Laserfiche WebLink
<br />11. Page 2.04-39 (iv) has deleted the wording "The operator will perform a <br />study of the possibility of inflow associated with faults and fractures <br />by the end of 1992, which is after the first full year of mining in the B <br />seam and will be three to four years before Coal Gulch is undermined." <br />Please reinstate a revised form of this wording that makes it applicable <br />to all drainages to be undermined. <br />12. On page 2.04-38 it states that the location of the Elk Creek No. 1 Spring <br />is noted on the previous page. I cannot locate this description. Please <br />clarify. <br />13. The application did not have a discussion of Spring No. 8. This spring <br />discharges perennially from the old Oliver Mine at a constant rate of <br />12 gpm. Water quality as electrical conductivity is about 3,500 umhos. <br />This spring is just west of the Hawks Nest silos, on the cut embankment, <br />in the ditch along old county road 133. During a June 1991 inspection, <br />A flow of about 30 gpm +~as estimated. The mine plan calls for mining <br />under the abandoned workings, and the water in the Oliver Mine may end up <br />in the Somerset workings. Therefore, the water quality and quantity <br />information is important. <br />A considerable volume of water may be in the abandoned workings of the <br />Oliver Mine. This mine has a mined-out areal extent of 170 acres. The <br />discharge from this mine is occurring at the top of the dip, so it can be <br />assumed that the mine is mostly flooded. Given that this mine was mined <br />using room and pillar method with a 50 percent extraction rate, a mining <br />height of six feet and a flooded area of 90 percent, the mine has a <br />potential flooded volume of 460 acre-feet. <br />(a) The Somerset permit revision application should be updated to <br />include a discussion of this spring. <br />14. The Division is concerned with the possibility of a catastrophic <br />inundation of the Somerset Mine. The Somerset Mine will advance under <br />the flooded working of the Oliver Mine and the potentially flooded Hawks <br />Nest Mine in the D and E seam, respectively. When this occurs, there is <br />the possibility that a fault or drill hole that is in hydrologic <br />communication with the flooded D or seam will flood water into the <br />Somerset Mine at a rate that the mine cannot handle. This scenario has a <br />greater chance of occurring when retreat mining fractures the interburden <br />between the B seam and the flooded Oliver workings in the D seam. During <br />a telephone conversation with Bill Ponceroff of MSHA, he said that MSHA <br />would not approve a mine plan that would retreat mine under flooded <br />workings, but that development mining could be allowed after a thorough <br />review of the mine plan. <br />(a) The Somerset Mine must get prior approval from MSHA before <br />initiating mining under the flooded workings. This approval shall <br />be forwarded to the Division for its review and approval. <br />(b) Include a study of faults, fractures and drill holes that may be <br />encountered that could potentially conduct inflow from the flooded <br />workings of the Oliver and Hawks Nest Mines to the Sanborn Mine. <br />-3- <br />