A Versatile Rock Melting System For the Formation ... - The Black Vault

LA-5422-MSINFORMAL REPORTA Versatile Rock-Melting System for theFormation of Small-DiameterHorizontal Glass-Lined HolesIosi alamosscientific laboratoryoff the University off CaliforniaLOS ALAMOS, NEW MEXICO 87544\UNITED STATESATOMIC ENERGY COMMISSIONCONTRACT W-740S-ENG. 36DfSTRlBU

This report was prepared as an account of work sponsored by the UiiitedStates Government. Neither the United States nor the United States AtomicEnergy Commission, nor any of their emptoyees, nor any of their contractors,subcontractors, or their employees, makes any warranty, express or implied,or assumes any legal liability or responsibility for the accuracy, completenessor usefulness of any information, apparatus, product or process disclosed,or represents that its use would not infringe privately owned rights.In the interest of prompt distribution, this LAMS reportwas not edited by the Technical Information staff.Printed in the United Slates of America. Available fromNational Technical Information ServiceU. S. Department of CommerceS2PB Port fteyal RoadSpringfield, Virginia 22151Price: Printed Copy S4.00; Microfiche $0.95

LA-5422-MSInformal ReportUC38ISSUED: October 1973scientific laboratoryof »h« Un!v»r*ity of CaliforniaIOS AtAMOS. NEW MtXICO *7S4*A Versatile Rock-Melting Sysfem for fheFormation of Small-DiameterHorizontal Glass-Lined HolesbyD. L. SimsWork supported in part by a grant from the National Science FoundationResearch Applied to National Needs (RANN).-NOTICt-Tlitu icpvrt n-ii picparcd as an account uf worksponsored by the (tailed Slalct Government. Nchticr•he ttnllod Sum mi! I he Itnilcd Stales Atomic KC*4itninbatiin. uwr any uf GhcUs. n^r any ofIticir ci>nirjcl«fii. &ut)c(itttrai;(tt i, ur tttoir employees,makes an* waffanty. cstptcwor implied, of o-'iSumcs anylif.it Ibbllllr "I topuiniblMly far die accuracy, cominformation,apparatus,|)tfi(cne» ii» usefulness of anypfoducl or proem disclosed, olrepresents that its usenuuld nut Infflnjc prtvalcly owm

CONTENTS1. Introduction 1A. Program History 18. Small-Diameter Horizontal Subterren.e System 412. System Description 5III. Suaeiary ef System Specifications 9IV. Description of LASL-Developec! and CommerciallyAvailable Subcomponents 9A. General 9Q. Description of Components 9V. Development Program 12A. Versatility of Kale-Forming Assembly 12E. Development of Attitude-Control Sensors 13C. Examples of Deviation Sensors 13D. Alignment Control Section (ACS5 15VI. Operations 16VII. Conclusions and Discussion 17APPENDIXAnalysis of Proposed Alignment Control Scheme 2011

A VERSATILE P-OCK~MELTING SYSTEM FOR THE FORMATION OFSMALL-DIAMETER HORI2OMTAL GLASS-LIKED HOLESbyD. L. SinsABSTRACTRock-melting penetrators with diameters ranging from SO mm{?. in.) to 76 mm (3 in.) have reached a stage of development atthe Los Alamos Scientific Laboratory (LASL) which suggests thatthese devices are ready for practical application. Prototyperefractory metal penetrators have formed glass-cased verticalholes of 26 m (32 ft) in a single run, and horizontal holes withdiameters up to 127 nsn (5 in.) are expected in the near future.These small horizontal holes can be usted for underground utilityconduits; for high-explosive shot emplacement; and as drainageholes to stabilize road outs or embankments.Design concepts and preliminary specifications are describedfcr a Subterrene system that forms snail-diameter horizontal holesin rock by melting and simultaneously lines the hole with glassyrock melt. Most components of the system are commerciallyavailable. Deviation sensors and alignment-control units car beadded to ensure that the holes are straight. The design andoperation of this Subterrer.e system are described and proposeddevelopment approaches for the hole-fonning assembly are discussed.I. INTRODUCTIONA. Program HistoryRock-melting penetrators (Subterrenes)are under development at the Los AlamosScientific Laboratory (LASL) to produce selfsupportingglass-lined holes in rock andsoil (Fig. 1) by progressive melting ratherthan by chipping, abrading, or spoiling.Rocks and soils melt at temperatures thatare relatively high: coimon igneous rocksat t< 1500 K, almost at the melting temperatureof steel {1500 to 1800 K). Thus, themelting penetritors must utilize refractorymetals such as molybdenum (Mo) and tungsten(W), which melt at 2880 and 3650 K, respectively,and which, in addition, have lowcreep rates at the rock-melting temperatures.

Excavation by rock- and soil-meltingoffers potentially new and novel solutionsto the three major areas of the excavationprocess:• Making the hole or breaking up therock.• Providing structural support forthe bore hole.• Removing or displacing the debrisor cuttings.The liquid form of the rock- and soil-meltproduced by a heated penetrator introducesnew solution concepts into the latter twoareas:• The liquid melt can be formed intoa glass lining to seal or supportthe walls of the bore hole, and• Any excess liquid melt can be chilledand formed into glass rods, glasspellets, or rock wool (Figs. 2 and3); or used to form a glass-casedcore that can be removed by presentwire-line methods.The liquid melt produced by soil- androck-melting techniques offers the potentialof a complete systems approach to the processesof hole making, tunneling, and excavation.The LASL development program inrock- and soil-melting techniques has alreadydemonstrated in laboratory and fieldtests an attractive advancement in practicalexcavation technology for the production ofshort, horizontal, small-diameter holes.This experience has been partially developedthrough the extensive testing of meltingconsolidatingpenetrators (MCPs). The testsconsisted of:• Melting 50-mm (2-in.)-diam, glasslineddrain holes in Indian ruins 3at Bandelier National Monument (Fig. 4).• Melting a 50-mm (2-in.)-diam glasslinedvertical hole in Los Alamosvcicanic tuff to a depth of 26i\.(82 ft) in a single run.• Melting a 50-mm (2-in.)-diam glasslinedhorizontal hole in Los Alamosvolcanic tuff to a length of 16 m(50 ft) (Figs. 5 and 6).• Melting a sequence of 76-mm (3-in.)-diam glass-lined holes in volcanictui T f in the laboratory (Fig. 7) .Fig. 2. Hole melted in granite specimen with an extruding penetrator. Note debris.

Fig. 3.Rock-wool and black glass debrisfrom holes melted by extrudingpenetrator.Fig. 5.Consolidating Subterrene Penetrator"holing through" a 16-m (50-ft)-long horizontal hole.Fig. 4.Modular Subterrene field demonstrationunit melting drain holesat Bandelier National Monument.Fig. 6.Stem aitd service head in positionto melt a 50-mm (2-in.)-diamhorizontal hole.

additional field tests and for demonstrationsof improved consolidating and extruding penetrators.In addition, LASL is currently developinga 114-mm (4.5-in.)-diam, consolidating,coring penetrator that will produce a 63-ron(2.5-in.)-diam glass-encased core.B. Small-Diameter Horizontal SubterreneSystemThe coring capability for the Subterrene,together with the commercial needs for hori-V 8zontal holes for underground power lines 'and a review of reguests for information onthe rock-melting Subterrene, has promptedthe preparation of preliminary design conceptsand specifications for a horizontalSubterrene capable of melting glass-lined,76-mm (3-in.)-diam holes to lengths of *>> 50 m(165 ft) with sufficient accuracy for mostcommercial applications. Horizontal glasslinedholes cf this diameter and lengthcould be useful as:Fig. 7.Consolidating penetrator aftermelting a 76-mm (3-in.)-diamhole in £os Alamos tuff.• Melting stable, 50-mm-diam glass-casedholes in shales, adobe, and alluvium(Pig. 8).In addition, the prototype test program hasdeveloped a universal extruding penetrator(UEP) designed for hard, dense rock. Testswith this unit have:• Melted 66-mm (2.5-in.)-diam holes inbasalt and granite (Fig. 2).• Demonstrated the capability oftailoring debris for differentapplications to meet varying debrisreturnsystems (Fig. 3).A modularized, mobile field-test anddemonstration unit (Fig. 4) has been constructed,and was used successfully formelting glass-lined drainage holes in thefloor of Indian ruins at Bandelier NationalMonument. This test rig will be used for• Glass-lined drain holes for subsidedmines.« Glass-lined drain holes through dikedareas to accelerate drainage afterflooding.• Injection holes for burning mines.• Sealed, glass-lined inspection holesin mine faces or in dax. abutments.• Sealed, glass-lined inspection holesin suspected pollution areas.• Underground utility conduits fortelephone, gas, water, and televisionlines.• Glass-lined holes for high-explosiveshot emplacement.• Drainage holes to stabilize roadcuts and embankments.System descriptions, preliminary designconcepts, and detail component descriptionsare presented in the followingsections, along with indications of additionaldevelopment programs required toprovide subsystems that are not yet availablefor this versatile horizontal holemeltingdevice. Such a device will also

AFig. 8.External surface of glass-lined hole melted in dry alluvium.provide necessary and valuable informationfor the development of the Geoprospector*system-II.SYSTEM DESCRIPTIONThe components of the proposed smalldiameterhorizontal Subterrene system, depictedin Pig. 9, are similar to those of themodularized rock-melting Subterrene demonstrationunit shown in Fig. 4. These componentsinclude:« ft stem advancer. Fig. 10, that willcontinuously advance the stem by use of twoindependent hydraulic cylinders and remotelyoperated stem clamps.• A dual-tube stem consisting of aflush outer steel tube, coupled in sections,and an insulated inner copper tube. Thesetubes provide the electric-power conductorsSea Ref. 7, p. 19,for a brief descriptionof this continuously coring tunnelprospecting device.to the heated penetrator, circulate coolantto the hole-forming assembly (HFA), and providea force path to transfer the thrust tothe advancing melting penetrator.• Circulating, compressed-air coolant,to cool the stem, chill the glass-hole lining,and form small glass pellets (or rockwool) from the excess melt produced by a UEP.This excess melt debris is carried to thesurface and ducted through the service headinto a separating and collecting station.The return coolant from a consolidating penetratoris ducted directly into the ambientair.• A quick-disconnect service head,Fig. 11, that connects the operational linesto the stem (i.e., electric power for thepenetrator, coolant air for glass-formingand debris removal, and sensor and instrumentationleads).• The HFA (hole-forming assembly).Figs. 12 and 13 , which is selected to fitthe job requirement, can be assembled interchangeablyfrom the following subcomponents:

Fig. 9.Horizontal Subterrene melting awater aervice hole.electricalGroundRwartCiteStm ClompStandard DualTube Stem8 DebrisFig. 11. Quick-disconnect service head.HjdrouBeCyHndvHydraulicCywxtarPig. 10.Small-diameter horizontal Subterrenestem advancer.- A heated penetrator, to mplt rock orsoil: A melting consolidating penetrator(MCP), Fig. 14, is used in loose soils, alluvium,and low-density rock, and forms aglass lining; whereas a universal extrudingpenetrator (UEP) , Fig. 15, is used in denseor hard rock and produces rock debris.- A glass former, attached directly tothe penetrator, chills and forms the glasshole lining from the liquid melt. For theextruding penetrator, this unit also containsthe components to chill the extrudateand to process the excess melt into removabledebris.- A centrali2er,to hold the HFA on course.- An alignment control section (ACS). toreturn the HFA to course when deviation isdetected. The controlling force is orientedand applied from the surface control console.- A deviation sensor (PS) or deviationindicator (PI), detects deviation of theHFA from the projected center line of thehole. Signals from the DS or DI are processedand displayed on the control console.The HFA can be made up in a variety of

(o;-Penetrator ^-Glass Former Stem-,—Centralizerim h=£ Deviation Indicator—(c)fe=== =1-StemDeviation Sensoror Indica'or- -Al'gnment Control Sensor Cable-Fig. 12. Hole-forming assemblies: (a) simplest HFA-penetrator, glass former, andstem; (b) addition of centralizer; (c) additional deviation indicator;(d) complete assembly with alignment control.He Purge Flow—Penstrxiror (Contolklating) Electrical Thrust.StemPyrographiteInsulatorGraphiteElectrode^-Pinetratcr [Eftlruding)Fig. 13. System schematic for a horizontalconsolidating and horizontalextruding Subterrene showing therequired functions of the components.Electric CurrentFlow PathPOCO GraphiteReceptorFig. 14. Consolidating penetrator forloose soil and low-density rock.

Coolant —IDebris Removal ZoneThrust LoadDebrisExtrudateThin GlassLiningITPyrolyticGraphiteInsulatorExtrusionZoneHeatedPenetratorBodyDense Rock''—Melting ZoneFig. 15. Extruding penetrator for dense rock.configurations, as indicated in Fig. 12, toachieve the needed straightness for a givenjob.• A complement of service units areneeded to furnish electric power to the penetratora, sensors, and instrumentation;coolant air to the stem and glass-former;and hydraulic power to the stem advancerand stem clamps (Fig. 16). The coolant-airsupply also powers an air-oil intensifierfor emergency stem advance and retraction.• A single control and instrumentationconsole will be provided for the necessaryelectric power, hydraulic and air controls,and for displays. Sensor displays andalignment-correction indications will alsobe shown on the console so that one operatorcan supervise the malting of a straight hole.Note that the proposed horizontal rockmeltingexcavation system which forms theglass-lined holes in place can be assembledSrom various subcomponents to produce holesof varying straightness. For example, thehole-forming assembly can:Fig. 16.Oil to CylindersOil ReturnOil to ClampsAirHydraulic and air-control circuitsfor operation of horizontal stemadvancer.• Melt an accessible, glass-lined holeunder obstructions or structures such asroads, highways, railroads, and canals wherehole straightness is not a major factor.This can be accomplished with a simple HFAconsisting of only a penetrator, glass former,and stem, as indicated in Fig. 12(a).• Melt a very straight, accessible,glass-lined hole from an established pointto intersect a target point with a maximumterminal deviation of two hole diameters orless. This will require a HFA equippedwith a deviation sensor, a surface-operatedalignment-control unit, and a sensor signalthat can be displayed on and monitored fromthe control console by the operator[Fig. 12(d)].The proposed system concepts, components,and specifications are detailed in thefollowing sections.

III.SUMMARY OF SYSTEM SPECIFICATIONThe following list summarizes the preliminaryspecifications for a horizontalhole-melting Subterrene system:• Inside diameter of the glass linedhole, 76 ram (3 in.)•Hole-length capability.Rate of penetration,50 nt (164 ft).- For a melt-consolidating penetrator(MCP) in loose alluvial soil up to0.84 nm/s (2 in./min).- For a universal extruding penetrator(OEP) up to 0.42 nnn/s (1 in./rain).The two penetrator types are interchangeable,are electrically powered,and use circulating air for coolingand debris removal.The glass formers and hole sizers areintegral parts of the penetrators.The maximum hole deviation is lessthan two diameters, but the systemcan be assembled in a simple versionfor less accurate operation.Deviation of the HFA from the projectedhole center line is detected by thedeviation sensor, and the amount ofdeviation is displayed on the controlconsole.Directional control of the HFA is providedby a differential cooling systemwhose operation is regulated at thecontrol console for high accuracy.Lesser straightness will be controlledby simple stem rotation.The hydraulic stem advancer-retractoris capable of continuous motion andis provided with remotely operatedstem clamps. Hole alignment can beset within the range of +. 0.25 rad(.15 deg) from the horizontal.The advancing stem will be a dualtube to transmit power and coolantand for debris removal when required.The stGiii will be flush externallyand of sectioned lengths for ease ofhandling.Melting power is estimated at 15 kW,and total available power should bei> 25 kW.A quick-disconnect service headis included.The single control console willincorporate controls for air supply,hydraulic and electrical power; HFAdeviation and amount of applieddirectional control; and instrumentationdisplays.The service units to be includedare:- Air compressor.- Alternating-current generator,engine-driven.- Alternating current-to-directcurrent converter.- Hydraulic pump, motor-driven.- Air-oil hydraulic booster.- Light truck for mobility.Service leads and hoses are suppliedas required.IV.A. GeneralDESCRIPTION OF LASL-DEVELOPEDAND COMMERCIALLY AVAILABLESUBCOMPONENTSThis section describes components ofthe system that are either already developedor can be designed and assembled in a straightforwardmanner from commercially availableproducts.The demonstration rig for 50-ima(2-in.)-diam penetrators has had excellentresults in initial runs.Much of this simple,inexpensive modular rig (Fig. 4), canbe used as the design base for the 76-mm(3-in.)-diam horizontal Subterrene.Othercomponents have been thoroughly tested bothin the laboratory and in field-test rigs.The alignment accuracy of the demonstrationrig is sufficient for many anticipated usesof horizontal, glass=lined holes.In fact,by intermittently rotating the stem and theHFA of 50-ront (2-in.)-diam Subterrenes whilemelting vertical (Fig. 17) and horizontal(Fig. 18) holes, bores were produced thatwere straight to considerably better thantwo hole diameters in 16 m of hole length.B. Description of ComponentsSpecifically, the proposed small-diameterhorizontal Subterrene system would consistof the components detailed below.1. Stem AdvancerThe stem advancer (Fig. 10) willadvance the stem continuously with two independent,twin hydraulic-cylinder units andremotely operated stem clamps.

TT:Fig. 17.Photograph showing degree ofstraightness in a glass-linedvertical hole.Fig. 18.Photograph showing degree ofstraightness in a glass-linedhorizontal hole.• Normal operating pressure will bo6.S MPa (1000 psi) for an advancing loadper cylinder pair of 20000 >J (4550 lb f ) anda retracting pull of 28000 H (6350 lb f ).• Emergency operation will use fourcylinders with a maKimuro of 13.8 MPa(2000 psi).• The frame (head and base of eachcylinder pair) will be adapted for fasteningto anchor posts, and will be rigid atthe above loads.• Retraction time of a cylinder pair,with normal operating pressure using thehydraulic pump only, will be 20 t 5 s.2. Advancing Stem• The dual-tube advancing stem (Figs.11 and 12) will be similar to that used onthe modularized, mobile rock-melting Subterrenedemonstration unit.• The stem will be flush externallyand slightly smaller in diameter than theHFA. The inner copper tube will have aninside diameter of i> 27.5 mm (1 ^ in.).• The operating temperatures of thestem are estimated to be less than 600 K.Materials used in stem construction near theHFA will have an operating life of 3000 h atthis temperature. Additional stem sectionswill be constructed of conventional materials(low-carbon steel) and will operate at lowertemperatures (4CO K).• The stem will be assembled in lengthsof 1.5 m (5 ft) and 3 m (10 ft).3. Service HeadThe service head (Fig. 11) will providea quick disconnect (and connect) ofthe surface supply lines to the stem (electricpower, coolant, instrumentation, anddebris removal).4. Hole-Forming Assembly (HFA)The hole-forming assembly (Fig. 12)for the simplified small-diameter horizontalSubterrene system would be assembled fromthe following.• A heated penetrator will be selectedfor the anticipated rock or soil to be10

encountered. Melting-consolidating penetratore76 mm (3 in.) in diameter (Fig. 14)will be used for melting glass-lined holesin alluvium and low-density rock, and willbe similar in design to the consolidatingpenetrators that have been developed. Universalextruding penetrators, which axe interchangeablewith melting-consolidatingpenetrators in the HFA, are used for meltingin dense or hard rock. The design and constructionof this type penetrator is alsowell advanced. Both penetrators will produce

and accuracy are required, a deviation sensor(DS) and an alignment-control section(ACS) will have to be added to the HFA. Developmentof these units is discussed in thenext section.V. DEVELOPMENT PROGRAMA. Versatility of Hole-Forming AssemblyThe subsystems (see Section III) ofthe small-diameter horizontal Subterrenesystem are, with three exceptions, eitheralready in use or are commercially available.The three exceptions are:• A deviation indicator,• A deviation sensor,• An alignment-control section.The deviation indicators and deviationsensor subsystems can be adapted from availableinstrumentation and electronics, butthe alignment-control unit will require adevelopment program and is unique to theproposed horizontal hole-forming system.. These additional subsystems allow aplanned programming of hole-forming assemblies(HFAs) for jobs requiring varying levelsof hole straightness and completionaccuracy. Desired levels of performancecan be achieved by assembling HFAs in thefollowing configurations:Assembly A. A heated consolidating orextruding penetrator (depending on geologyand density of the formation) is used withan advancing stem [Fig. 12(a)] to melt,e.g., horizontal, shallow surface drainholes; equipment-placement holes; and utilityconduits having moderate tolerances forinstallation misalignment. The course ofthe melted hole is controlled by periodicpartial rotation of the advancing stem toequalize deviations caused by eccentricityof the assembly.Assembly B. A heated penetrator, centralizer,and advancing stem [Fig. 12(b)Ican be used to extend the length of holesmelted with alignment requirements similarto those of Assembly A.The centralizerholds the heated penetrator on course, allowinghigher stem loads, increased penetrationrates, and longer controlled penetration.Periodic partial rotation is againused to equalize deviations due to assemblyeccentricity.The centralizer assists inthe control of penetrators over longer andmore accurate runs such as utility conduitsfor high-voltage supply and gravity-sewerconnectors.Assembly C.This system consists of aheated penetrator, centralizer, deviationindicator , operator signals, and advancingstem [Pig. 12{c)l.In addition to providingthe increased hole-alignment capability ofAssembly B, the operator is alerted wheneverthe HPA deviates by a preset amountthe proposed hole center line.fromBy indicatingto the operator the quadrant of deviation(viewed down the hole) thu operator may initiatea course correction by quadrant rotationof the advancing stem rather than byperiodic partial stem rotation.Continuedquadrant deviation would signal a mechanicalcause, either a change in geologic formation(boulders) or stem deformations.Assembly D. A heated penetrator, deviationsensor (or deviation indicator), alignment-controlsection, centralizer, operatorsignals, and advancing stem [Fig. 12(d)]are assembled.This unit can track the deviationof the HFA assembly from the projectedcenter line of the hole in terms ofazimuth and bearing, and display this informationon the control console.The alignment-controlsection allows the operatorto turn the HFA toward the projected holecenter line.This assembly also allows theoperator to follow and to control the HFAin a predetermined deviated path.Such positivecontrol of the hole-forming assemblywill increase the capacity of the smalldiameterhorizontal Subterrene system forThe deviation indicator is used for quadrantdeviation signal and control.12

following critical paths or intersectingsmall targets.B. Development of Attitude-Control SensorsSeveral approaches to the developmentof sensors, deviation indicators, and alignment-controlsystems are being investigated.The deviation indicator (01) shown conceptuallyin Fig. 19will flash a light onthe control console to alert tbe operatorthat the hole-forming assembly has deviateda predetermined amount in a given quadrant(viewed from the stem-advancer end).Thesignal is generated when the cantileveredsection of the inner tube is contacted bythe outer housing after a predetermined deflection.This approach is similar to thatof a simple torque—trench indicator.The development of a deviation sensor(DS) can choose among several possibilities:• Laser optical systems are currentlyin use for aligning tunnel-boring machines;however, although the HFA will probably deviatemore than one diameter in a guidancecontrolcycle and although the use of alaser is therefore questionable, these systemswill be reviewed for possible adaptationof the HFA.• Inertial guidance systems are widelyused for navigation and attitude-controlsystems.These systems will also be reviewed.• Gyrostabilizers are extensivelyused for navigation, attitude control, and9-11bore-hole surveying.They will be reviewedfor possible applicati n for inclusionin the HFA.A preliminary review indicatesthat hole size and length of timeto melt a hole may restrict their use toattitude and directional control.• Surface triangulation of a seismicsource in the HFA may be a method to determinehole deviation.Results to datehave not been promising, but a state-of-theartreview should reveal whether sufficientprogress has been made to accurately trackan HFA.• Triaxial dc magnetometers are inuse for attitude-sensing and navigation.In one current application the deviceis following the path of a directionaldrilling tool and signals any deviationsof a bore hole in conventional oil, gas,and water drilling, or in guiding thedrilling of life-support holes to trappedminers. A review of this system will determineits adaptability for HFA use.C. Examples of Deviation SensorsTwo possibilities discussed above areused to illustrate the sensor section ofthe HFA, the surface display, and the operator'suse of the display to initiatecorrective action (see Figs. 19, 20, and 21)An open-loop sensing and control system isconsidered adequate for the length of holespecified in Section III.The relatively simple deviation indicatorshown in Fig. 19 can alert theoperator if the HFA is deviating in a givenquadrant. A section of the inner tube isbuilt as an independent cantilever beam byusing a flexible bellows connection. Fourcontacts are placed around the inner tubewith a small initial standoff clearancefrom the tube. Deflection of the outerhousing, forced by hole deviation, willcause contact between the inner tube andone of the four contacts. Closing of thecontact will light up a corresponding signalon the control console. Correctiveaction can then be initiated either by rotatingthe advancing stem to equalize mechanicalalignment, or by using an alignment-controlsection in the HFA. Physicalorientation of the advancing stem is maintainedby aligning and clamping fiducialprotractors that are attached to the stemsection at the stem advancer.A triaxial magnetometer sensor candetect rotation of its axes relative to aninitial ori'entation. Figure 20 showsschematically the use of a triaxial magnetometeras the deviation sensor for a13

Signal IndicatorConsole insert -Insulating Spider to Firmly HoldInner Tuba in Outer Hauling7 J \High Resistance Segmented4 Contacts-' ^ H Signal { PickupCantilevar Sectionof Inner TubeCoolantReturnOrienting Clamp LocatedBehind Advancing Stem ClampTo Align Signal Pickup ToStarling Referance-Deflected OuterHousingPig.19. HPA deviation indicator.PositionOisplay--ProjectedHole CenterSensorTrloxialMagnetometer—\Signal ToDisplay—'SSSSSS/SSSSA.OuterHousingInner Tube—' Standard Stem -SectionFig.20. Triaxial magnetometer deviation sensor.

small-diameter horizontal Subterrene. Thepower to the sensor and the return signalsis carried in a multiple-channel cable toa signal processor. After processing, thechange in position of the HFA is displayedon an oscilloscope screen in the controlconsole. A computer can be used to plotcontinuously the excursions of the HFA fromthe hole center. However, penetration ratesare sufficiently slow to determine HFA excursionsby hand-calculation (Fig. 21),eliminating computers and plotters.D. Alignment Control Section (ACS)One method of applying a realigningturning force to a heated penetrator whilemelting a hole is to selectively cool oneriiesnjHs. I 0 L ft1 10 202JLJ30509040UP10Hand CdaAMon02S•9TcisIL20ui Pamr/stion in mitfiN10KFig. 21. HFA deviation plot board.aide of the outer housing of a section ofthe hole-forcing assembly (HFA). This canbe accomplished by diverting the inlet-coolantflow as shown in Fig. 22. A gravityactivated.-oolant-channeling valve, rotationallyaligned with the stem, makes it p° s ~sible to select the aziniuthal location o£the cooled side on the advancing housing andthus to apply directive force to the HFA fromthe control console. Construction and operationof such a device are outlined inFig. 22. The gravity-activated coolantchannelingvalve is an eccentrically weighteddisk that is free to rotate on frictionlessball bearings within the cuter tube of thealignment-control section. Thus, if thestem is rotated at the sten advancer end,the coolant-channeling valve retains itsrelevant position with respect to the meltedhole. In addition to a passage for the innercoolant- (and debris-) return tube, thecoolant-channeling valve has two ports: one,labeled A in Fig. 22, is for total coolantbypass when no corrective force is required.The second passage, B, is used toselectively channel the coolant flow intoCoolant Passage C to provide an azimuthallychilled portion of the outer tube. Thiscooler region will tend to cause a deflectionof the tube,which, in turn, will generate amoment to act on the penetrator (see Appendix)Immediately downstream of the coolantchannelingvalve is a bulkhead with fiveports. Port A is for normal flow bypass andis spaced between Ports E and D, two of theCoolant Passage BrCoolD-'A-'E-'A- yNormal Coolant Paitogt AEccentric Mass -Worm Clais LiningCoolant Channallng Vein-I. Fig. 22. Alignment control section.Coolant Rolurn -and Debris15

four ports (D, E, F, and 6) spaced 90 degapart for selective flow control. Thesefour ports are led through the outer housingso that all four connect with Coolant PassageC. Coolant Passage C extends along oneside of the outer housing for a distancesufficient to produce the required turningforce when coolant is ducted through.For normal flow bypass, the stem is rotateduntil Port A in the coolant-channelingvalve is in line with Port A in the bulkheadwith Coolant Passage C facing up. Thisposition is narked at the stein-advancer endwith a fiducial protractor clamp placed onthe advancing stem. When deviation of theheated penetrator from the center line ofthe hole is detected and shown on the surfacedisplay (Fig. 20), the operator canmake the necessary correction. For example,if the display shows left deviation, theoperator rotates the stem 90 deg to theright, so that the coolant passage, C, ismoved to the right-hand side of the hole andPort B is aligned with Port 6 in the bulkhead;Pert A is blanked off. Differentialcooling of the outer housing will turn theHFA back toward the hole center line, atwhich time the coolant is returned to normalbypass flow by returning the stem-positionindicator at the advancer to the Passage-Cup position.Other systems of alignment control canbe visualized, such as having three or fourequally spaced coolant passages and adjustingthe coolant flow in the HFA with remotelycontrolled valves. The smallness of a 76-mmdiamhole and the restricted volume availablefor HFA control suggested the conceptof a gravity-activated coolant-channelingvalve for alignment control.VI.OPERATIONSThe components listed and described inSections III and IV will be selected or designedto be modular and interchangeable.The HFA can be assembled in any of thefollowing configurations:• Consolidating penetrator with stescentraliz rs.• Consolidating penetrator withdeviation indicator and stemcentralizers.• Consolidating penetrator withdeviation indicator, stem centralizers,and alignment-control section (ACS).• Extruding penetrator with any ofthe above options.The correct HFA will be selected tofit the individual job requirements, includingthe desired accuracy in the locationof the melted hole. When maximumaccuracy is desired, the center line of thehole can be established by conventionalmethods, e.g., by usual land-surveying asindicated in Fig. 23.The stem advancer and support equipmentare then moved to the starting pointof the hole. The HFA (and a section ofstem) are clamped in the stem-grippingclamps. A transit and stadia rods are usedto check alignment of the bearing and theinclination angle determined by the survey.Adjustments are made by blocking and edgingthe stem-advancer base. The support equipmentis located as the terrain permits,with the control console close to the stemadvancer. All equipment is started, operated,anri serviced according to the manufactr'ijr'sinstructions. Service lines areattached, and melting of the hole is started.Stem-gripping clamps on the pairs ofadvancing hydraulic cylinders are used alternately:While one clamp is advancing,the other is retracting in preparation fora continuous advancing stroke. All functionsrelated to advancing and retractingthe stem and the HFA are controlled fromthe console., with the exception of addir-j(or removing) additional stem sections.When additional stem is required, theoperator:• Seduces power and coolant flow tozero.16

Survfyor't Tronlf-OitfngSFl-• Continues the two previous stepsuntil HFA is out of hole.• Secures all equipment.If required, the hole can then be surveyedby visual observation or instrumentation toevaluate straightness, glass-casing thickness,etc.VII.CONCLDSIONS AND DISCUSSIONFig. 23. Establishing the hole center line.• Stops advancing pressure and releasesthe rear stem-advancing clamp,returning this clamp to the full-outposition.o Releases bladder pressure in quickdisconnectservice head (QDSH).• Slips off QDSH and unplugs signalleads.• Adds stem section and tightensconnection after plugging-in signalleads.• Slips on QDSH, replugs signal leadsto console and repressures bladder.• Raises power and coolant flow toprevious values.• Regrips stem and applies previousload.The stem is retracted (when the holeis finished or for any other reason) withthe following steps; the operator:• Reduces stem load to zero.• Reduces power to zero.• Reverses thrust load to retract mode.• Maintains coolant flow until thestem pulls freely (stem drag only).• Shuts off retraction force.• Reduces coolant flow to zero andremoves QDSH.• Pulls out stem until the next stemconnection is accessible. Loosensand unscrews connection.• Unplugs signal leads and racks stemsection.The development of small-diameter Subterrenerock-melting penetrators has reachedthe stage where the design of a 75-mm (3-in.)-diam system for forming horizontal, glasslinedholes is possible. Contacts withutility companies and requests for informationfrom industrial firms have indicatedthe need for such a device.A comprehensive development programwould have to address two major areas:• The development of an alignmentcontrolsubsystem.• The conduct of an economic studyand a market survey.A most attractive feature of horizontalhole-melting Subterrene systems is the capabilityof varying the accuracy of holestraightness to match job requirements.This is achieved by including or omittingthe appropriate sections in the hole-formingassembly.The information and experience gainedfrom the development and commercializationof the horizontal hole-melting system willbe of value to other Subterrene system developments.The benefit derived can be anticipatedto be:• Field data on service life andreliability of components, particularlypenetrators.• Extension of the technology to themelting of holes with curved paths.• Experience that will lead to horizontalhole-melting systems withincreased diameter and range.• Adaptation of the perfected alignment-controlscheme to verticalhole-melting systems.17

The successful development of thehorizontal, small-diameter melting systemcan contribute significantly to further developmentsin subsequent S^.bterrene programs.This influence is shown schematicallyin Fig. 24. In addition to valuable experienceand direct data on service lifeand reliability obtained in commercial applications,the effort will help in forminga scientific and engineering basis for designand optimisation of subsequent devices.The very small-diameter melting penetrators;see Fig. 25 for an early prototype) cani.'ind uses such as punching holes in concreteor masonry walls, but difficult miniaturizationproblems will need to be solved iflong holes are to be made. In addition,the experience with 75-mm-diam units willcontribute to the development of a Geo-14prospector, illustrated in Fig. 26, andwill offer early inputs to the solutions ofposition sensors and guidance problems.Sralt Dfc-eurSyltc^sDirect ZGTTJITCMfippl(fatten* forlitill!, Lines, e-.c.Cortrj tn ur-tcfisollfls*P.3 0«nie ForraticnsGecprospcctorFig.24. Effect of 75-mm-diam horizontalSubterrene system on subsequentresearch and development.TUBULAR FLEXSTEMFig. 25. Early prototype of 10-mm-diamrock-melting subterrene.POSITION SENSORGLASSCOOLANT aPOWERCORE REMOVALTUBEPACKERDRIVERMELTERFig. 26.Coring .Geoprospector with position sensor and directionalguidance systems capability.18

REFERENCES1. E. S. Robinson, R. M. Potter, B. B. Mclnteer, J. C. Rowley, D. E. Armstrong,R. L. Mills, M. C. Smith, Editor, "A Preliminary Study of the NuclearSubterrene", Los Alamos Scientific Laboratory report LA-4547 (April 1972).2. J. W. Neudecker, "Design Description of Melting-Consolidating PrototypeSubterrene Penetrators," Los Alamos Scientific Laboratory report LA-5212-MS(February 1973).3. R. E. Williams and J. E. Griggs, "Use of the Rock-Melting Subterrene forFormation of Drainage Holes in Archeological Sites," Los Alamos ScientificLaboratory report LA-5370-MS (August 1973).4. R. G. Gido, "Description of Field Tests for Rock-Melting Penetration,"Los Alamos Scientific Laboratory report LA-5213-MS (February 1973).5. J. W. Neudecker, A. J. Giger and D. E. Armstrong, "Design and Developmentof Prototype Universal Extruding Subterrene Penetrators," Los AlamosScientific Laboratory report LA-5205-MS (March 1973).6. R. E. Williams, "Development of a Modularized Mobile Rock-MeltingSubterrene Demonstration Unit," Los Alamos Scientific Laboratory reportLA-5209-MS (March 1973).7. D. L. Sims, "Identification of Potential Applications for Rock-MeltingSubterrenes," Los Alamos Scientific Laboratory ueport LA-5206-MS(February 1973).8. James Paone, "Horizontal Holes for Underground Power Lines," Proc.Tunnel and Shaft Conf., Minneapolis, MN, May 15-17, 1968, pp 93-113.9. R. L. Waters, The Electro-Mechanics Company, P. 0. Box 1546, Austin, TX,letter communications, April 1973.10. Sperry-Sun Well Surveying Catalogue 723, "Magnetic Steering Tool", p. 4049.Sperry-Sun Well Surveying Co., P. 0. Box 36363, Houston, TX 7703611. Humphrey, Inc. Bulletin FG-1270, "Surveyor Bore Hole Directional Systems",Humphrey, Inc., 2605 Canon St., San Diego, CA 9210612. C. Ishan, Scientific Drilling Control, 4040 Campus Drive, Newport Beach,CA, personal communication, April 1973.13. L. A. Rubin, "New Survey Systems for Drilling," Telcom, Inc., McLean, VA1971.14. J. W. Neudecker, "Conceptual Design of a Coring Subterrene Geoprospector",Los Alamos Scientific Laboratory report in preparation.19

APPENDIXANALYSIS OF PROPOSED ALIGNMENT CONTROL SCHEMEThe parameters affecting the design and Therefore, if the length, L, of the ACS unitpath are .1 6.0 x 10" 6 x 10 80.008 m -1 This moment is of sufficient magnitude to^ SS mill -induce the required path deviation whilep 0.075generating only low stresses in the holeformingperformance of the alignment control section(ACS) proposed in the main body of the reportis 1.0 m, the derivation at the end of theunit will be given bycan be derived by reference to Fig.A-l. The temperature difference establishedA == 0.0033 m = 3.3 mm.across the diameter of the ASC by the divertedcoolant will induce a curvature inthe housing given byIf the ASC is initially rigidly fixed by acentralizer section at one end and the penetrator1 _ a ATP ~T~'(A-l) at the other end. Fig. A-Kb), itwill exert a moment given byif the unit is free to deflect [Fig. A-l(a)],M =E I(A-2)fPwhere AT = effective temperature difference; wherei) = radius of curvatureE = elastic modulus of the materialfrom which the ACS is constructedc. - mean coefficient of thermalexpansionI = area moment of the ACS crossD = diameter of the housing.section.Taking E = 207.0 GPa (30 x 10Typical values for the projected design andlb f /in. 2 ),the data above»and combining Egs. (A-l) andmaterials are:o = 6.0 x 10" 6 , K" 1(A-2), the moment (M) and induced stress (a)are:D = 75 mm = 0.075 mM = 2.6 x 10 3 N-m (2.27 x 10 in. lb f )AT = 100 K.The curvature and radius of the deflecteda = 62 MPa (9.000 lb f /in. 2 ).125 m.assembly.Penetralor-- Glass FormerAlignment Control - ...Section I— BenIflna MomentM j MEE:306(110)ReactionV -Devlotlon S«nsoror Indicotor(b)20Fig. A-l.Proposed alignment control scheme.