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E~~A <br />S coa,compenr Seneca Coal Company <br />March 7, 2007 <br />Mr. Michael Boulay aC CC 11 ` , <br />Colorado Division of Reclatation, Mining and Safety RLCL1 V ~D <br />1313 Sherman Sweet, Room 215 MAR 0 9 2007 <br />Denver, CO 80203 <br />DivMining and Safety n~ <br />Re: Seneca Coal Company <br />-- -I'ostroine Channel Desi~a & Permsit Issues Meeting on March-5, 20tY7- _ - - - - - _ - -- <br />Dear Mx. Boulay: <br />Thank you fox taking time Monday to meet with representatives of Seneca Coal Company (SCC). We <br />believe the discussions were very helpful and significant progress was made toward meeting SCC's intent <br />to utilize turf reinforcement matting ('I'RIvl) material in the design and construction of postmine channels <br />at the Seneca II, Yoast and II-W Mines. However, before we move forward we want to assure that <br />Colorado Division of Reclamation, Mining and Safety (CDRMS) and SCC aze in consensus as to what <br />was discussed and agreed to during our meeting. <br />The issues that were discussed and the agreed direction for SCC to proceed axe as follows: <br />• CDRMS is receptive t.~ use of TR'Qs as a substitute for rock riprap where SCC can demcnstra±e that <br />the design is stable. <br />Design storm runoff values will be estimated based upon a revegetated watershed condition and <br />curve number inputs will be selected from the approved values which aze found in the respective <br />permit application packages. <br />•- . Cbanr_el geometry for TRAI installation will be-based.upon equipment-limitations. Trapezoidal- <br />shaped channels will have bottom widths of either three-feet or 10-feet. Side slopes will be 4H:1 V. <br />• TRM installation will Follow manufacturer's recommendations. Tlie matting edge at the top of a <br />channel will be trenched. Matting margins at the top of channel banks will be covered with soil <br />material to facilitate sheet flow entering the channel over the mat and not undercutting the TRM. <br />• With the technical revision (TR) applications, SCC will provide typical designs for vegetated, rock <br />riprap and TRM channels. Summary tables will be updated as appropriate. The TRbI designs will be <br />generic so that SCC may use more than one TRM product. SCC will include manufacturers <br />specifications in either tabular or text format to Facilitate CDRMS review of the designs. <br />Manufacturer's literature may also be included as reference material. <br />• Seneca Coal Company • P.O. Box 670 • Hayden, Colorado 81639 <br />• Telephone (970) 276-3707 • FAX (970) 276-3014 <br />