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FF'OC1 6RLRZ 8 R.:,SOC I R~i E= I NC • Mr. Gregg Squue Page 3 February 2l, 2001 FRr M=. ~7E~ X53 '? ~ 30 • Feb. 23 2001 02:33PM P4 • One pit open with no groundwater exposed, RRA is not mined • One pit open with no groundwater exposed, RKA is mined • Une pit mined out and partially filled with groundwater, a second pit is active • Two pits are mined out, one pit is filled with groundwater and the second pit is partially filled with groundwater, the third pit is active • All three pits aze reclaimed and full of groundwater. These scenarios will compazed to the base case to assess potential impacts and what, if any, mitigation will be required. This study will also be used to determine il'additional analysis beyond the initial study area is warranted. Tbis report will be forwarded to DMG, Gazfield County and the City of Rifle when it is completed. Item 6 -Mining depth in the RRA. The depth of mini ~o in the RRA will be related to market demand. LJsing a five (5) feet depth, the estimated amount of in place and recoverable tons i+: Area Tons Phase Acres In Place Recoverable 1 17 222,156 211,048 2 6.53 85,334 81,067 Total 2353 307,490 292116 Assuming a 200,000 ton per yeaz dctnarrd, the majority of the RRA would need to be mined in one yeaz. The costs associated with preparing an area for mining and mobilizing mining equipment require that the maximum amount of material be recovered from a mining area in the shortest time possible. nth these economic factors in mind, the operator requests that the previously submitted plan and mining depth for the RI2A be approved ati submitted. The operator thanks DMG for its suggestion on the mini .g depth and will evaluate its potential if market demand lessens considerably. Item 7 -Spill Containment and Countermeasures Plan A Spill Containment and Countermeasures Plan is being prepared. This plan will be submitted to DMG, Garfield County and the City of Rifle when it is completed. Item 8 - Storntwater tnanagetttent In the active pit azeas, any detention ponds' constructed will be temporary sutce these pond(s) will be located in the dry section of the pits. The dry section ofthe pits will he mined out as the resource below the water table is removed. The portions of the pit with groundwater e~tposed will also be used to detain stormwater to settle suspended solids. Arty sediment in the stotmwatcr will settle out in the pit due to the retention time. The retention time is expected to be long as the velocity of the water through the alluvium is quite low. In addition to the long retention times, the undisturbed sand and gravel will act as a 6her to remove any suspended solids when water leaves the pit area as groundwater.