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that sufficient quantities of fill material exist on site to complete both portal and mine <br />bench backfilling activities. <br />A single drill hole currently exists at the mine site in Hay Gulch and is used as a water <br />well. The landowner has requested that this well remain open following permanent <br />cessation of operation. The Division previously agreed with this request and hereby <br />reaffirms this previous approval. Therefore, the drill hole is not required to be sealed. <br />(4.07). <br />VI. Use of Explosives <br />The King Coal Mine is an underground mining operation; as such, no surface blasting <br />will occur. National King Coal has a permit (No. 527-Renewal) from the Colorado <br />Division of Mines to store and use explosives for the underground operations. This <br />permit is renewed annually. As all blasting occurs underground, additional requirements <br />of this section are not applicable. (4.08). <br />VII. Coal Mine Waste <br />A. The Division has approved plans for use, construction and maintenance of a coal <br />mine waste disposal area. Derails concerning the construction of the waste pile can <br />be found in appendix 7-(1) of the Permit document. The coal refuse will be mine <br />waste rock extracted over the life of the mine. The material is composed of dense, <br />medium grained sandstone with occasional shale and carbonaceous shale partings. <br />The valley fill waste pile is located east of the mine entrance, beginning just east of <br />the shop building and extending up the east side drainage approximately 900 feet. <br />A limit equilibrium static analyses was performed using effective stresses to assure <br />long term stability of the bank. A relatively flat 2.Sh : lv slope is used for the face <br />of the waste pile. This analysis provided a range of factors of safety between 1.85 <br />and 2.74, well above the required 1.5. An intercept channel was constructed at the <br />top of the bank to divert flow originating above it away from the bank and into the <br />east side drainage. Similarly, a channel was constructed at the bottom of the waste <br />bank to intercept runoff from the pile. An under drain system was constructed <br />beneath fill and drains into the east side drainage (4.04.8(3)). <br />B. The applicant has demonstrated that disposal of such materials will not adversely <br />affect water quality or flow, vegetation, public health, or stability of the disposal <br />area based on hydrologic, geotechnical, physical, and chemical analyses. The waste <br />pile designs exceed the minimum safety factor of 1.5. The new designs for the <br />expanded waste pile were approved February 9, 1998. <br />C. The disposal area will be inspected on a regular basis by a qualified professional <br />specialist under the direction of the professional engineer, experienced in <br />19 <br />