2024-05-23_PERMIT FILE - M2024025

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Wild Horse Reservoir Project West Test Quarry DRMS 111 Application 3.2 Mining Plan NOTE: DRMS Guidance from Rule 6:Permit Application Exhibit Requirements is shown in italics for each section. 3.2.1 Timetable 6.3.3(a) specify the estimated dates that mining will commence and end. If the operation is intended to be an intermittent operation as defined in C.R.S 34-32.5-103(11)(b), the Applicant should include in this exhibit a statement that conforms to the provisions of Section 34-32.5-103(11)(b), C.R.S.; Mining in the West Test Quarry area is expected to begin after all required permits are obtained. Mobilization is expected on or around July 15, 2024. In general, mining of the West Test Quarry will proceed starting with the West Test Quarry Section 1 and commencing to the West Test Quarry Section 2. The operation is scheduled to have completed demobilization from the site by the end of 2024, assuming no unforeseen schedule impacts (or no later than November 2025). The mining operation is not intended to be an intermittent operation. The figures on the two (2) pages at the beginning of Exhibit C (Section 3.1) illustrate the mining condition with a test quarry floor at Elevation 9270 for Section 1 and Elevation 9120 for Section 2. Throughout mining, the quarry floor elevation topography will be graded to promote runoff from disturbed areas to the topographic lows at the Wild Horse Reservoir Project site.The overall timeline for mining the West Test Quarry is planned to be 4.5 months. The total combined area of the West Test Quarry (5.25 ac)will be completed in one stage of mining. 3.2.2 Plant Growth Medium 6.3.3(b) the estimated depth to which soil, suitable as a plant growth medium, will be salvaged for use in the reclamation process. This description must be consistent with information provided in Exhibit B. Sufficient soil must be salvaged to meet the vegetation establishment criteria of Rule 3.1.10. If plant growth medium is not reapplied on a graded area immediately after salvage, then the Operator/Applicant must specify how the topsoil will be stockpiled and stabilized with a vegetative cover or other means until used in reclamation. Plant growth medium stockpiles must be located separate from other stockpiles, out of the way of mine traffic and out of stream channels or drainage ways. The location of plant growth medium stockpiles must be shown on Exhibit E—Map In the Test Quarry area, there is typically less than 0 to 11 inches of surficial soils on 3 to 40 percent slopes. The surface soils are expected to be a suitable plant growth medium, and thus will be salvaged for use in the reclamation process. Underlying the surface soils is a layer of residual soil/weathered bedrock from approximately 1 to 5 feet below existing ground surface. The residual soil is not expected to be a suitable plant growth material. The majority of the disturbed area has a soil classification of Betermer. The majority of the bedrock is an igneous quartz monzonite porphyry. Existing surface soils will be removed and stockpiled away from the test quarry sections before excavation and will be kept free from trash, debris, or other material which may be harmful to plant growth. These surface soils will be stockpiled at the Common Processing Area shown on Exhibit E for later use during reclamation; during mining operations,the stockpiled soils will not be placed along haul routes, stream channels, or other traffic and drainage ways. 3.2.3 Waste Rock and Residual Soil 6.3.3(c)specify the thickness of overburden or quantity of waste rock, if any, to be removed to reach the deposit. The location of any overburden stockpiles or waste rock fills must be shown on Exhibit E—Map. It is expected that between 5 and 20 feet of overburden, or residual soil, will be encountered below the suitable plant growth medium. In areas where no suitable surface soil plant growth medium exists, there may be between 0 and 10 feet of overburden, or residual soil. TETRA TECH May 2024 9