Handbook for Methane Control in Mining - AMMSA

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Exploration drillholes can be a major conduit for gas migration. Typically, these will be drilledduring the initial phases of opening up an ore body or new sections of the same ore body. 18 In atleast one case in the United States, decades-old deep wells that had not been plugged properlymay have provided a link between coal measures and permeable strata, which in turn funneledthe gas into a major fault system. Gas subsequently entered the mine via water carried along asecondary fault that had branched off from the major fault zone.Gas testing. Another primary task when opening up a new mine or expanding an existing mineis testing for methane gas at all stages in the exploration and development of the mine. Gas testsmust be conducted at the collar of exploration drillholes 19 and at the roof of newly exposed faces.If no gas is found during those two stages, it is less likely to be present in the production phase ofthe mine’s life. However, gas at just one drillhole or at one newly exposed face indicates apotentially larger gas problem. Immediate measures must be taken to confirm the presence ofmethane by laboratory analysis and to carefully sample all of the other drillholes and newlyexposed faces that are part of the project. 20Methane can sometimes be associated with water in underground mines. Any gas bubbling fromwater coming from a fault zone or from pools of water collecting in the floor of the mine or tunnelshould be sampled and analyzed for methane and other gases, such as carbon dioxide andhydrogen sulfide.For mines where the presence of methane is not definitely established, Thimons et al. [1979]established a simple guideline that would enable mine personnel to evaluate the methane hazard.In their research, they measured trace methane concentrations in 53 metal/nonmetal mines, findingthat mines with a return concentration exceeding 70 ppm of methane were inevitably classifiedas gassy. 21 Although a measurement of concentration alone is not the complete methanestory, a return concentration exceeding 70 ppm should serve as an alert to the presence of gasthat has not yet shown itself in other ways.16318 In the Republic of South Africa, there has been considerable study of the occurrence of methane gas associatedwith gold mining in the Witwatersrand. The Chamber of Mines published a comprehensive text on mitigating gasproblems entitled Flammable Gas in Metal Mines: A Guide to Managers to Assist in Combating Flammable Gas inMetal Mines [Association of Mine Managers 1989]. This guide contains specific sections on methane occurrenceand detection, the prevention of flammable gas accumulations, ventilation systems, mining methods, equipmentmodifications, “hot work” permits, and the responsibilities of mine officials with regard to methane control.19 For more on sampling from boreholes, see Chapter 2.20 In addition to methane, laboratory analysis should test for other gases that may be flammable or toxic, such asethane or hydrogen sulfide.21 In 1979, the MSHA classification system for metal/nonmetal mines with methane was different from the currentstandard. However, the triggers that lead to extra precautions (such as measurement of 0.25% or an ignition in themine) are similar.
164REFERENCESAndrews JN [1987]. Noble gases in groundwaters from crystalline rocks. In: Saline water andgases in crystalline rocks. St. John’s, Newfoundland, Canada: Geological Association ofCanada, Special Paper 33, pp. 234–244.Association of Mine Managers [1989]. Flammable gas in metal mines: a guide to managers toassist in combating flammable gas in metal mines. Johannesburg, Republic of South Africa:Chamber of Mines of South Africa, Safety and Technical Services.CFR. Code of federal regulations. Washington DC: U.S. Government Printing Office, Office ofthe Federal Register.Cook AP [1998]. The occurrence, emission, and ignition of combustible strata gases in Witwatersrandgold mines and Bushveld platinum mines, and means of ameliorating related ignitionand explosion hazards. Final project report, project GAP 504. Braamfontein, Republic of SouthAfrica, Safety in Mines Research Advisory Committee (SIMRAC) (www.simrac.co.za).Edwards JS, Durucan S [1991]. The origins of methane. Min Sci Technol 12(2):193–204.Eschenburg HMW [1980]. Sources and control of methane in gold mines. J Mine Vent SocS Afr, August.Fritz P, Frape S K, Miles M [1987]. Methane in the crystalline rocks of the Canadian shield.In: Saline water and gases in crystalline rocks. St. John’s, Newfoundland, Canada: GeologicalAssociation of Canada, Special Paper 33, pp. 211–223.Grau RH, Marshall TE, Finfinger GL [1988]. Evaluation of methane liberations from productionblasts in domal salt mines. In: Proceedings of the Fourth International Mine Ventilation Congress(Brisbane, Queensland, Australia, July 3–6, 1988). Carlton, Victoria, Australia: AustralasianInstitute of Mining and Metallurgy.Iannacchione AT, Grau RH III, Sainato A, Kohler TM, Schatzel SJ [1984]. Assessment ofmethane hazards in an anomalous zone of a Gulf Coast salt dome. Pittsburgh, PA: U.S. Departmentof the Interior, U.S. Bureau of Mines, RI 8861. NTIS No. PB84214162.Jackson KAB [1957]. Methane on St. Helena Gold Mined Limited. Association of Mine Managersof South Africa.Lumsden AM, Talbot R [1983]. Develop data for review of metal and nonmetal mine methanehazard classification. Golder Associates, Inc. U.S. Bureau of Mines contract No. J010060.NTIS No. PB83258624.Molinda GM [1988]. Investigation of methane occurrence and outbursts in the Cote Blanchedomal salt mine, Louisiana. Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines,RI 9186. NTIS No. PB90270083.
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TMIC 9486Information Circular/2006H
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ORDERING INFORMATIONCopies of Natio
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ILLUSTRATIONS—ContinuedPage4-6. U
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HANDBOOK FOR METHANE CONTROL IN MIN
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4Below 5%, called the lower explosi
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6reduced pressure, except at very l
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8Static electricity. Protection aga
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10Figure 1-4.—Estimated methane c
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12LAYERING OF METHANE AT THE MINE R
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14good eyesight. 24methane level.Ot
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16a material balance indicated that
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18As an example, assume that themet
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20Figure 1-10.—Relative frequency
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22Davies AW, Isaac AK, Cook PM [200
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24Margerson SNA, Robinson H, Wilkin
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CHAPTER 2.—SAMPLING FOR METHANE I
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29USING PORTABLE METHANE DETECTORST
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Out-of-range gas concentrations in
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Figure 2-3.—Recorder chart from a
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35Industrial Scientific Corp. [2004
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38peaks, not the overallmethane lev
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40hung on J-hook assemblies, which
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42Methane dilution effectiveness.Th
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44found that effective scrubber ope
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46When the scrubber exhaust is not
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48Methane monitors are usually moun
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50to use radial bits instead of con
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52Mott ML, Chuhta EJ [1991]. Face v
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54Service, Centers for Disease Cont
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56Methane accumulationsaround thesh
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58corner and by 43% at supportNo. 4
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60When using water sprays to reduce
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62Cecala AB, Zimmer JA, Thimons ED
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64DESIGNING BLEEDER SYSTEMSAs part
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66Caved area characteristics. The c
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68then move this gas into the activ
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70perform tests to determine whethe
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72A major purpose of the bleeder sy
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74• Inlets to the pillared area n
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76REFERENCESCFR. Code of federal re
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78Methane is released into each min
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80Figure 6-1.—Gas content of coal
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82Figure 6-3.—Simplified illustra
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842. In-mine inclined or vertical b
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861. Packed cavity method and its v
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88Table 6-3.—Methane capture rati
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90Early experiences with this metho
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9211. At the surface installation (
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94• Estimated cost for moderately
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96Thakur PC [1981]. Methane control
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98Anomalous, unanticipated methane
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100Vertical methane drainage boreho
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102Figure 7-2 shows a mine entry ap
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104obvious solution to this problem
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106Figure 7-8.—Hypothetical gas c
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108Lama and Bodziony [1998] compile
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110In-mine methane drainage systems
Page 117 and 118: 112Iannacchione AT, Ulery JP, Hyman
Page 119 and 120: 114More sophisticated reservoir eng
Page 121 and 122: 116coal lithotype on gas content is
Page 123 and 124: 118FORECASTING REMAINING GAS-IN-PLA
Page 125 and 126: 120⎛ y⎞⎜⎛⎞ ⎛ ⎞= ⎜
Page 127 and 128: 122emissions. The geometry and size
Page 129 and 130: 124Reservoir models require a subst
Page 131 and 132: 126King GR, Ertekin T [1989a]. A su
Page 133 and 134: 128an area of 314 ft 2 would requir
Page 135 and 136: 130In the case of the abovementione
Page 137 and 138: 132FILLING SHAFTS AT CLOSED MINESFi
Page 139 and 140: 134Hinderfeld G [1995]. Ventilation
Page 141 and 142: 136To calculate the effectiveinert,
Page 143 and 144: 138exhaust. The remaining diesel ex
Page 145 and 146: 140required only 4 min. As a result
Page 147 and 148: 142Figure 11-1.—Desorption test a
Page 149 and 150: 144enclosed in a tunnel-like struct
Page 151 and 152: 146Kolada RJ [1985]. Investigation
Page 153 and 154: 148air in a 6-ft by 9-ft by 6.5-ft
Page 155 and 156: 150represents flammable mixtures. F
Page 157 and 158: 152• In Eastern Europe, petroleum
Page 159 and 160: 154Category II applies to domal sal
Page 161 and 162: 1562. Monitoring for gas and taking
Page 163 and 164: 158These mines typically have large
Page 165 and 166: 160Dave Graham is the safety and he
Page 167: 162Figure 13-2.—Examples of metha
Page 171 and 172: 166APPENDIX A.—ONTARIO OCCUPATION
Page 174 and 175: 169CHAPTER 14.—PREVENTING METHANE
Page 176 and 177: Ways to confirm the presence of gas
Page 178 and 179: 173The tunnel face is usually venti
Page 180 and 181: 175Figure 14-5.—TBM ventilation s
Page 182 and 183: face. While one of these elements a
Page 184 and 185: 179ELIMINATING IGNITION SOURCESElec
Page 186 and 187: 181INDEXAAbnormally gassy faces....
Page 188 and 189: 183NNatural ventilation, coal silos
Page 190 and 191: Delivering on the Nation’s Promis
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