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A single drill hole currently exists a[ the mine site in Hay Gulch and is used as a water <br />• well. The landowner has requested that this well remain open followins 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 requiremen~ <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. Details 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 waste bank is located east of the mine entrance, beginning just east of the shop <br />building and extending up the east side drainage approximately 900 feet. A limit <br />equilibrium static analyses was performed using effective stresses to assure long term <br />stability of the bank. A relatively flat 3h:ly slope is used for the face of the waste <br />pile. This analysis provided a range of factors of safety between 1.85 and2.74, well <br />above the required 1.5. An intercept channel was constructed at the top of the bank <br />to divert flow originating above it away from the bank and into the east side <br />drainage. Similarly, a channel was constructed at the bottom of the waste bank to <br />intercept runoff from the pile. An under drain system was constructed beneath fill <br />and drains into the east side drainage (4.04.8(3)). Coal processing waste will be <br />generated by an airjig processing plant and this waste willalso be placed in the coal <br />waste disposal area (4.10.1 (1)). <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 wash <br />pile designs exceed the minimum safety factor of 1.5. The current design limits of <br />the pile has been reached and new designs for an expanded waste pile will be <br />submitted by September, 1997. <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 />18 <br />