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in a subsidence choke at heights between 760 and 920 feet . <br /> This height is much less than the average depth of cover , <br /> hence surface subsidence will not occur . (See Appendix IV-F-3 <br /> for further discussion on the subsidence bulking factor) <br /> There are no indications of surface subsidence <br /> in Coal Basin even though there were extensive mining opera- <br /> tions for several years around the turn of the century <br /> and continuously on a much larger scale since 1956 . An <br /> on-site inspection of the most likely area where subsidence <br /> could occur , above Nos . 1 and 2 mines , was conducted on <br /> September 12 , 1980 by two representatives of Willard Owens <br /> Associates , Inc . , Mr . John G . Roscoe, Mining Engineer ; <br /> Ms . Nancy B . Lamm , Project Geologist , with Mr . Douglas <br /> Bowman, Environmental Coordinator for Mid-Continent Resources , <br /> Inc . They could find no evidence that the land area above <br /> these two mines had been affected by subsidence (See Willard <br /> Owens Subsidence Inspection Report at Appendix IV-F-1) . <br /> The very nature of the renewable resources identi- <br /> fied with the land above and within the areas of possible <br /> subsidence lead to the logical conclusion that there would <br /> be no diminution of their reasonably forseeable use even <br /> if worst case subsidence did occur . The limited quantity <br /> of aquifer recharge, if any , from the geologic formations <br /> that lie above the minable coal seams , in comparison to the <br /> very large amounts of water produced by the extensive <br /> Coal Basin and East Muddv watersheds , lead to the logical <br /> conclusion that subsidence would have no effect on the reason- <br /> ably forseeable aquifer recharge function . <br /> 32 <br />