25:
222:
regime at the face - high stress on and around the mining face can close up the cleats and pores in the coal seam. This can result in a steep coal seam gas pressure gradient into the seam, (as opposed to a low stress environment where the coal seam gas drains freely into the face area, resulting in a
236:
Outburst management primarily focuses on the prevention of outbursts by pre-draining the gas from coal seams prior to mining. The aim of gas drainage is to lower the gas content of the seam below a certain threshold value, at which time it is considered safe to mine the seam. These threshold values
271:
Mining under "bomb squad" or outburst conditions is no longer considered acceptable, since this method still presents a fatal risk to at least one miner. "Bomb squad" is a special set of operating conditions that used to be adopted when it was anticipated that an outburst could occur. Under "bomb
227:
The statistical results show that the primary factor in coal and gas outbursts is crustal stress (P), followed by sturdiness coefficient (f). The coal seam gas content (W) affect affects coal and gas outbursts as the least important factor.
263:
Induction shotfiring - using a charge (explosive) to test the face and induce an outburst if one is imminent. The explosion would have the effect of fracturing the face and relieving the stress on the face, transferring it deeper into the
214:
of coal - high-strength coal seams appear to be more prone to outbursts. This may be because low-strength coal tends to deform in and around the face area as mining occurs, resulting in stress relaxation (see
149:
Outbursts may range in severity from being barely noticeable, to causing the destruction of an entire mining panel, and throwing pieces of machinery weighing tens of tonnes several metres. An outburst at
279:
Armoured cabins were built on continuous mining machines - these cabins were thought to be able to protect the operator in the event of an outburst. (This was subsequently proven incorrect.)
244:
Gas drainage is achieved by drilling boreholes into the seam in advance of mining. Gas liberated from the seam into the boreholes is transported out of the mine via a pipe range.
199:
Coal seam gas composition - for a given coal seam gas content (in m per tonne), the seam will be much more susceptible to outbursts if the coal seam gas is predominantly
158:, Australia, in June 1985 ejected 350 tonnes of coal and rock and over 3000 cubic metres of gas, killing one miner. An outburst at the nearby South
276:
Minimal manning at the face - particularly during the cutting of coal, only one man at a time was allowed at the face (the continuous miner driver)
174:
Coal seam gas content (measured in m per tonne) - generally, for a given coal seam gas composition, the higher the gas content, the higher the risk
162:
Colliery in 1991 killed three miners. An outburst at
Westcliff Colliery in January 1994 ejected 300 tonnes of coal and rock and killed one miner.
312:
260:- the sequential drilling, blasting, and loading out of the coal face, as opposed to the conventional mechanised method of mining.
241:
being mined. Since the introduction of threshold values, not a single fatality due to an outburst has been recorded in
Australia.
282:
Operators wore full-face masks, connected to a compressed air supply. (This was also found ineffectual in preventing fatalities.)
89:
61:
223:
low seam gas pressure gradient). As mining progresses, this pressure can be violently released, resulting in an outburst.
68:
42:
108:
247:
Where standard gas drainage techniques are ineffectual, mine operators have a number of options. These may include:
75:
46:
320:
193:
57:
344:"Classification of coal seam outburst hazards and evaluation of the importance of influencing factors"
251:
35:
159:
257:
82:
452:
447:
355:
211:
8:
359:
219:
170:
Several factors predispose certain coal seams to being outburst-prone. These include:
373:
420:
363:
151:
178:
155:
141:. Outbursts can be a very serious events, possibly even resulting in fatalities.
425:
408:
200:
182:
441:
377:
238:
134:
390:
368:
343:
138:
292:
409:"Rapid decompression and desorption induced energetic failure in coal"
406:
267:
Not mining that part of the seam - (Lives are worth more than coal.)
24:
186:
203:, as opposed to the case where the coal seam gas is predominantly
204:
196:(the less permeable the coal seam, the more prone to outbursts)
272:
squad" conditions, the following working methods would apply:
126:
130:
393:, Coal Mine Outbursts project, University of Wollongong.
413:
Journal of Rock
Mechanics and Geotechnical Engineering
407:
Shugang Wang; Derek
Elsworth; Jishan Liu (June 2015).
342:
Shi, Xianzhi; Song, Dazhao; Qian, Ziwei (2017-07-06).
49:. Unsourced material may be challenged and removed.
439:
313:"Legislative Assembly Hansard – 12 April 1994"
341:
237:should vary depending on the coal seam and
254:- mining is carried out by remote control.
424:
367:
137:and surrounding strata in an underground
109:Learn how and when to remove this message
165:
144:
440:
231:
125:is the sudden and violent ejection of
177:Geological structures, in particular
47:adding citations to reliable sources
18:
189:(reddish brown powdered coal) zones
13:
400:
14:
464:
433:$ 1. Introduction and background.
23:
391:sample Outburst Management Plan
34:needs additional citations for
384:
335:
305:
16:Violent underground phenomenon
1:
321:Parliament of New South Wales
298:
7:
426:10.1016/j.jrmge.2015.01.004
286:
10:
469:
317:Hansard & House Papers
58:"Outburst" mining
369:10.1515/geo-2017-0024
212:compressive strength
166:Predisposing factors
145:Effects of outbursts
43:improve this article
360:2017OGeo....9...24S
232:Outburst management
119:
118:
111:
93:
460:
430:
428:
394:
388:
382:
381:
371:
348:Open Geosciences
339:
333:
332:
330:
328:
309:
152:Tahmoor Colliery
114:
107:
103:
100:
94:
92:
51:
27:
19:
468:
467:
463:
462:
461:
459:
458:
457:
438:
437:
403:
401:Further reading
398:
397:
389:
385:
340:
336:
326:
324:
323:. 12 April 1994
311:
310:
306:
301:
289:
234:
168:
156:New South Wales
147:
115:
104:
98:
95:
52:
50:
40:
28:
17:
12:
11:
5:
466:
456:
455:
450:
436:
435:
419:(3): 345–350.
402:
399:
396:
395:
383:
354:(1): 295–301.
334:
303:
302:
300:
297:
296:
295:
288:
285:
284:
283:
280:
277:
269:
268:
265:
261:
255:
233:
230:
225:
224:
216:
208:
201:carbon dioxide
197:
190:
175:
167:
164:
146:
143:
117:
116:
31:
29:
22:
15:
9:
6:
4:
3:
2:
465:
454:
451:
449:
446:
445:
443:
434:
427:
422:
418:
414:
410:
405:
404:
392:
387:
379:
375:
370:
365:
361:
357:
353:
349:
345:
338:
322:
318:
314:
308:
304:
294:
291:
290:
281:
278:
275:
274:
273:
266:
262:
259:
256:
253:
252:Remote mining
250:
249:
248:
245:
242:
240:
229:
221:
217:
213:
209:
206:
202:
198:
195:
191:
188:
184:
180:
176:
173:
172:
171:
163:
161:
157:
153:
142:
140:
136:
132:
128:
124:
113:
110:
102:
91:
88:
84:
81:
77:
74:
70:
67:
63:
60: –
59:
55:
54:Find sources:
48:
44:
38:
37:
32:This article
30:
26:
21:
20:
432:
416:
412:
386:
351:
347:
337:
325:. Retrieved
316:
307:
270:
246:
243:
239:coal measure
235:
226:
194:permeability
169:
148:
133:from a coal
129:, rock, and
122:
120:
105:
96:
86:
79:
72:
65:
53:
41:Please help
36:verification
33:
453:Mine safety
448:Coal mining
327:11 December
442:Categories
299:References
293:Rock burst
69:newspapers
378:2391-5447
258:Grunching
139:coal mine
287:See also
187:mylonite
123:outburst
99:May 2009
431:• see:
356:Bibcode
215:below).
205:methane
83:scholar
376:
220:stress
185:, and
179:faults
85:
78:
71:
64:
56:
264:seam.
192:Coal
183:dykes
160:Bulli
154:, in
90:JSTOR
76:books
374:ISSN
329:2018
218:The
210:The
135:face
127:coal
62:news
421:doi
364:doi
131:gas
121:An
45:by
444::
415:.
411:.
372:.
362:.
350:.
346:.
319:.
315:.
181:,
429:.
423::
417:7
380:.
366::
358::
352:9
331:.
207:.
112:)
106:(
101:)
97:(
87:·
80:·
73:·
66:·
39:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.