141:
increases, and the result is a chain reaction of pillar failures. Once started, such chain reactions can be extremely difficult to stop, even if they spread slowly. To prevent this from happening, the mine is divided up into areas or panels. Pillars known as barrier pillars separate the panels. The barrier pillars are significantly larger than the "panel" pillars and are sized to allow them to support a significant part of the panel and prevent progressive collapse of the mine in the event of failure of the panel pillars.
200:
125:
116:
keep the size and shape of rooms and pillars consistent, but some mines strayed from this formula due to lack of planning and deposit characteristics. Mine layout includes the size of rooms and pillars in the mines, but also includes factors like the number and type of entries, roof height, ventilation, and cut sequence.
180:(MSHA), pillar recovery mining has been historically responsible for 25% of American coal mining deaths caused by failures of the roof or walls, even though it represents only 10% of the coal mining industry. Retreat mining cannot be used in areas where subsidence is not acceptable, reducing profitability.
172:
is often the final stage of room and pillar mining. Once a deposit has been exhausted using this method, the pillars that were left behind initially are removed, or "pulled", retreating back towards the mine's entrance. After the pillars are removed, the roof (or back) is allowed to collapse behind
149:
Traditionally, the act of mining consists of three steps. First, the deposit is "undercut", where a slot is cut as deep as possible along the bottom of a section of ore. This undercut allows for a manageable pile of rock in later stages. The second step is the drilling and blasting of the section.
115:
Next, mine layout should be determined, as factors like ventilation, electrical power, and haulage of the ore must be considered in cost analysis. Due to the non-homogeneous nature of mineral deposits typically mined by room and pillar, mine layout must be mapped very carefully. It is desirable to
111:
Planning for the development of room and pillar mines operates in much the same way as other mining methods, and begins with establishing ownership of the mine. Following this, the geology of the mine must be analysed, as this will determine factors like the lifespan of the mine, the production
50:
compared to other underground mining techniques. It is also advantageous because it can be mechanized, and is relatively simple. However, because significant portions of ore may have to be left behind, recovery and profits can be low. Room and pillar mining was one of the earliest methods used,
140:
Random mine layout makes ventilation planning difficult, and if the pillars are too small, there is the risk of pillar failure. In coal mines, pillar failures are known as squeezes because the roof squeezes down, crushing the pillars. Once one pillar fails, the weight on the adjacent pillars
150:
This creates a pile of ore that is loaded and hauled out of the mine—the final step of the mining process. More modern room and pillar mines use a more "continuous" method, that uses machinery to simultaneously grind off rock and move it to the surface.
294:
Abandoned mines have a tendency to collapse. In remote areas, collapses can be dangerous to wildlife, but subsidence of abandoned mines can be hazardous to infrastructure above and nearby. Significant amount of coal is left on the pillars as roof support.
136:
require the regular pattern to be modified. The size of the pillars is determined by calculation. The load-bearing capacity of the material above and below the material being mined and the capacity of the mined material determines the pillar size.
261:
Modern room and pillar mines can be few and far between. This is due to many factors, including the dangers to miners associated with subsidence, increasing use of other methods with more mechanization, and the decreasing cost of surface mining.
207:
Room and pillar mining is one of the oldest mining methods. Early room and pillar mines were developed more or less at random, with pillar sizes determined empirically and headings driven in whichever direction was convenient.
270:
Room and pillar mining is not particularly dependent on the depth of the deposit. At particularly deep depths, room and pillar mining can be more cost effective compared to strip mining due to the fact that significantly less
211:
Room and pillar mining was in use throughout Europe as early as the 13th century, and the United States since the late 18th century. It is still in use throughout the US, but has slowed or stopped entirely in parts of Europe.
230:, opened in 1961. This room-and-pillar mine, 620 feet (190 m) below the surface, has square pillars 37 feet (11 m) on a side separating rooms of the same width in a gypsum bed about 10 feet (3.0 m) thick.
42:. Calculating the size, shape, and position of pillars is a complicated procedure, and an area of active research. The technique is usually used for relatively flat-lying deposits, such as those that follow a particular
173:
the mining area. Pillar removal must occur in a very precise order to reduce the risks to workers, owing to the high stresses placed on the remaining pillars by the abutment stresses of the caving ground.
191:
Many room and pillar mines have been abandoned for as long as 100 years. This drastically increases the risk of subsidence unless properly maintained, however, maintenance does not often occur.
380:
HudeÄŤek, V.; Ĺ ancer, J.; ZubĂÄŤek, V.; Golasowski, J. (January 2017). "Experience in the
Adoption of Room & Pillar Mining Method in the Company OKD, a.s., Czech Republic".
283:
Due to a recovery rate as low as 40% in some cases, room and pillar mining cannot compete in terms of profitability with many modern, more mechanized types of mining such as
703:
Singh, Rajendra; Mandal, P.K.; Singh, A.K.; Kumar, Rakesh; Sinha, Amalendu (May 2011). "Coal pillar extraction at deep cover: With special reference to Indian coalfields".
497:
Grgic, Dragan; Homand, Francoise; Hoxha, Dashnor (October 2003). "A short- and long-term rheological model to understand the collapses of iron mines in
Lorraine, France".
218:
Room and pillar mining of gypsum was used in Iowa beginning in 1892, and was phased out of use in 1927 due to low recovery and development of technologies that made
241:, the largest in the world, was opened in 1959. It taps a salt bed 30 metres (98 ft) thick 533 metres (1,749 ft) below the surface, mostly under
215:
Coal mining in the United States has nearly always operated with a room and pillar layout, although originally operated with significantly more manpower.
34:
system in which the mined material is extracted across a horizontal plane, creating horizontal arrays of rooms and pillars. To do this, "rooms" of
342:
Kim, Jong-Gwan; Ali, Mahrous A. M.; Yang, Hyung-Sik (2018-10-27). "Robust Design of Pillar
Arrangement for Safe Room-and-Pillar Mining Method".
425:
Croyle, Floyd D.; Kohler, Jeffrey L.; Bise, Christopher J. (November 1987). "Maximum Demand and Demand
Factors in Underground Coal Mining".
939:
183:
Sometimes retreat mining is not used and the underground space is repurposed as climate controlled storage or office space instead.
161:
are unloaded into mined-out areas, can be used, but are not required. Retreat mining (below) is an example of a process like this.
798:"Subsidence due to abandoned mining in the South Wales coalfield, UK: causes, mechanisms, and environmental risk assessment".
574:"Roadway backfill method to prevent geohazards induced by room and pillar mining: a case study in Changxing coal mine, China"
177:
275:
needs to be removed. This means that today, room and pillar mining is mostly used for high grade, but small, deep deposits.
538:
Paul, Michael, et al. "Mine flooding and water management at underground uranium mines two decades after decommissioning."
878:"Monitoring land subsidence in the southern part of the lower Liaohe plain, China with a multi-track PS-InSAR technique"
641:
309:
780:
682:
932:
837:
1023:
1018:
779:
C. M. Young, Percentage of
Extraction on of Bituminous Coal with Special Reference to Illinois Conditions,
1148:
995:
925:
863:
866:
December 1, 2017; the room and pillar layout is most evident in the mine map shown in
Picture 3 of 17.
850:
523:
665:
132:
Room and pillar mines are developed on a grid basis except where geological features such as
975:
223:
8:
83:
800:
International
Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts
876:
Sun, He; Zhang, Qin; Zhao, Chaoying; Yang, Chengsheng; Sun, Qifa; Chen, Weiran (2017).
75:
510:
899:
815:
811:
720:
647:
637:
595:
472:
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359:
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46:. Room and pillar mining can be advantageous because it reduces the risk of surface
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227:
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are dug out while "pillars" of untouched material are left to support the roof –
245:. The Cargill salt mine 1,700 feet (520 m) below the surface, mostly under
1107:
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314:
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219:
169:
79:
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393:
355:
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903:
849:
Amy Pataki, Richard
Lautens, Salt at the source: a day in a Lake Huron mine,
819:
724:
651:
599:
476:
442:
434:
411:
363:
176:
Retreat mining is a particularly dangerous form of mining. According to the
1044:
1039:
738:
1122:
985:
98:. It has been used worldwide from the Czech Republic to China to the US.
402:
272:
242:
47:
39:
862:
Laura
Johnson, The Cargill salt mine: an other world under Lake Erie,
759:
246:
234:
67:
917:
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199:
158:
91:
63:
1069:
71:
43:
27:
833:
124:
970:
948:
95:
59:
31:
832:
Danny Davis, The Truth about USG, Published in 3 parts in the
666:
379:
222:
more practical, safe, and cost effective. More recently, the
572:
Zhou, Nan; Li, Meng; Zhang, Jixiong; Gao, Rui (2016-11-29).
634:
Modern American coal mining : methods and applications
87:
55:
35:
683:"Room and Pillar Mining: Modern Coal Mining at Its Best"
186:
106:
702:
466:
554:
Guide to underground mining methods and applications
237:
use room and pillar layouts. The Sifto salt mine in
112:
requirements, and the cost to develop and maintain.
836:, Jan. 28-Feb 11, 2010, archived on the web as a
1140:
875:
631:
496:
424:
781:Engineering Experiment Station Bulletin No. 100
571:
469:Mining methods and costs, Iowa Gypsum deposits
933:
54:The room and pillar system is used in mining
680:
51:although with significantly more manpower.
940:
926:
524:Pillar and Roof Span Design in Stone Mines
427:IEEE Transactions on Industry Applications
341:
893:
668:, University of Illinois, September 1915.
589:
578:Natural Hazards and Earth System Sciences
401:
198:
123:
664:S. O. Andros, Coal Mining in Illinois,
344:Geotechnical and Geological Engineering
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551:
128:General Layout of room and pillar mine
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705:International Journal of Coal Geology
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178:Mine Safety and Health Administration
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783:, University of Illinois, page 130.
187:Stage 3—maintenance and remediation
107:Stage 1—exploration and development
16:Horizontal excavation mining method
13:
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606:
560:
370:
14:
1160:
556:. Stockholm, Sweden: Atlas Copco.
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483:
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74:ores, particularly when found as
310:Coal mining in the United States
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843:
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773:
752:
731:
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545:
517:
467:Marshall, Lawrence G. (1959).
203:A Maryland coal mine from 1850
119:
1:
882:Remote Sensing of Environment
511:10.1016/S0266-352X(03)00074-0
320:
265:
256:
812:10.1016/0148-9062(92)94157-m
7:
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10:
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717:10.1016/j.coal.2011.03.003
591:10.5194/nhess-16-2473-2016
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101:
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1011:
1004:
956:
895:10.1016/j.rse.2016.10.037
739:"Springfield Underground"
499:Computers and Geotechnics
394:10.1134/s1062739117011908
382:Journal of Mining Science
356:10.1007/s10706-018-0734-1
153:Other processes, such as
760:"Louisville Underground"
435:10.1109/tia.1987.4505039
429:. IA-23 (6): 1105–1111.
26:is a variant of breast
204:
129:
806:(3): A202. May 1992.
632:Bise, Christopher J.
552:Hamrin, Hans (1986).
540:Proc. IMWA Conference
202:
127:
78:or blanket deposits,
224:United States Gypsum
996:Mountaintop removal
471:. Bureau of Mines.
1149:Underground mining
853:, Fri Aug 15 2014.
681:Sunrise Coal LLC.
226:Sperry mine, near
205:
157:, where discarded
130:
1136:
1135:
1096:
1095:
584:(12): 2473–2484.
239:Goderich, Ontario
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991:Hydraulic mining
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851:The Toronto Star
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711:(2–3): 276–288.
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350:(3): 1931–1942.
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228:Mediapolis, Iowa
24:pillar and stall
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1118:Deep sea mining
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1078:Room and pillar
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305:Longwall mining
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251:Cleveland, Ohio
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20:Room and pillar
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505:(7): 557–570.
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315:Surface mining
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289:surface mining
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220:surface mining
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170:Retreat mining
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165:Retreat mining
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145:Stage 2—mining
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1128:Seabed mining
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388:(1): 99–108.
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279:Disadvantages
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763:. Retrieved
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742:. Retrieved
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687:Sunrise Coal
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403:10084/124488
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1123:Prospecting
1005:Sub-surface
120:Mine layout
1033:Directions
951:techniques
321:References
273:overburden
266:Advantages
257:Modern use
243:Lake Huron
235:salt mines
84:aggregates
48:subsidence
40:overburden
30:. It is a
1113:Automated
1108:Abandoned
1024:Soft rock
1019:Hard rock
971:Quarrying
904:0034-4257
888:: 73–84.
820:0148-9062
725:0166-5162
652:900441678
600:1684-9981
477:680481821
443:0093-9994
412:1062-7391
364:1573-1529
247:Lake Erie
68:limestone
1143:Category
1083:Longwall
1060:Borehole
1055:Bell pit
986:Dredging
966:Open-pit
299:See also
285:longwall
159:tailings
155:backfill
92:soda ash
1088:Retreat
1070:Stoping
1012:Classes
958:Surface
542:. 2013.
195:History
102:Process
72:uranium
44:stratum
28:stoping
981:Placer
949:Mining
902:
818:
765:23 May
744:23 May
723:
650:
640:
598:
475:
441:
410:
362:
134:faults
96:potash
94:, and
70:, and
60:gypsum
32:mining
1101:Other
1050:Shaft
1045:Slope
1040:Drift
976:Strip
526:, CDC
233:Many
80:stone
76:manto
900:ISSN
816:ISSN
767:2019
746:2019
721:ISSN
648:OCLC
638:ISBN
596:ISSN
473:OCLC
439:ISSN
408:ISSN
360:ISSN
326:Note
88:talc
82:and
64:iron
56:coal
890:doi
886:188
808:doi
713:doi
586:doi
507:doi
431:doi
398:hdl
390:doi
352:doi
287:or
249:at
36:ore
22:or
1145::
898:.
884:.
880:.
814:.
804:29
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509::
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445:.
433::
414:.
400::
392::
366:.
354::
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
