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7 Groundwater Information <br /> The following section gives a brief overview of the groundwater system in the vicinity of the <br /> Mine. More detail about the groundwater system may be found in Exhibit G. <br /> 7.1 General Area Discussion <br /> Groundwater in the Revenue Mine area is almost completely supplied by infiltration of high- <br /> elevation surface water seeping through fracture systems in the area. No sedimentary aquifers are <br /> found in this area. Additionally, the groundwater regime is strongly influenced by historical <br /> mining activity. Since documentation of pre-law mines is incomplete, it is not possible to provide <br /> a complete inventory of groundwater sources and flows. From historical documentation of the <br /> Revenue/Virginius mining activity in the area, it is known that the original Virginius mining area <br /> is located above and is connected to the Revenue tunnel. Other mines exist in the Sneffels Creek <br /> drainage above the Revenue tunnel, such as the Atlas Mine, Ruby Trust, Lower Mountain Top, <br /> Upper Mountain Top, and Humboldt. These features do not connect via mined passages but may <br /> have hydrologic connection via naturally occurring veins and fractures. The Lower Mountain <br /> Top and Ruby Trust each have substantial water discharges that are either permitted or were <br /> permitted at one time under the Colorado Discharge Permit System. Below the Revenue Mine is <br /> the Camp Bird, a significant, year-round groundwater drain of the Six Basins area. <br /> Within the Sneffels Creek drainage lies the Atlas Mine, Torpedo Eclipse Mine, Bimetallist Mine, <br /> Virginius Mine, Humboldt Mine, Ruby Trust, Smuggler Mine, the Mountain Top Mine, the <br /> Lower Mountain Top Mine, and the Liberty, among others. The area has been mined since the <br /> late 1800s. Substantial pre-law waste rock piles may be found throughout the area. The recently <br /> reclaimed Atlas Mill tailings lie immediately upgradient of the Revenue portal. <br /> See Map G-1 for tributary water courses, wells, springs, etc. on the affected lands boundary and <br /> within 2 miles. <br /> 7.2 Known Aquifers and Related Subsurface Water-bearing Fracture Systems <br /> There are no known aquifers in the area. Rather groundwater flows through fractured bedrock <br /> and historic mine workings. Groundwater flow is highly influenced by fractures and faults but is <br /> generally towards surface water features including Sneffels Creek. <br /> 7.3 Site Geology <br /> The Revenue Mine's local geology is predominantly controlled by fracture structures that cross <br /> the various volcanic formations in the area. The veins of the Sneffels district seem to occupy <br /> structures that are related to the San Juan and Silverton Calderas, they are radial and concentric <br /> structures extending for several miles northwest of the actual caldera margin. These structures <br /> M-2012-032 <br /> Amendment 02 Exhibit U <br /> December 2021 U-17 <br />