Handbook for Methane Control in Mining - AMMSA

More documents

Recommendations

Info

34For this reason, when operators are encountering methane, they should calibrate for methane.On the other hand, if higher hydrocarbons are being encountered, operators should calibrate witha higher hydrocarbon, such as pentane or propane.Calibration-sampling correction value tables for avariety of combustible gases are readily available[Industrial Scientific Corp. 2004]. More informationon the response of catalytic sensors to differentgases is available from Firth et al. [1973].MISINTERPRETING WARNING SIGNSIt is not unusual to misinterpret a gas warning sign, especially in underground workings thoughtto have no gas. A primary reason is that the gas flow varies with the excavation rate. Suppose,for example, a tunnel-boring machine (TBM) begins to cut into an area of gassy ground, releasingmethane into the ventilation air. The machine-mounted monitor on the TBM senses this gasand shuts it down. After spending some time tracking down the source of the shutdown andfiguring out what to do, a worker begins to hunt for gas with a handheld detector. The workerhunting for gas cannot find much because the emission dropped when the TBM stopped. Thus,everyone concludes that the monitor on the TBM is not working properly. Given two instruments,one with bad news and the other with good news, the tendency is to believe the goodnews. However, when methane detection and monitoring instruments fail, they rarely give afalse alarm or a false high reading; in other words, they rarely indicate gas when there is none.The usual failure mode is to not register gas that is present. Therefore, when any instrumentregisters gas, it is better to trust the reading and take appropriate precautions.Operators must be especially cautious when successive methane readings vary more than theynormally do. When the airflow is low or when measurements are taken close to the source, themethane will not be well mixed into the air. This could lead to a high reading in one area with alow reading just a few feet away. This incomplete mixing can indicate that the ventilation air isdeficient and that even higher concentrations of gas might be found nearby.REFERENCESCFR. Code of federal regulations. Washington, DC: U.S. Government Printing Office, Office ofthe Federal Register.CSA [1984]. Combustible gas detection instruments. Section 5.3.1, CSA standard C22.2No. 152–M1984 (product ID 2001201). Mississauga, Ontario: Canadian Standards Association.Firth JG, Jones A, Jones TA [1973]. The principles of the detection of flammable atmospheresby catalytic devices. Combust Flame 20:303–311.
35Industrial Scientific Corp. [2004]. Gas detection made easy. P/N 1600–0029. Oakdale, PA:Industrial Scientific Corp.Kim AG [1973]. The composition of coalbed gas. Pittsburgh, PA: U.S. Department of theInterior, Bureau of Mines, RI 7762. NTIS No. PB221574.Kissell FN, Banfield JL, Dalzell RW, Zabetakis MG [1974]. Peak methane concentrationsduring coal mining: an analysis. Pittsburgh, PA: U.S. Department of the Interior, Bureau ofMines, RI 7885. NTIS No. PB233424.Mills B [2003]. Fatal shaft explosion report investigation, McElroy Coal Co., McElroy mine,Permit No. U–83–33, Central Cambria Drilling Co., contractor No. C–618, January 22, 2003.Fairmont, WV: West Virginia Office of Miner’s Health, Safety and Training.Raine EJ [1960]. Layering of firedamp in longwall working. Trans Inst Min Eng (U.K.)119(10):579–597.Taylor CD, Chilton JE, Mal T [2002]. Evaluating performance characteristics of machinemountedmethane monitors by measuring response time. In: De Souza E, ed. Proceedings of theNorth American/Ninth U.S. Mine Ventilation Symposium (Kingston, Ontario, Canada). Lisse,Netherlands: Balkema, pp. 315–321.Taylor CD, Chilton JE, Zimmer JA [2004]. Use of a test box to measure response times formachine-mounted monitors. In: Ganguli R, Bandopadhyay S, eds. Mine ventilation: Proceedingsof the 10th U.S./North American Mine Ventilation Symposium (Anchorage, AK, May 16–19, 2004). Leiden, Netherlands: Balkema, pp. 177–182.Vinson RP, Thimons ED, Kissell FN [1978]. Methane accumulations in coal mine roof cavities.Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, RI 8267. NTIS No.PB277919.Wallhagen RE [1977]. Development of optimized diffuser and spray fan systems for coal mineface ventilation. Waltham, MA: Foster-Miller Associates, Inc. U.S. Bureau of Mines contractNo. H0230023. NTIS No. PB277987/AS.
Page 1 and 2: TMIC 9486Information Circular/2006H
Page 3 and 4: ORDERING INFORMATIONCopies of Natio
Page 5 and 6: ILLUSTRATIONS—ContinuedPage4-6. U
Page 8: HANDBOOK FOR METHANE CONTROL IN MIN
Page 11 and 12: 4Below 5%, called the lower explosi
Page 13 and 14: 6reduced pressure, except at very l
Page 15 and 16: 8Static electricity. Protection aga
Page 17 and 18: 10Figure 1-4.—Estimated methane c
Page 19 and 20: 12LAYERING OF METHANE AT THE MINE R
Page 21 and 22: 14good eyesight. 24methane level.Ot
Page 23 and 24: 16a material balance indicated that
Page 25 and 26: 18As an example, assume that themet
Page 27 and 28: 20Figure 1-10.—Relative frequency
Page 29 and 30: 22Davies AW, Isaac AK, Cook PM [200
Page 31 and 32: 24Margerson SNA, Robinson H, Wilkin
Page 33 and 34: CHAPTER 2.—SAMPLING FOR METHANE I
Page 35 and 36: 29USING PORTABLE METHANE DETECTORST
Page 37 and 38: Out-of-range gas concentrations in
Page 39: Figure 2-3.—Recorder chart from a
Page 43 and 44: 38peaks, not the overallmethane lev
Page 45 and 46: 40hung on J-hook assemblies, which
Page 47 and 48: 42Methane dilution effectiveness.Th
Page 49 and 50: 44found that effective scrubber ope
Page 51 and 52: 46When the scrubber exhaust is not
Page 53 and 54: 48Methane monitors are usually moun
Page 55 and 56: 50to use radial bits instead of con
Page 57 and 58: 52Mott ML, Chuhta EJ [1991]. Face v
Page 59 and 60: 54Service, Centers for Disease Cont
Page 61 and 62: 56Methane accumulationsaround thesh
Page 63 and 64: 58corner and by 43% at supportNo. 4
Page 65 and 66: 60When using water sprays to reduce
Page 67 and 68: 62Cecala AB, Zimmer JA, Thimons ED
Page 69 and 70: 64DESIGNING BLEEDER SYSTEMSAs part
Page 71 and 72: 66Caved area characteristics. The c
Page 73 and 74: 68then move this gas into the activ
Page 75 and 76: 70perform tests to determine whethe
Page 77 and 78: 72A major purpose of the bleeder sy
Page 79 and 80: 74• Inlets to the pillared area n
Page 81 and 82: 76REFERENCESCFR. Code of federal re
Page 83 and 84: 78Methane is released into each min
Page 85 and 86: 80Figure 6-1.—Gas content of coal
Page 87 and 88: 82Figure 6-3.—Simplified illustra
Page 89 and 90: 842. In-mine inclined or vertical b
Page 91 and 92:
861. Packed cavity method and its v
Page 93 and 94:
88Table 6-3.—Methane capture rati
Page 95 and 96:
90Early experiences with this metho
Page 97 and 98:
9211. At the surface installation (
Page 99 and 100:
94• Estimated cost for moderately
Page 101 and 102:
96Thakur PC [1981]. Methane control
Page 103 and 104:
98Anomalous, unanticipated methane
Page 105 and 106:
100Vertical methane drainage boreho
Page 107 and 108:
102Figure 7-2 shows a mine entry ap
Page 109 and 110:
104obvious solution to this problem
Page 111 and 112:
106Figure 7-8.—Hypothetical gas c
Page 113 and 114:
108Lama and Bodziony [1998] compile
Page 115 and 116:
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 and 168:
162Figure 13-2.—Examples of metha
Page 169 and 170:
164REFERENCESAndrews JN [1987]. Nob
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
show all

Handbook for Methane Control in Mining - AMMSA

Create successful ePaper yourself

Delete template?

Save as template?