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Drainaye calculations and Typical Sections are shown on the <br />_ "Mine Plan". <br />4. CONVENERS <br />The site plan includes the installation of a conveyers For <br />handling of coal from the mine to yard stockpiles. Coal from the <br />stockpiles is loaded with a front end loader into semi trailers <br />for transport. to the designated mar4;et. <br />A. Undeiyround Belt Line: A '+P inch underground r_aGle <br />suspended pelt line has been installed to convey coal from <br />tl-ie mine. The drive unit and head pulley is located at the <br />entrance of the center entry. <br />B_ Stacking Conveyer :_ A 36 inch stacking conveyer from the <br />main underground belt line is used to stockpile coal in the <br />yard for loading and shipping to market. <br />5. PONDS, IMPOUNDMENTS AND DIVERSIONS (See 2.06.10 for Twin Pines <br />Coal Sales <br />The site plan for Twin Pines No. 2 Mine has been develooed to <br />work within the constraints of the e>:istin^ mined area and to <br />provide maximum protection of the downstream drainage areas. <br />Run-off volumes, peak dis.charaes, and other hydrological <br />calculations were derived from the United States Soil <br />Conservation Service Manual, "Procedures for Determining Peak <br />Flows in Colorado" dated March 1980. Subsequent to submission of <br />the Permit Application, the hydrology of the mine site was <br />modeled usir~y the Soil Conservation Service Computer Program, TR- <br />20. Several scenario's have been presented for Permit Renewals <br />and subsequent reviews. <br />Ir. brief, the existing mine site had no provisions for reducing <br />run-off across spoil hanks and other disturbed areas, with <br />exception of depressions left in the spoil. Thus, during periods <br />of heavy run-off, the down stream drainage was subjected to <br />increased sediment loads and the spoil banks and existing roads <br />continued to erode. Very little vegetation had evolved to protect <br />the existing slopes. The site plan, as developed, includes <br />controlled drainage of the mine site with run-off diverted to <br />sedimentation ponds with sequential seeding and mulching of fill <br />slopes to prevent erosion. Where possible all run-off from <br />disturbed areas has been directed to sedimentation ponds. Run-off <br />from the down slopes of the North Spoil Area Dike, Spoil Area <br />Access Road, and Lewis Gulch Fill Slopes does not flow to a <br />sedimentation pond. These slopes were seeded and mulched with <br />construction of the mine site to alleviate erosion and <br />sedimentation. <br />Drainage from the mine site has been divided into two areas for <br />control due to site restrictions which. limit th,e physical size of <br />• detention ponds. A brief description of the two areas is as <br />follows: <br />REVISED 6/19/93 <br />73 <br />