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Ms. Katie Todt <br /> February 9, 2026 <br /> Page 3 of 9 <br /> The material is first processed on a large mesh screen, and the smaller materials will go to a <br /> hopper that feeds a trommel, where it will be washed. Finer materials containing gold will <br /> fall into the sluice box below the trommel, while the larger materials will be conveyed to a <br /> gravel heap for eventual disposition into mined out excavations. <br /> This SWSP is for operations associated with the southern processing area and wash plant, and <br /> the west processing area and wash plant. The mine will now operate pursuant to a single <br /> sitewide SWSP for the entire Box Creek Placer Mine. A maximum of two gold processing <br /> plants will be in operation at any given time. <br /> Depletions <br /> Depletions from the site consist of evaporative depletions of exposed groundwater, <br /> processing pond evaporation, first fill inflow, material processing and dust suppression. The <br /> Applicant has calculated the evaporation rate at the site to be 40 inches per year based on <br /> the evaporation atlases in NOAA Technical Report NWS 33. This mining operation has a <br /> mining permit (M-2018-053) approved by the Colorado Division of Reclamation, Mining, and <br /> Safety under the Hard Rock Mining Act (article 34-32). Mining operations that are permitted <br /> under the Hard Rock Mining Act qualify under section 37-80-120(6) to offset gross <br /> evaporation losses by the amount of depletions that would have occurred due to pre-existing <br /> natural vegetative cover that has been eliminated. In this case, an offset of effective <br /> precipitation based on precipitation data from the Twin Lakes Reservoir climate station was <br /> applied to gross evaporation, resulting in a net evaporation amount of 33 inches per year <br /> that was used to calculate evaporative depletions to be replaced under this SWSR <br /> Therefore, the anticipated annual depletion calculations are: <br /> Plant Settling Ponds: 1.0 ac x (40"/yr evap - 6.73" eff. ppt)(1 ft/12") x 2 Ponds = 5.54 AF <br /> Exposed GW (Drone Image): 6.13 ac x (40"/yr evap - 6.73" eff. ppt)(1 ft/12") = 17.0 AF <br /> Dust Suppression: 30 ac disturbance x 0.15 AF/ac = 4.50 AF <br />