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_ III IIIIIIIIIIIIIIII <br />999 <br />_ _ _ STATE OF COLORADO _ <br />MINED LAND RECLAMATION DIVISION oF.~o~ <br />Department of Natural Resources ~~~~~~~y9 <br />1313 Sherman Sf.. Room 215 ~`~o <br />Denver, CO 80203 . ~ ; 1 ~ ~ . <br />C ~/ <br />303 866-3567 ~ ~ ie s ~ ~ <br />FA%:303 632-8106 <br />Roy Romer, <br />Governor <br />Fretl R. Banta. <br />DATE: February 12, 1990 ' Orvis~on o:reaor <br />T0: John T. Doerfer, Reclamation Specialist <br />FROM: Daniel I. Hernandez, Reclamation Specialist~~~ <br />RE: Notes on Review of Snyder Ouarry Access Road Sediment Basin Design, <br />Castle Concrete Company, Permit No. M-77-210 <br />Dear John: <br />I have briefly reviewed the design proposals for the Snyder Ouarry Access Road <br />sediment basins submitted to the Division on January 31, 1990, Some notes I <br />had on the proposals are as follows: <br />1, On page 2, the operator states that a certain area of the quarry <br />that drains out onto the access road will be reoraded to drain back <br />into the quarry to reduce the sediment outflow into the proposed <br />sediment basins. The operator then states that the quarry floor <br />will be moved down another 80'-100' from its present elevation. A <br />concern I had with this was that if the sediment basins are to be <br />left as permanent structures and the quarry floor will be <br />daylighted to drain down the road, then shouldn't these proposed <br />basins be designed to capture the sediment flow from the entire <br />quarry area and not just the small drainage basin indicated in <br />Exhibit A? <br />2. Assuming the quarry access road will be lowered during reclamation <br />to the final quarry floor elevation to allow draining of the quarry <br />to occur, will the sediment basins still be functional when the <br />floor is lowered, or will they end up at a higher elevation than <br />the quarry floor and become non-functional? <br />3. On page 3, the operator states that the same slope config~~rations <br />of 2:1 for dry slopes and 3:1 for wet slopes recommended by the <br />operator's consulting aeotechnical firm for the access road <br />shoulders will be adhered to for the sediment basin side slopes. <br />However, the operator goes on to say that if "rock is encountered <br />in the excavation, the slopes can be steeper - theoretically <br />vertical. The majority of the area where the sediment basins will <br />be constructed will be excavation into native material, w~ich is <br />known to be rock." <br />It appears, therefore, that the operator is suggesting that the <br />pond side slopes will be constructed with slopes steeper than <br />