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1115 <br />H.It 8 provides treatment for the aeoond special condition, ill»s- <br />trtrted schematically in figure B, presented in a few surface ooel minas <br />that are similar in nature to open pit hardrock mining. Such mines <br />arc described in the sppro:imate original contour provtsron as thick <br />seam operations carried out in the same location over a substantial <br />period of time, where such an operation tranaects the coal deposit ver- <br />tically (i.e., the operation moves down through the deposit as it the <br />case to the arts mtatng situation) and where the overburden removed <br />is insulbcient to rcwrn to either the approzimate original configura- <br />tion of elecation. In such cases, the regradWg standard requires that <br />the overburden be used to corer the floor of the mining operation, to <br />provide some drainage control, and to establish a slope of st least the <br />angle of repose agornst the hrghn•alls completely covering the coal <br />seam and ertending to the origins] contour. !ln eagle of repose fill <br />against the highwall procides a surface Rhich may be more stable <br />than the highwall with respect to weather. The covered coal seam is <br />Qrotected in part against accidental combustion, or other problems <br />rf the coal seam is sa aquifer. In addition, the elope of natural tepoee <br />has sn added safety value, since it does not present a hazard to ether <br />wildlife or human life, as would a vertical fsa. <br />These types of operations hold the potential of substantially and <br />permanently disrupting tLe hydrology of an area. A projeMion of <br />reconstruction of surface drarnage from one such operetion is con- <br />tained in a recent IISGS report, "Land and Natural Resoura In- <br />formation and Some Potential Environmental Effects of Surface <br />Mining of Coal in the Gillette area of R'yoming" (GSrcular 743). <br />This projection clearly shows that reestablislrmentof through drsinnge <br />toil] not automatSca]]y occur with this type of mlamation and thus <br />adjustments to site selection may be required. <br />canoe e~tctnavaet, t.axns + ~ ~ 6 <br />Prime agriculture] leads ate those available for grotcing crops <br />Rhich have fire soil quality, wing season, and mwsture supp p <br />needed to produce sustamed hrgh yields econormcally when treated snd <br />managed a,ocording to modern farminngg methods Such lands can be <br />farmed intensively with minimum adverse environmental impacts, <br />]otter energy and eooaomic inputs, and higher yields than noaprime <br />finds. To qualify as prime agncultu~al land, land must meet apecrfic <br />criteria established in 1975 by the Soil Conservation Service (men- <br />tioned above) for moisture supply, water table, Gooding, soil <br />temQetaiure, permeability, acidity, alkalinity, salitti , stonine~, and <br />erasron hazard. The baste mfotaration needed to classify lands as <br />Prime or nonprime lands is contained in soil surveys which are avail- <br />able on over 60 percent of the Nation <br />In 1975, the Soil Conservation Servioa ooaduded a poteatia] ~aP' <br />find study that included a survey of the Aration's prime agncultnra] <br />lends. From that study, it is estimated that the Nation Las 364 trillion <br />acres that meet the cnteria for prime lands and that have sot bees <br />eoarerted permanant]p to other uses Two-hundred and fifty million <br />acres are currerrtl cropped, Dut of the remainder, 88 trillion ate in <br />trillee~~be iprrraated~TLen ia~about 24ami 1 one tastes that oonldbe <br />