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U.S. Department of Energy
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Geotechnical study of auger mining of coal pillars

Journal Article · · Miner. Matters; (United States)
OSTI ID:5955088
In recent years, the US Department of Energy and the US Bureau of Mines have been developing underground augering machines to be used for coal pillar extraction in retreat mining. Now a bidirectional auger machine has been designed, fabricated, and tested at a mine in Illinois. Evaluation of underground augering concepts indicates that the bidirectional auger has economic potential for pillar extraction in mines only where (1) poor roof conditions would preclude the use of continuous miners and (2) constraints on allowable surface subsidence require long-term stability of roof/pillar/floor structure. Geotechnical studies are being conducted to evaluate the stability of auger holes, coal ribs between auger holes, remaining coal pillars, and expected surface subsidence due to auger mining. The geotechnical study has three components: field studies, laboratory studies, and analytical studies. Some of the results of these studies are: (1) most of the failures due to augering at this southern Illinois mine are expected to be in the floor; (2) rib pillars between auger holes are expected to be stable with relatively little rib rashing; (3) the remaining pillar after augering of coal pillars should be stable with a considerable margin of safety; and (4) the expected standup time for intersections after augering (based on the Geomechanics Classification Rating) varies between 1000 to 15,000 hours. 1 figure. (DP)
OSTI ID:
5955088
Journal Information:
Miner. Matters; (United States), Journal Name: Miner. Matters; (United States) Vol. 5:1; ISSN MIMAE
Country of Publication:
United States
Language:
English