Laserfiche WebLink
~'~ i <br />999 <br />1~ttleApplegate,lnc. <br />Consultants for Land, Mineral and Water Development <br />April l 1, 1997 <br />Mr. Rick Mills <br />Twentymile Coal Company <br />29515 Routt County Road #27 <br />Oak Creek, CO 80467 <br />RECEIVED <br />APR 11 ~~7 <br />Dhrlrbn of Mlnitplfi !k 5#96~e~Y <br />RE: Tw~entynrile Coal Mine; Permit #C-82-056; Map 25 and Map 31 Revisions for Colorado <br />Division of Minerals and Geology (DMG) <br />Dear Rick: <br />We aze happy to report we have completed the updates for the referenced maps. The purpose of <br />the update was to address two azeas of concern. The first was required reclamation grading and <br />related bond amounts associated with Map 31. 7'he second was to provide information on <br />conveyance of upstream drainage through the updated Map 31 grading/disturbance area. Please <br />allow us to offer the following brief summaries of our findings on these issues. <br />We have attached a Map 31 Revision plan showing updated proposed reclamation grading for the <br />subject area. This revised grading plan provides for minimal disturbance and earthmoving. The <br />DMG staff request to address slope drainage required review and revision to the proposed <br />reclamation grading. <br />Key design criteria included minimum disturbance, minimum haul distances, balanced cut and <br />fill, maximum 3 foot horizontal to 1 foot vertical (3:1) slopes, 2% minimum overland slopes, and <br />1% minimum gradient for an incidental local collector swale. The resulting earthwork for these <br />reclaimed grades will require 300,000 cubic yazds of cut and the same amount of fill. <br />It should be noted the existing buildings will be placed in the existing high wall azeas and <br />crushed, taking up some of the fill volume. The existing buildings and equipment are estimated <br />to occupy 88,000 cubic yards. Assuming a 90% reduction in volume for crushing, this will <br />reduce the fill volume required by 8,800 cubic yards to 291,200 cubic yards. <br />For convenience, and at DMG staff request, existing building locations have been shown for plan <br />and cross-section orientation. The buildings aze to be removed as per permit conditions and will <br />not remain in the final reclaimed land use. In addition, the Map 31 Revision plan has been <br />developed utilizing ]0 foot contours at the request of DMG staff. This contour interval provides <br />more detail than the 25 foot interval utilized in the previously approved Map 31. <br />11990 Grant Street, Suite 555 • Denver, Colorado 80233 • (303) 452-6611 • Fax (303) 452-2759 <br />