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VI. <br />VII. <br />Use of Explosives <br />The King Coal Mine is an underground mining operation; as such, no surface blasting will <br />occur. National King Coal has a permit (No. 527-Renewal) from the Colorado Division of <br />Mines to store and use explosives for the underground operations. This permit is renewed <br />annually. As all blasting occurs underground, additional requirements of this section are <br />not applicable. (4.08). <br />Coal Mine Waste <br />A. The Division has approved plans for use, construction and maintenance of a coal mine <br />waste disposal azea. Details concerning the construction of the waste pile can be found <br />in appendix 7-(1) ofthe Permit document. The coal refuse will be mine waste rock <br />extracted over the life of the mine. The material is composed of dense, medium <br />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 the <br />shop building and extending up the east side drainage approximately 900 feet. A limit <br />equilibrium static analysis was performed using effective stresses to assure long term <br />stability of the bank. A relatively flat 2.Sh av slope is used for the face of the waste <br />pile. This analysis provided a range of factors of safety between 1.85 and 2.74, well <br />above the required 1.5. An intercept channel was constructed at the top of the bank to <br />divert flow originating above it away from the bank and into the east side drainage. <br />Similazly, a channel was constructed at the bottom of the waste bank to intercept <br />runoff from the pile. An under drain system was constructed beneath fill and drains <br />into the east side drainage (4.04.8(3)). <br />B. The applicant has demonstrated that disposal of such materials will not adversely affect <br />water quality or flow, vegetation, public health, or stability of the disposal area based <br />on hydrologic, geotechnical, physical, and chemical analyses. The waste pile designs <br />exceed the minimum safety factor of 1.5. The new designs for the expanded waste pile <br />were approved February 9, 1998. <br />C. The disposal azea will be inspected on a regulaz basis by a qualified professional <br />specialist under the direction of the professional engineer, experienced in construction <br />of similar earth and waste structures. Inspection by this person has been approved by <br />the Division as appropriate. (4.10.2(1)). <br />18 <br />