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<br />iii iiiiiiiiiiiu iii <br />STATE OF COLORADO <br />Roy Romer, Governor <br />DEPARTMENT OF NATURAL RESOURCES <br />MINED LAND RECLAMATION DIVISION <br />DAVID C. SHELTON, Director <br />DATE: July 30, 1987 <br />T0: Grassy Gap File - C-81-039 <br />FROM: Candy Thompson ~~ <br />RE: PIT N0. 1 SEDIh1ENT POND REMOVAL DEMONSTRATION <br />I reviewed the calculations submitted by the operator for sediment pond <br />removal at the Pit No. 1 area. The vegetative sampling at the pit and <br />calculations have been compared to the requirements of Rule 4.05.2(2). The <br />compliance requirements are discussed point by point below in regards to the <br />Pit No. 1 area. <br />1. Vegetative success: In June of 1987 the operator sampled vegetation at <br />Pit No. 1 according to ML RD requirements. The vegetation cover was 56%. <br />From the permit application the pre-mining cover for the mountain shrub <br />community was 31.1%. The herbaceous cover for Pit No. 1 is greater than <br />90% of the original. <br />Comparison of soil loss from reclaimed vs. undisturbed site: The <br />operator utilized the Universal Soil Loss Equation to compare the <br />disturbed and undisturbed condition. No soil sampling for erodability <br />was done. However, the figure used for the disturbed condition is <br />conservative. The soil loss predicted off both conditions was 0.23 <br />tons/acre/year. Therefore, the disturbed land is contributing no more <br />sediment than the undisturbed site. <br />3. Receiving Stream Standards: There are no springs evident to date off the <br />Pit No. 1 area. Also, no appreciable spring development is predicted. <br />THerefore, receiving stream standards for chemical constituents will be <br />in compliance. There are no applicable standards for suspended sediment <br />for the receiving streams. <br />Based upon compliance with the above factors the Division approves <br />removal of the Pit No. 1 sediment pond. <br />/vjr <br />1480E <br />423 Centennial Building, 1373 Sherman Street Denver, Colorado 80203-2273 Tel. (303) 866-3567 <br />