2025-03-14_PERMIT FILE - M2025016 (13)

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// PAGE 1 EXHIBIT G Raptor Materials, LLC Cogburn Sand, Gravel, and Reservoir Project February 2025 A Regular Impact (112) Construction Permit Application – Colorado Division of Reclamation Mining and Safety, Office of Mined Land Reclamation Exhibit g – Water Information SECTION 1 If the operation is not expected to directly affect surface or groundwater systems, a statement of that expectation shall be submitted. Operations will not adversely affect surface and groundwater systems. Measures described in the Cogburn Application and particularly in this Exhibit G, and also in Exhibits D and E are intended to minimize disturbances to the prevailing hydrologic balance of the affected land and of the surrounding area and to the quantity or quality of water in surface and groundwater systems both during and after the mining operation and during reclamation. The manner and method of extraction is detailed under Exhibit D – Extraction Plan. Anticipated effects on surface flows are anticipated to be minor to none. Essentially, the floodplain covers a majority of the property and unless under flood conditions, upland overland flows are generally diverted by levees, surrounding roads, or grassed drainage channels; or otherwise by draining internally into existing or planned basins. Considerable efforts are made to control storm flows, including the use of grassed waterways. Some rilling will occur on cut slopes, but the sediment is inbound. A minor 6-inch furrow above cut slopes will create a 1- foot swale that could minimize such rilling, especially valuable on reclaimed slopes above the final estimated water level of the basins. The stormwater management plan referenced in Exhibits I and J will address broader water management covering any piles of soil or inert fill constructed external to the excavations. Impacts to groundwater and area wells from groundwater discharge during mining was evaluated by AWES, LLC in their October 2024 report, as included in this submittal. The report concludes: “Dewatering multiple pits at the maximum predicted drawdown (Cells A&B) will likely have the greatest drawdown effects. It is anticipated that cell closure of one mine cell (Cell C) will occur during the mining and dewatering of the adjacent pit B, which will mitigate drawdown issues. Post lining head levels immediately up and downgradient of the lined pits are within the range of normal seasonal water table elevation changes. Predicted water level depressions (shadows) varied between -0.15 and -1.44 feet and predicted mounding was estimated at 0.05 feet for the three lined pits. The modeling results indicate that shadow-mounding effects of lining post extraction pits will not adversely affect the regional groundwater hydrology.” POST RECLAMATION IMPACTS have been minimized: The AWES Mining and Water Storage Analysis report of October 2024 evidences that there will be no measurable impacts of either shadowing or mounding of the resulting lined basin. The operation therefore includes lining of the basin during reclamation of the resulting basin. Satisfaction of Colorado State Standards as to the integrity and functionality of the resulting lined basin will be made in cooperation with the Colorado Division of Water Resources, and any resulting submittals and approvals made available to the OMLR at the time of the Annual Report, or by separate cover. No measurable impacts to the prevailing hydrologic balance are foreseen. SECTION 2 If the operation is expected to directly affect surface or groundwater systems, the Operator/Applicant shall: