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Mr. Connor Drinkard <br /> RE: Carr Pit East M-2022-005 <br /> June 27, 2022 <br /> temporarily filled for construction of the access road or elevated conveyor to Phase II. <br /> However, prior to any disturbance within areas identified as potentially containing <br /> jurisdictional wetlands or other waters of the U.S., a jurisdictional wetland delineation will be <br /> performed, and an appropriate Clean Water Act Section 404 permit will be obtained from the <br /> U.S. Army Corps of Engineers to cover the disturbance. A U.S. Army Corps of Engineers <br /> Section 404 approval letter will be included in a permit technical revision submitted to, and <br /> approved by, the Division prior to any disturbance of jurisdictional wetlands. <br /> 11. The embankment of the Lone Tree Creek drainage will not be mined. However, mining to <br /> near the drainage top of bank allows reclamation grading to blend the mine excavation <br /> bottom into the drainage embankment without creating areas where stormwater could pond. <br /> During active mining, an overburden berm approximately 3 feet high will separate the Lone <br /> Tree Creek drainage area from mine excavations, haul roads, stockpiles, and other mining <br /> disturbances. The berm acts as stormwater management and as a safety barrier. Fortunately, <br /> mining at the Carr Pit East site produces rock in varying sizes so rock mats, rock dams, rock <br /> armoring, etc. can be readily used to slow stormwater runoff, stabilize disturbed areas, and <br /> minimize sediment transport. At natural topographic low spots upgradient and adjacent to the <br /> berm, sediment ponds will be constructed to catch stormwater and reduce suspended <br /> sediment prior to discharge into the Lone Tree Creek drainage area. Please see adequacy <br /> review Response#3 for more details. <br /> 12. Exhibit D — Mining Plan is revised to, "The Poudre Valley REA powerline is located along <br /> the southern part of the permit area, adjacent to, but outside of the mining limits." Please see <br /> attached revised Exhibit C-5 —Pre-Mining/Mining Plan Map. <br /> 13. As described in the Nature of Deposit to be Mined subsection, traditional organic topsoil is <br /> thin or non-existent within the mining area. However, within this same subsection, soils and <br /> soil overburden material is described as shallow to deep loams from less than one inch to <br /> over four feet thick. This `soil' and `soil overburden material' should be more accurately <br /> labeled as the overburden material within the mining area. <br /> 14. We believe that all of Phase I (102.7 acres) being disturbed at one time is not accurate. The <br /> concept of concurrent reclamation is specifically directed at quickly reducing disturbed area <br /> following mine excavation. As areas become reclaimed, we believe they are no longer <br /> considered disturbed. The aggregate deposit and environmental conditions at the Carr Pit <br /> East site increases the desire, need, and ability for successful concurrent reclamation. <br /> The applicant's experience aggregate mining in the Carr Pit East area has shown that, to <br /> abate dust and stormwater suspended sediment runoff in the dry and windy northern <br /> Colorado environment, areas disturbed by excavation must be minimized. Since the deposit <br /> being mined is above the groundwater table, reclamation is not hindered by mine dewatering <br /> operations and can proceed quickly after excavation is complete. To minimize material <br /> handling, overburden stripped from a new excavation area is typically placed immediately on <br /> rough graded, previously mined areas. Once soil and overburden growth medium are placed <br /> tb Ue eorth Page 4of12 <br />