGeological Assessment• Provisions for Looking Ahead in Critical Areas inConstruction• Importance of Slope Stability in HydroelectricProjects• Role of Geology in Deployment of TBMMore than 140 delegates from India and abroadparticipated in the Seminar.During the Inaugural Session, Mr. D.P. Bhargava, Director(Technical), NHPC Limited, welcomed the dignitaries onthe dais and the participants.Mr. A.S. Bakshi, Chairperson, Central ElectricityAuthority, in his address mentioned that geologicaluncertainties and unexpected strata encountered duringconstruction of tunnels and underground works ofhydropower projects, especially the large ones, result inunforeseen problems, increased quantities of execution,and time & cost overruns. He expressed the hope thatproject developers, contractors, consultants, engineers,suppliers, researchers who were attending the seminarwould be greatly benefited from deliberations regardingthe state-of-art technology and modern methodologyin overcoming challenges occurring due to geologicaluncertainties during the construction of hydroelectricprojects and thus minimize the cost overruns.Mr. Devendra Chaudhry, Additional Secretary toGovernment of India, Ministry of Power, mentioned thatHydro Electric Projects having about 6000 MW potentialwere affected by geological problems at present, andexpressed the hope that the very purpose of the Seminarwould be not just to address a very large interesting andwider range of issues, but the focus should be to addresswhat were the problems in those projects.Volume 2 No. 1 January 2013

Recent Activities of Indian National Group of ISRM37Mr. R.P. Singh, Chairman and Managing Director, SJVNLimited in his address mentioned that when we look backupon the development of Hydro Power in general inour country in the past, it is observed that barring a fewprojects, all of them have suffered significant time andcost over-run and the major reason cited for it is widevariance between geology predicted at the DPR stageand as actually encountered during the construction ofunderground works, and expressed hope that the elitegathering present in the Seminar would be sharing thelatest development in the geological exploration fieldwhich would definitely help all the developers in havingbetter understanding of geology.The keynote address on “Minimizing GeologicalUncertainties and their Effects on Hydroelectric Projects”was delivered by Mr. M. Gopalakrishnan, Former SecretaryGeneral, ICID, before the commencement of the technicalsessions. Mr. M. Gopalakrishnan emphasized need forissues like cost of investigations, time frame required forplanning to Design stage nature of tender documents.He mentioned that the Hydro Power sector should notbe singled out for failures as failures had been observedall over the world and in case of tunnels in other sectorssuch as transportation sector.The presentations on the following topics were made anddiscussed during the Seminar:• Geological Investigations – Challenges & Success -Mr. A.S. Walvekar, Executive Director (Geo-Tech),NHPC Limited• Geotechnical Monitoring-Contribution to RiskManagement - Dr. Florian Krenn, Managing Director,Geoconsult India Pvt. Ltd.• Optimum Exploration for a Bankable Detailed ProjectReport - Mr. Prasanta Mishra, Director, GeologicalSurvey of India• Importance of Rock Mechanic Studies in SiteCharacterization towards Minimizing Uncertainties -Dr. V. M. Sharma, Director, AIMIL Ltd.• Prognostic Geological Explorations forMinimizing Geological Uncertainties - Dr. GopalDhawan, Chairman and Managing Director, MineralExploration Corporation Limited• Minimizing Geological Uncertainties during theExecution Phase - Mr. Wolfgang Holzleitner, COO,Bernard Gruppe, Germany• Integrating Exploration and Preparation of BaselineReport - Dr. Dinesh Sati, Consulting Geologist, THDCIndia Limited• Geological Assessment through Integrated Approach– Mr. Umesh.V. Hegde, Executive Director-Engg.Geology & Geotech, Lanco Infratech Limited• Geological Uncertainties-Site Specific Challenges andits Management - Mr. Manoj Basu, General Manager(Geology), NHPC Limited• Contractual Problems due to Geological Uncertaintiesand Possible Remediation through Contract – Mr. V.K.Kapoor, President-Projects, Bhilwara Energy Ltd.Volume 2 No. 1 January 2013

38 ISRM (India) Journal• Managing Risk due to Geological Uncertainties inHydropower Projects - Mr. Eckhard Kleine, SalesEngineer, Herrenknecht AG, Germany• Geological Prognostication during MechanizedTunneling – Dr. G.W. Bianchi, Senior EngineeringGeologist, SEA Consulting s.r.l.• Application of Tunnel Seismic Prediction in VariedGeological Conditions - Dr. T. Dickmann, UnitManager-Geophysics, Amberg Technologies AG,Switzerland• Minimizing Geological Uncertainties throughMitigating Measures at Nathpa-Jhakri Project – Mr.Deepak Nakhasi, General Manager (Civil Design),SJVN Limited• Geotechnical Prognostication during Construction –Dr. Rajbal Singh, Scientist, Central Soil and MaterialsResearch Station• Role of Geology and Special Rock Mechanic Tests inTBM Tunnelling-A Perspective – Dr. V.M.S.R. Murthy,Professor, Department of Mining Engineering, IndianSchool of Mines• Concurrent Evaluation & Measures Adopted WhileTunneling Through TBM – Mr. Michele A. Sposetti,India Projects Coordinator, S.E.L.I. Tunnelling (India)Private Limited• Important Aspects for Geological Assessment in TBMSelection- Case history - Mr. M.M. Madan, Director,GVK Group• Current Practices in Ground Improvement and supportMeasures in TBM driven Tunnels through DifficultGeological Conditions - Mr. James Clark, ProjectsManager India, The Robbins Company• Slope Stability-Issues and Management – Mr. BalrajJoshi, General Manager, NHPC Limited• Identification of Potential Slides and Support Systems– Dr. R. Chitra, Scientist, Central Soil and MaterialsResearch StationThe Seminar concluded with Panel Discussions, withfollowing panel of experts:• Dr. H.R. Sharma (Chairman), Chief TechnicalPrincipal-Hydro, Tractebel Engineering Pvt. Ltd.• Dr. V.M. Sharma, Director, AIMIL Ltd.• Dr. Prabhas Pande, Former ADG, Geological Surveyof India• Mr. R.N. Misra, Director (Civil), SJVN Ltd.• Dr. Florian Krenn, Managing Director, GeoconsultIndia Pvt. Ltd.• Mr. A.S. Walvekar, Executive Director (Geotech.),NHPC Ltd.The panel of experts after having an overview of alltechnical sessions initiated discussions within the house.Subsequent to various deliberations in the open house,draft recommendations were made.Seminar on “Slope Stabilization Challenges inInfrastructure Projects”,29-30 November 2012, New DelhiAs part of its activities, the Central Board of Irrigation &Power (CBIP), with the support of the Indian NationalGroup of International Society for Rock Mechanics (ISRM,India) and Indian Chapter of International GeosyntheticsSociety (IGS, India) organised a Seminar on “SlopeStabilization Challenges in Infrastructure Projects” atCentral Board of Irrigation and Power, Malcha Marg,Chanakyapuri, New Delhi on 29 and 30 November2012.The objective of the proposed Seminar was to provide aforum for design and construction engineers for analyzingthe stability of slopes of earth and rock-fill dams, slopesof other types of embankments, excavated slopes, andnatural slopes in soil and soft rock, methods for analysisof slope stability, strength tests, analysis conditions, andfactors of safety, use of geosynthetics for slope stability,etc.The Seminar was inaugurated by Mr. R. Jeyaseelan,Former Chairman, Central Water Commission. TheInaugural Session was presided over Dr. T. Ramamurthy,Visiting Professor, Department of Civil Engineering, IITDelhi.Mr. A.C. Gupta, Director (WR), CBIP, in his welcomeaddress stressed on the need to provide adequatedrainage which, in general, shall help in minimizing failureof soil/rock slopes. He requested participants to haveuseful interaction during the Seminar.Dr. A.K. Dhawan, Chief Consultant, Fugro Geotech Pvt.Ltd., and Former Director, Central Soil and MaterialsResearch Station and Seminar Coordinator brieflydescribed the objectives of the Seminar during theInaugural Session.Volume 2 No. 1 January 2013

Recent Activities of Indian National Group of ISRM39A view of the dais during inaugural session (L to R):Dr. A.K. Dhawan, Dr. T. Ramamurthy, Mr. R. Jeyaseelanand Mr. A.C. GuptaIn total, 40 participants from 26 organizations participatedin the Seminar.Following papers were presented and discussed duringthe Seminar:• Slope Stability - Lesson from Failures Encountered –Mr. R. Jeyaseelan, Former Chairman, Central WaterCommission• Stability Problems in Natural and Manmade Slopes– Dr. A.K. Dhawan, Chief Consultant, Fugro GeotechPvt. Ltd., and Former Director, Central Soil andMaterials Research Station• Role of Geoinformatics in Slope Stability Assessmentand Monitoring – Dr. P.K. Champati Ray, Head,Geosciences and Geohazards Department, IndianInstitute of Remote Sensing, ISRO, Dehradun• Slope Stability in Open Pit Mines- Theory and Practice– Dr. V.K. Singh, Deputy Director & Head, SlopeStability Division, Central Institute of Mining & FuelResearch• Geosynthetic Hybrid Drain System for ImprovingFine Grained Soil – Dr. Chandan Ghosh, Professor& Head (Geohazards), National Institute of DisasterManagement• Slope Stability using Gabions and related FlexibleEngineering Materials – Ms. Minimol Korulla, ChiefTechnical Officer, Maccaferri Environmental SolutionsPvt. Ltd.• Slope Stabilization Challenges - Significance ofAnalysis for Effective Solutions – Mr. R.K. Vishnoi,AGM, THDC India Limited• Stability Analysis of Slopes – Dr. R. Chitra, ScientistE, Central Soil and Materials Research StationPanel Discussions (L to R): Mr. S.K. Raina, Mr. J.N.L. Das,Dr. T. Ramamurthy, Mr. R.K. Vishnoi and Mr. A.C. Gupta• Design and Development of Improved Varieties ofOpen Weave Jute Geotextiles for Erosion Control –Mr. P.K. Choudhury, In-Charge, Geotech Cell, IndianJute Industries’ Research AssociationThe Seminar concluded with the panel discussions on30 November 2012 under the Chairmanship of Prof.T. Ramamurthy. Mr. S.K. Raina, Executive Director,Chenab Valley Power Projects (P) Limited, Mr. J.N.L.Das, Chief Track Engineer, Ministry of Railways Mr.R.K. Vishnoi, AGM, THDC India Ltd. and Mr. A.C.Gupta, Director (WR), CBIP, participated in the PanelDiscussions as panelist. During the session, participantsdiscussed the problem being faced in the professionalengagements and provided their feedback about theSeminar.Some of the points which emerged during the deliberationsof the Seminar are as under:• Construction of any infrastructure in a slide prone areashould be carried out only after gathering enoughgeological data of that area. A powerful databasecomprising of information about disaster prone hillranges should be maintained• Keeping in view that at DPR stage it may not possibleto do the requisite or adequate investigation of soil/rock mass due to various site constraints or someother reasons, it is desirable that during executionwherever there is element of doubt, rock strata or soilmass is to be tested for the requisite properties so asto take mid course correction for slope stabilizationmeasures.• Surface as well as sub-surface Drainage are the bestpreventive measure for mitigation rock/soil slideVolume 2 No. 1 January 2013

40 ISRM (India) JournalA view of the participants• Deep drainage holes are preferred over weep holes inretaining walls for effective slope stabilization. Providingproper drainage measure is key to success.• Roots of Vegetation form an anchor for soil and helpreduce amount of water in pore spaces. Aforestationshould be encouraged to as it can help in slopestabilization. under all conditions.• Mapping of old slide zones using remote sensing datashall be useful for taking preventive action as theseslides can activate any time and may cause heavydamage to man and properties. Geoinformatics toolsand technique(GIT) can supplement the traditionalmethods of observation by providing timely andreliable information at relatively lower cost• Flexible retaining walls using gabions are useful andoften preferable over non flexible retaining walls forslope stabilization.• HYBRID system consisting of thin sand mat at bothsides of geocomposite is found to be efficient againstclogging.• Jute Textile (JGT) plays a more effective role inrestraining surface soil erosion than the conventionalvarieties of Open Weave Jute Geotextile (OWJGT)of identical weights.• Man-made GTs appears to be less effective becauseof its thinness apart from its inability to create acongenial micro-climate that facilitates vegetationgrowth.• For Open cast mining, it is desirable from slopestability considerations to dump the waste material ata safe distance rather than at the top level near thecut slope.ISRM SPONSORED FORTHCOMING EVENTS• 20-22 May, 2013, Brisbane, Australia - Effective and Sustainable Hydraulic Fracturing - anISRM Specialized Conference• 18-20 June 2013, Shanghai, China - SINOROCK 2013 - Rock Characterization, Modelling andEngineering Design Methods – an ISRM Specialized Conference• 20-22 August 2013, Sendai, Japan - The 6th International Symposium on Rock Stress - anISRM Specialized Conference• 21-26 September 2013, Wroclaw, Poland - EUROCK 2013 - Rock Mechanics for Resources,Energy and Environment - the 2013 ISRM International Symposium• 26-28 May 2014, Vigo, Spain - EUROCK 2014 - Rock Engineering and Rock Mechanics:Structures in and on Rock Masses – an ISRM Regional Symposium• 15-17 October 2014, Sapporo, Japan - ARMS 8 - 8th Asian Rock Mechanics Symposium - The2014 ISRM International Symposium• 10-13 May 2015, Montréal, Canada - ISRM 13th International Congress on Rock Mechanics7-9 October 2015, Salzburg, Austria -• EUROCK 2015 – Geomechanics Colloquy - an ISRMRegional SymposiumVolume 2 No. 1 January 2013

ISRM NEWS41ISRM 50-years anniversary celebrations closed inOctober in Salzburg, at the Geomechanics ColloquyThe celebrations of the 50-years anniversary of theISRM started in October 2011 in Beijing, during the12th ISRM Congress, had a peak during the EUROCK2012 in Stockholm, last May, and symbolically closed inOctober 2012 during the 61st Geomechanics Colloquyin Salzburg, the same city where ISRM was founded,in 1962.A number of activities took place during this year ofcelebrations:• A competition, open to ISRM members, to create the50th anniversary logo, which was used throughout theyear of 2012, won by our member Dr Ludger Suarez-Burgoa.• A competition open to young members of the ISRMto present their vision of “The Future Directions forEngineering Rock Mechanics”, won by Dr RicardoResende.• A 50th anniversary commemorative banquetheld during the ISRM Congress in Beijing on 21October 2011, where Dr Nuno Grossmann made apresentation on the life of the Society during its first50 years.• The publication of the “ISRM 50th AnniversaryCommemorative Book - 1962-2012”, edited byProf. John Hudson and Dr Luís Lamas. Thisbook has been compiled to celebrate ISRM’s50-year anniversary by outlining the backgroundto the formation of the ISRM and the mostsignificant activities during the 50 years. It includescontributions from the living Past Presidents of theISRM and from the Regional Vice Presidents. Thisfull colour book, with 200 pages, can be purchasedfrom the ISRM Secretariat.• A Historical Exhibition including six panels describingthe main milestones in the development of the ISRMduring these 50 years, starting with the constitutionalmeeting on 25 May 2012 in Salzburg and theFirst Congress in Lisbon in 1966. Reference ismade to the main technical achievements, namelythrough the ISRM Commissions and Congresses,to the most important publications and to the maintechnical concerns of the Society along the years.The evolution of the membership and the locationof the venues of the ISRM conferences are alsopresented.• The Commemorative Book and the HistoricalExhibition were displayed at all the ISRM conferencesof 2012, at the 46th U.S. Rock Mechanics Symposiumand also at the 61st Geomechanics Colloquy, inSalzburg.• A commemorative session at the GeomechanicsColloquy in Salzburg, with the presence of Dr FranzPacher, one of the founders of the ISRM,Closing session of the 50th anniversary celebrations inOctober 2012, in Salzburg, during the 61st GeomechanicsColoquy: addresses by Prof. Wulf Schubert, Dr NunoGrossmann and Prof. Xia-Ting Feng.Dr Franz Pacher—that together with Prof. Leopold Müller putforward the idea of creating the ISRM—gave an interviewallusive to the foundation of the ISRM and was presentat the commemorative ceremony.Volume 2 No. 1 January 2013

42 ISRM (India) JournalA Tribute to John Franklin, 1940-2012Professor John Franklin passed away on 6 July, after aprolonged illness that he fought with unparalleled strengthand courage. Those who attended the ISRM Congress inBeijing, last October, where John received his Fellowshipof the ISRM, can confirm his perseverance and dedicationto our Society until the limit of his capacities.For the Geo-engineering communityand for the ISRM in particular this is avery sad moment. Geo-engineeringat large is poorer. John Franklinwas a top scientist, a successfulpractitioner, a strong leader and amarvelous person. Those who hadthe privilege to know him will neverforget his dedication, his capacity tomotivate people, his brilliant mind and his insurmountablecapacity to discover new research themes, or new workingmethods. He was and will remain a guide for youngergenerations.Of his lifetime accomplishments, he was most proud of hisassociation with the ISRM. He served as ISRM President(1987-1991) and Chairman of the ISRM Commissions onTesting Methods (1975-1987) and Education (1991-1995).Among his uncountable contributions to our Society, Johnhas organised and directed the preparation of most of theISRM “Suggested Methods” for rock testing.ISRM Franklin Lecture instituted to honour thememory of late Past President Professor JohnFranklinThe ISRM Board decided to institute the ISRM FranklinLecture to honour the memory of Professor John Franklin(1940-2012), President of the International Societyfor Rock Mechanics from 1987 to 1991. Among hisuncountable contributions to our Society, John Franklinhas organised and directed the preparation of most of theISRM “Suggested Methods” for rock testing.The purpose of the ISRM Franklin Lecture is to recognisea mid-career ISRM member who has made a significantcontribution to a specific area of rock mechanics and/or rock engineering. It will be given in every year, at theISRM International Symposium, except for those yearswhen the 4-yearly ISRM Congress is held. This lecturewill replace the existing ISRM annual lecture.Click here to read the Guideline for the FranklinLecture.The ISRM Franklin Lecturer will be selected by theBoard. He shall be based in the region where the ISRMInternational Symposium is being held that year, and willbe required to give a keynote presentation on the subjectof his/her expertise.The ISRM Franklin Lecture will be published in the ISRMNews Journal.The 2013 ISRM Franklin Lecture will be given in Wroclaw,Poland, during the 2013 International Symposium, byDr. Andreas Goricki from Austria.A massive Global Energy Assessment Study InvolvedExperts from Around the WorldThe International Institute for Applied Systems Analysis(IIASA) in Austria has completed a massive GlobalEnergy Assessment study involving experts from aroundthe world. The report is available for downloading at thefollowing site: http://www.iiasa.ac.at/web/home/research/researchPrograms/Energy/Chapters_Home.en.html.One of our ISRM Members, Dr Maurice Dusseault, andhis graduate student Ali Shafiei, contributed importantsections related to nonconventionalpetroleumenergy sources, with a focuson viscous oil productionmethods and environmentalissues. Dr Dusseault ist h e P r e s i d e n t o f t h ePetroleum GeomechanicsCommission of the ISRM,and the contributions thathe has made to heavy oildevelopment engineeringhave been related to histraining and experience inRock Mechanics.Dr Dusseault and Ali Shafiei also recently contributed anew Chapter on Oil Sands for the well-known Ullmann’sEncyclopedia of Industrial Chemistry, an industrystandard knowledge base published by Wiley: DusseaultMB, Shafiei A. 2011. Oil Sands. Ullmann’s Encyclopediaof Industrial Chemistry, Wiley-VCH Verlag GmbH & Co.KGaA, Weinheim. 52 pages. This chapter evaluates worldoil sand resources and summarizes many aspects ofresource magnitude and production approaches.Maurice DusseaultGo to the top of the NewsletterISRM Online Lectures Series: A New Initiative to Startin February 2013The ISRM Board has discussed a number of initiativesto be implemented in the short term, in order to givemore benefits to the members and to serve better theVolume 2 No. 1 January 2013

43rock mechanics community. One ofthem, which will start very soon, isthe ISRM Online Lectures Series.Experts in different fields of rockmechanics will be invited to givea lecture on a specific topic. Eachlecture will be broadcast from theISRM website at a predefined dateand time, and the attendees willbe able to ask questions to thelecturer by e-mail, on the topic of the lecture, during thesubsequent 48 hours. The ISRM Online Lectures willremain available on the ISRM website in a dedicatedwebpage.Our plans are to organise four Online Lectures per year.The first one will be broadcast on 19 February, at 10 a.m.GMT, and it will remain online so that those those unableto attend at this time will be able to do it later. In orderto know what is the correspondence between GMT andyour local time, just look for GMT in your Internet searchengine.For the first Online Lecture the ISRM President decided thatit would be a good opportunity to listen to the developmentsin the well-known New Austrian Tunnelling Method, nowthat it formally completed 50 years of existence. Theinvited speaker will be Prof. Wulf Schubert from Austria,and the title of his lecture will be “50 years NATM - from aconstruction method to a system”.Prof. Schubert is head of the Institute for Rock Mechanicsand Tunnelling at the Graz University of Technology,where he teaches in the Bachelor and Master program,as well as in the post-graduate course “NATM Engineer”.Under his guidance about 70 Master theses and 20 PhDtheses have been prepared. Besides the Universityactivities he consults on international projects as a partnerof 3G - Gruppe Geotechnik Graz Consulting Engineers.He served as Vice President at Large for the ISRM from1999 to 2003 and is President of the Austrian Society forGeomechanics since 2007.New Delhi Asian Rock Mechanics SymposiumKeynote Lectures Now OnlineThe videos and presentations of the keynote lectures ofthe 2010 ARMS held in New Delhi, India are now online.ISRM members can watch the full length lectures, whichare accompanied by the powerpoint presentations:• Jan Christer Andersson, Rocha Medal Winner - ÄspöPillar Stability Experiment• John A. Hudson - Underground Radioactive WasteDisposal: The Rock Mechanics Contribution• Maurice Dusseault - Deep Injection Disposal:Environmental and Petroleum Geomechanics• Shinichi Akutagawa - On Site Visualization as aNew Paradigm for Field Measurement in RockEngineering• Herb Wang - Deep Underground Instrumentation andMonitoring• Giovanni Barla - Progress in the Understanding ofDeep-Seated Landslides from Massive Rock SlopeFailure• Yossef H. Hatzor - Modelling Dynamic Deformationin Natural Rock Slopes and Underground Openingswith Numerical DDA Method• Claus Erichsen - Challenges in the Design andConstruction of Tunnels in Jointed Rock• Guowei Ma and Yingxin Zhou - Rock DynamicsResearch in Singapore: Fundamentals andPractices• Xia-Ting Feng - Application of Intelligent RockMechanics Methodology to Rock Engineering• John Read - The Large Open Pit ProjectWudongde Hydropower Station - A New 10,200 MWHydropower Project• The Wudongde hydropower station, located at thedownstream segment of Jinsha River has an installed10,200MW electric capacity. It consists of one damand two underground cavern hinges. The dam isa typical hyperboloidal arch concrete dam with themaximum height in 265m. There are five table holes,six mid holes and two spillway tunnels in this dam.• The left underground hydraulic caverns includemain powerhouse, main transformers cavern, sixbusbar tunnels, tailwater lock chamber, six pressurepipes, and six tailwater tunnels. The size of mainpowerhouse is about 321.0m in length, 31.8m in widthVolume 2 No. 1 January 2013

44 ISRM (India) Journaland 86.9m in height. The main transformers cavern,which is parallel to the main powerhouse and is 45min distance with main powerhouse, is about 255.6m inlength, 18.5m in width and 34.5m in height. The axesdirection of main powerhouse and main transformerscavern is NE42º in trend, which intersects the trendof rock stratum with 45º. The underground hydraulichinge in right bank has the same structure of leftunderground hydraulic. The axes direction of mainpower and main transformed cavern is NE70º, whichintersects the trend of rock stratum with 10º.• The rock stresses around the left and groundunderground caverns is shown in the followingtable.Fig. 1 : Layout of Wudongde hydraulic projectUndergroundcavernsLeftRightStatisticValue(MPa)Range 11.3-14.9Principal stressDip angle(°)Trend angle(°)40-70210-270Value(MPa)5.2~8.2Principal stressDip angle(°)Max. 14.9 68 9.6 41Min. 11.3 7 5.2 5Average 13.3 41.4 6.8 24.6Range 5.6-13.0290-340120-180Max. 13.0 88 6.4 80Min. 5.6 4 2.9 2Average 7.2 56.9 4.0 12.9Trend angle(°)300-340120-14050-100300-360• The folded stratum in this region is slight metamorphiclimestone and marble and sedimentary dolomite withthe dip angle of 50~80º, as can be seen in Fig.3.Thus, during the excavation of underground tunnels orcaverns, falling of surround rock occurred frequently,as shown in Fig.4.Fig.2 : The Jinsha River and bankscollapse in the diversion tunnelFig.3 : Steep dip stratum in diversiontunnelFig.4 : RockVolume 2 No. 1 January 2013

45The 2014 ISRM International Symposium will takeplace in JapanThe ISRM Council has selected Sapporo, Japan, asthe venue of the 2014 ISRM International Symposium,following a vote by secret ballot between Eurock 1014 inVigo, Spain, and ARMS 8.ISRM Rocha Medal 2013The ISRM Board decided at its Tokyo meeting inSeptember 1981, to institute an annual prize with aview to honour the memory of Past-President Prof.Manuel Rocha. Profiting from the basis establishedby Prof. Müller, Prof. Rocha organized the first ISRMCongress and he was the leader that was responsiblefor transforming the international collaboration carriedout in an amateurish way into a real internationalscientific association, having for the purpose settled thefundamental lines that have guided and supported theISRM activity along the years.The Rocha Medal is intended to stimulate youngresearchers in the field of rock mechanics. Theprize, a bronze medal and a cash prize, have beenannually awarded since 1982 for an outstandingdoctoral thesis selected by a Committee appointed forthe purpose.The ISRM Board has decided to award the Rocha Medal2013 to Dr Mathew Pierce from Canada for the thesis“A model for gravity flow of fragmented rock in blockcaving mines” presented at the University of Queensland,Australia. He will receive the award at the 2013 ISRMInternational Symposium in Wroclaw, Poland.Two runner-up certificates were also awarded to DrHe Lei, from China, for the thesis “Three dimensionalnumerical manifold method and rock engineeringapplications” presented at the Nanyang TechnologicalUniversity, Singapore, and to Dr Andrea Perino, from Italy,for the thesis “Wave propagation through discontinuousmedia in rock engineering” presented at the Politecnicodi Torino, Italy.“Hydrogeology for Rock Engineers” by GunnarGustafson published by BeFo with ISRMsponsorshiThe book “Hydrogeology for Rock Engineers” by GunnarGustafson, originaly written in Swedish, was translatedinto English and published by BeFo, the SwedishRock Engineering Research Foundation, with ISRMsponsorship. The book can be purchased from BeFo.Groundwater has become a problem in construction oftunnels and other underground facilities in a way it hasnever been before. Tighter environmental regulationsmean that documentation of a completely differentcalibre is now required when applying for permission toconstruct an underground facility. Greater requirementsfor a dry environment in road and railway tunnelshave increased demands on sealing and drainage.Existing tunnels in metropolitan areas largely drainthe rock of the available groundwater, and new undergroundconstructions and tunnels can exacerbate thesituation. Naturally, the traditional problems relating togroundwater remain, making construction difficult inwater-conducting zones in poor-quality rock, and involvingthe risk of settlement if clay layers overlying the rockare drained.This book provides a review of our current knowledgeabout the hydro-geology of the crystalline basement, andexplains how this can be applied in practical methods foruse in site investigations, layout and design, as well asin the operation of tunnels and underground facilities.The work is based on research and practical experienceof hydrogeological problems and phenomena. Much ofthe knowledge base comes from the SKB research andpre-investigation studies relating to final disposal forspent nuclear fuel. However, the aim is not to describethe research front as such, but rather to explain what isimportant and useful for the rock construction communityin general.ISRM CommunicationThe website continues to be the main source ofinformation about the Society and most benefits areoffered to the members in a password protected members’area. Members can now download their membershipcertificates in pdf format.The digital newsletter is sent to all ISRM members andsubscribers every 3 months. It includes news about thesociety and other news of interest to rock mechanics.Contributions are welcome with short news on issues ofgeneral interest.The latest issue of the News Journal, edited by Prof.John Hudson and Prof. Xia-Ting Feng, has 80 pagesand contains the annual review of the Society’s activityalong 2011 and technical articles such as a summaryof the 6th Müller Lecture. It has been posted on thewebsite where it can now be read online or it can bedownloaded.The Digital Library, hosted by OnePetro.org, continuesto be updated with papers from more ISRM sponsoredconferences. It has now 22 conferences, with over 25,000pages. Members can download 100 papers per year atno cost.Volume 2 No. 1 January 2013

46 ISRM (India) JournalRecipients of the Rocha Medal1982 A.P. Cunha PORTUGAL Mathematical Modelling of Rock Tunnels1983 S. Bandis GREECE Experimental Studies of Scale Effects on Shear Strength and Deformationof Rock Joints1984 B. Amadei FRANCE The Influence of Rock Anisotropy on Measurement of Stresses in Situ1985 P.M. Dight AUSTRALIA Improvements to the Stability of Rock Walls in Open Pit Mines1986 W. Purrer AUSTRIA Calculation Model for the Behaviour of a Deep-Lying Seam Roadway ina Solid (but cut by Bedding Planes) Surrounding Rock Mass, taking intoConsideration the Failure Mechanisms of the Soft Layer Determined In-Situ on Models1987 D. Elsworth UNITED KINGDOM Laminar and Turbulent Flow in Rock Fissures and Fissure Networks1988 S. Gentier FRANCE Morphology and Hydromechanical Behaviour of a Natural Fracture in aGranite, under Normal Stress – Experimental and Theoretical Study1989 B. Fröhlich GERMANY Anisotropic Swelling Behaviour of Diagenetically Consolidated Claystones1990 R.K. Brummer SOUTH AFRICA Fracturing and Deformation at the Edges of Tabular Gold MiningExcavations and the Development of a Numerical Model describing suchPhenomena1991 T. H. Kleine AUSTRALIA A Mathematical Model of the Rock Breakage by Blasting1992 A. Ghosh INDIA Fractal and Numerical Models of Explosive Rock Fragmentation1993 O. Reyes W. PHILIPPINES Experimental Study and Analytical Modelling of Compressive Fracture inBrittle Materials1994 S. Akutagawa JAPAN A Back Analysis Program System for Geomechanics Application1995 C. DerekMartinCANADAThe Strength of Massive Lac du Bonnet Granite around UndergroundOpenings1996 M. P. Board USA Numerical Examination of Mining-Induced Seismicity1997 M. Brudy GERMANY Determination of In-Situ Stress Magnitude and Orientation of 9 km Depthat the KTB Site1998 F. MacGregor AUSTRALIA The Rippability of Rock1999 A. Daehnke SOUTH AFRICA Stress Wave and Fracture Propagation in Rock2000 P. Cosenza FRANCE Coupled Effects between Mechanical Behaviour and Mass TransferPhenomena in Rock Salt2001 D. F. Malan SOUTH AFRICA An Investigation into the Identification and Modelling of Time-DependentBehaviour of Deep Level Excavations in Hard Rock2002 M.S.Diederichs2003 L. M.AndersenCANADASOUTH AFRICAInstability of Hard Rockmasses: the Role of Tensile Damage andRelaxationA Relative Moment Tensor Inversion Technique applied to SeismicityInduced by Mining2004 G. Grasselli ITALY Shear Strength of Rock Joints based on the Quantified SurfaceDescription2005 M. Hildyard UNITED KINGDOM Wave Interaction with Underground Openings in Fractured Rock2006 D. Ask SWEDEN New Developments of the Integrated Stress Determination Method andApplication to the ÄSPÖ Hard Rock Laboratory, Sweden2007 H. Yasuhara JAPAN Thermo-Hydro-Mechano-Chemical Couplings that Define the Evolution ofPermeability in Rock Fractures2008 Z.Z.Liang CHINA Three Dimensional Numerical Modelling of Rock Failure Process2009 Li Gang CHINA Experimental and Numerical Study for Stress Measurement by JackFracturing and Estimation of Stress Distribution in Rock MassVolume 2 No. 1 January 2013

472010 J. ChristerAnderssonSWEDENRock Mass Response to Coupled Mechanical Thermal Loading. ÄspöPillar Stability Experiment, Sweden2011 D. Park KOREA Reduction of Blast-Induced Vibration in Tunnelling Using Barrier Holesand Air-deck2012 M.T. Zandarin ARGENTINA Thermo-Hydro-Mechanical Analysis of Joints - A Theoretical andExperimental StudyRocha Award Runner Up Certificates2010 Yoon Jeongseok KOREA Hydro-Mechanical Coupling of Shear-Induced Rock Fracturing by BondedParticle Modeling2010 Abbas Taheri IRAN Properties of Rock Masses by In-situ and Laboratory Testing Methods2011 Bo Li CHINA Coupled Shear-flow Properties of Rock Fractures2012 B.P Watson SOUTH AFRICA Rock Behaviour of the Bushveld Merensky Reef and the Design of CrushPillars2012 J. Taron USA Geophysical and Geochemical Analyses of Flow and Deformation in FracturedRockNews from Indian National Group of ISRMNOMINATION FROM INDIA FOR ISRM COMMISSION ON EDUCATIONISRM Commission on "Education" is one of the commissions on various subjects. The purpose of the Commissionis to organize activities and enhance teaching and training level of education on rock mechanics.Prof. Meifeng Cai, College of Resources Engineering, University of Science & Technology Beijing, is the Presidentof the Commission. The other members of the commission are:= M. A. Kwasniewski (Poland)= N. F. Grossmann (Portugal)= M. U. Ozbay (USA)= J.P. Harrison (Canada)= J.A. Wang (China)= F. Pellet (France)= L. Jing (Sweden)= J. Zhao (Switzerland)= Xia-Ting Feng (ex officio), ISRM President= Yingxin Zhou (ex officio) ISRM Vice President (Asia)ISRM requested the Indian National Group to nominate a key person who is working at Indian University to be amember of ISRM Commission on Education.Prof. K.G. Sharma, Department of Civil Engineering, IIT Delhi, has been nominated as member of the Commission fromIndia considering his exposure to teaching of rock mechanics, both at Undergraduate and Postgraduate levels.Volume 2 No. 1 January 2013

48 ISRM (India) JournalPUBLICATIONS OF INDIAN NATIONAL GROUP of ISRMProceedings of the 6 th Asian Rock MechanicsSymposium on “Advances in Rock Engineering”India is a fast developing economy requiring large scaleinfrastructure. Successive five year plans of Governmentof India have provided the policy frame work and fundingfor building up its wide infrastructure and manpowerRock Engineering does play an important role in mostof infrastructure developmental activities related tocivil engineering works. The need therefore is to keepourselves abreast with the latest development in the fieldof rock engineering and its related fields such as designand construction of underground works, foundation ofdams, slope stability etc.Keeping this in view, ISRM International Symposium andthe 6 th Asian Rock Mechanics Symposium on “Advancesin Rock Engineering” was jointly organized by the IndianNational Group of ISRM and Central Board of Irrigationand Power, in New Delhi during 25-27 October 2010.The proceedings of the Symposium contains extendedabstracts of 166 papers from 27 countries selected fororal and poster presentations on the following topics:• Testing and Modelling of Rocks & Rock Masses• Slope Stability: Analysis & Design• Foundations• Underground Structures: Analysis, Design &Construction• Artificial Intelligence• Flow and Contaminant Transport• Rock Dynamics• Techniques for Improvement of Quality of RockMass• Instrumentation and MonitoringIn addition, the proceedings contains the full texts of thefollowing keynote lectures delivered by renowned expertsfrom Australia, Canada, China, Israel, Italy, Japan,Singapore, U.K. and USA:• On Site Visualization as a New Paradigm for FieldMeasurement in Rock Engineering• Progress in the Understanding of Landslides fromMassive Rock Slope Failure• Deep Injection Disposal: Environmental andPetroleum Geomechanics• Application of Intelligent Rock Mechanics Methodologyto Rock Engineering• Modelling Dynamic Deformation in Natural RockSlopes and Underground Openings with NumericalDDA Method• Underground Radioactive Waste Disposal -- The RockMechanics Contribution• Rock Dynamics Research in Singapore: Fundamentalsand Practices• The Large Open Pit Project• Deep Underground Instrumentation and MonitoringThe full texts are available in electronic version with theextended abstracts in print.Priced at Indian Rs. 1500/US$ 50 + Postage Charges,the proceedings would be very informative and usefulreference to the concerned agencies/individuals.Members of CBIP and ISRM will be offered 10% discount.The proceedings can be purchased by payment throughdemand draft/cheque payable at par in New Delhi, infavour of “Central Board of Irrigation and Power”.Manual on Rock MechanicsThe first Manual on Rock Mechanics, which was preparedunder the guidance of an Expert Committee, was releasedby Central Board of Irrigation & Power (CBIP) in early1979. The manual was very well received.The manual was revised in 1988, to reflect the thenstate-of-art knowledge of Indian Engineers in the field ofRock Mechanics and contained 17 Chapters, coveringbasic concepts of Rock Mechanics, Field and LaboratoryTests on Rock Mass and Rock Specimen, GeophysicalInvestigations, Interpretation of Test Data and theirApplication to various problems of Foundation of Dams,Tunnelling, etc.The Governing Council of the Indian National Group ofISRM felt that there was a need to update the manual,as more than 20 years had passed since its lastpublication.Accordingly, the manual was updated and released duringthe ISRM International Symposium 2010 and 6 th AsianRock Mechanics Symposium held in New Delhi during23-27 October 2010.Volume 2 No. 1 January 2013

GUIDELINES FOR AUTHORSThe authors should submit their manuscript in MS-Word (2003/2007) in single column, doubleline spacing. The manuscript should be organized to have Title page, Abstract, Introduction,Material & Methods, Results & Discussion, Conclusion, and Acknowledgement. The manuscriptshould not exceed 16 pages in double line spacing.Submission of Manuscript:The manuscript must be submitted in doc and pdf to the Editor as an email attachment to uday@cbip.org. The author(s) should send a signed declaration form mentioning that, the matterembodied in the manuscript is original and copyrighted material used during the preparation ofthe manuscript has been duly acknowledged.Peer Review Policy:Review System: Every article is processed by a masked peer review of double blind or bythree referees and edited accordingly before publication. The criteria used for the acceptance ofarticle are: contemporary relevance, updated literature, logical analysis, relevance to theglobal problem, sound methodology, contribution to knowledge and fairly good English.Selection of articles will be purely based on the experts’ views and opinion. Authors will becommunicated within Two months from the date of receipt of the manuscript. The editorial officewill endeavor to assist where necessary with English language editing but authors are herebyrequested to seek local editing assistance as far as possible before submission. Papers withimmediate relevance would be considered for early publication. The possible expectations willbe in the case of occasional invited papers and editorials, or where a partial or entire issue isdevoted to a special theme under the guidance of a Guest Editor.The Editor may be reached at: uday@cbip.org49Volume 2 No. 1 January 2013

ISRM (India) JournalRECOGNITIONSDr. V.K. Singh, Chief Scientist & Head, Slope Stability Department, Central Institute of Miningand Fuel Research, Dhanbad, and an active life member Indian National Group of ISRM, hasbeen awarded with Society of Geoscientists and Allied Technologists (SGAT) Award ofExecellence-2012, in recognition of his outstanding contribution on Geotechnical Services tothe Mining Industry for better management of safety and mineral conservation through ecofriendlymining.Dr. V.K. Singh has been instrumental in confidence building to the civil construction projects inHimalayan Region and control of landslides. His prolific contribution towards development ofindigenous technology and geotechnical contributions to Indian Mining Industry is praiseworthy.His number of scientific publications in reputed international and national journals, differentbooks on technology, has brought outstanding recognition to Dr. V.K. Singh as a true scientist in the field of earthscience with special reference to geotechnical investigations and slope stability studies.Dr. V.K. Singh has initiated, motivated and guided to establish geotechnical laboratories/slope stability cell in variousmining organizations of repute in the country.Indian National Group of ISRM congratulates Dr. V.K. Singh for his outstanding contribution to the Mining Industry,and wishes him to contribute more in future.Dr. Bhandari awarded Prestigious VarnesMedal for 2012Dr R.K.Bhandari was awarded the prestigious Varnes Medal for the year 2012 at the UNESCO Headquarters in Parison 23 November 2012 for excellence in research on Landslides. It is the highest award of the International Consortiumof Landslides (ICL) and Dr. Bhandari is the first Indian recipient. The ICL represents 51 member institutions from 32countries; and its International Programme on Landslides (IPL) was jointly established by UNESCO, WMO, FAO,UNISDR, UNU ICSU, IUGS and WFEO. Dr Bhandari is seen in the above picture with Professor Paolo Canuti, thePresident of ICL (extreme right), Professor Kyoji Sassa the Executive Director of ICL (extreme left) and Dr. SalvanoBriceno, Chair of Science Committee of Integrated Research on Disaster Risk.Volume 2 No. 1 January 2013

Forthcoming Activities of Indian NationalGroup of ISRMInternational Symposium“ROCK MECHANICS INDIA’ 2013 –Present Technology and Future Challenges” andPre-Symposium Workshop on “Open Pit Mining”3-5 July 2013, New Delhi, IndiaINTRODUCTIONThe study of rock mechanics has assumed considerableimportance because of its wide application in civilengineering, more predominantly in water resources,mining engineering and underground structures. For theexecution of multipurpose water resources projects locatedin complicated geological settings, the significance of rockmechanics in the design and construction was realisedin late 1950s. Despite tremendous alround advancementin technology, a full understanding of natural forces andphenomena eludes the design engineer. The details ofthe challenges encountered during construction of waterresources projects in adverse geological conditions andthe methodology/approach followed to reduce them havelot of significance to construction and design engineers.Similar experiences for the design and construction ofroad tunnels, metro tunnel, rail tunnels in complicatedconditions along with stability of slopes will also bevery useful. Mining is another field where besides openpit mining, deep seated ore mining is also providingchallenges to engineers. Besides providing support,instrumentation is also gaining importance as it helpsstudying the moment of rock mass and provide timelywarning to take appropriate action.Both design and construction engineers would alwaysbe keen to know what advancements are taking place intheir respective fields. Therefore, there is a need for upgradation of ones knowledge.Liberalisation of economy has facilitated planning andexecution of many exciting and complicated projectsin India. These projects require application of modernprinciples of rock mechanics, which warrants deliberationsand collaboration to facilitate flow of appropriatetechnology to enable successful implementation of suchprojects under a time-bound programme in a cost-effectivemanner, conforming to environmental requirements.To deliberate on the advances in rock engineering, theIndian National Group of ISRM and the Central Boardof Irrigation & Power (CBIP) are organizing the presentInternational Symposium – Rock Mechanics India’ 2013on “Present Technology and Future Challenges” and Pre-Symposium Workshop on “Open Pit Mining”.SYMPOSIUM SUB-THEMES1. Advancements in Testing and Characterisation ofRocks and Rock Masses2. Modelling and Analysis of Rock Structures3. Preservation and Restoration of Ancient RockMonuments4. Underground Construction and Mining in ProblematicGeological Conditions5. Utilisation of Underground Space including Storageof Water and Gas6. Fracture and Fragmentation7. Stability of Underground and Surface Openings8. Environmental Issues• Special Session on Underground Mining- Underground Mining in Narrow and Wider OreBodies with Different Rock Mass Conditions- Underground Mining at Deep Seated OreBody- Underground Development & Mining in WeakRock Mass Conditions- Instrumentation in Underground Mining forBetter Safety & ProductivityPRE-SYMPOSIUM WORKSHOP - OPEN PIT MININGTopics proposed for discussions:• Instrumentation and Slope Monitoring• Pit Slope Stability in Open Cast Mines• Blasting Practices for Safe Open Pit mining• Groundwater Management51Volume 2 No. 1 January 2013

52 ISRM (India) JournalCALL FOR PAPERS / CASE STUDIESPapers/Case studies on the topics proposed and alliedtopics are invited. The full text of the papers/case studies,not exceeding 08 pages of A4 size, in single space, bothin MS Word and PDF, need to be sent through e-mail onlyat uday@cbip.org.. The last date for the receipt of fulltexts of the case studies is 15 June 2013.The papers/case studies will be reviewed by the TechnicalCommittee as to their suitability for presentations. Thepapers/case studies accepted for presentations will benotified by 22 June 2013. A condition of acceptance ofthe papers/case studies will be that the author, or oneof the authors in case of multiple authors, will attend theSymposium and make the presentation.The paper/case study shall contain:• a descriptive, but brief title• title, name(s) and affiliation of the author(s)• address for correspondence (including fax numbersand e-mail addresses)• detailed information about the objective, methods,results and conclusion, to enable a correct appraisalof the suitability of the proposed paper/case study forthe SymposiumOnly original contributions that have not been publishedor presented at any other forum are acceptable.REGISTRATION FEEA. Pre-Symposium Workshop (3 July 2013)Members of CBIP/ISRM/ITA/ICOLD/IGSIndian Rs. 4,500/-USD 115 + Service Tax@ 12.36%Non-Members Indian Rs. 5,000/-USD 125 + Service Tax@ 12.36%Researchers/Academicians/ Students/Accompanying PersonsIndian Rs. 2,500/-USD 65 + Service Tax@ 12.36%B. Symposium (4-5 July 2013)Members of CBIP/ ISRM/ITA/ ICOLD/ IGSIndian Rs. 9,000/-USD 225 + Service Tax@ 12.36%Non-Members Indian Rs. 10,000/-USD 250 + Service Tax@ 12.36%Researchers/Academicians/StudentsIndian Rs. 5,000/-USD 125 + Service Tax@ 12.36%C. Combined Fee for the Pre-Symposium Workshopand Symposium (3-5 July 2013)Members of CBIP/ ISRM/ITA/ ICOLD/IGSIndian Rs. 12,000/-USD 300 + Service Tax@ 12.36%Non-Members Indian Rs. 13,500/-USD 340 + Service Tax@ 12.36%Student/AccompanyingPersonIndian Rs. 6,500/-USD 165+ Service Tax@ 12.36%In case of 03 or more nominees from an organization, onenomination will be allowed free registration.To avail the student concession in the registration fee,the registration form/request will have to be submittedalong with a certificate from the head of the Department/institute.SYMPOSIUM SECRETARIATCentral Board of Irrigation & PowerMalcha Marg, Chanakyapuri, New Delhi 110 021, IndiaContact Person: V.K. Kanjlia, Member Secretary, IndianNational Group of ISRMPhone : +91-11- 2611 5984/2611 1294Fax : +91-11- 2611 6347E-mail : uday@cbip.org; cbip@cbip.orgWeb : http://www.cbip.orgVolume 2 No. 1 January 2013