2017-03-23_PERMIT FILE - C1981019A

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RULE 2 PERMITS As discussed below, there is a slight chance for a spring to develop in Little Collom Gulch during the post -mining period if the pit backfill re -saturates up to the elevation that the northern pit highwall daylights in Little Collom Gulch. This spring would discharge groundwater from the mine backfill material. Further evaluation is provided under the discussion of potential impacts to groundwater. West Fork Jubb Creek Area There are no mapped springs in the West Fork of Jubb Creek drainage that will be directly eliminated by the mining activities. As indicated in Table 2.05.6-4, spring V1 is not a naturally occurring feature. It is a flowing well (Well Permit No 175218) located in the stream valley at about elevation 7170 ft and is completed at a depth of at least 600 ft below ground surface. Based on the data fromavailable drill logs in the area the well is completed in the Trout Creek Sandstone. The Trout Creek Sandstone aquifer will not be affected by mining so the flow in this well would not be impacted. Springs V10, and V32 are located at elevations 7295 ft and 7600 ft, respectively, along the West Fork of Jubb Creek and on the west side of the stream channel. However, the spring elevations are generally above the bedrock groundwater elevations and are likely sourced locally so impacts from dewatering the bedrock groundwater system are unlikely. Spring V2 is located at about elevation 6860 ft on the west side of the West Fork of Jubb Creek. It is north of the mine area and is likely sourced from local recharge. It is located within the Collom Haul Road corridor and will likely be impacted to some degree during the construction of the road. Springs V3, V9a and V9b are also located well north of the mine area at elevations 6820 ft, 6895 ft and 6886 ft, respectively, along the east side of the stream channel. These springs are sourced from areas to the east of the stream and are not expected to be impacted by the mining activities. Two springs potentially affected by mining operations (V10, and V32) produced a combined average flow of about 0.013 cfs, a maximum flow of about 0.022 cfs and a minimum flow of about 0.004 cfs during the baseline monitoring period. It is not expected that new springs will develop in the West Fork of Jubb Creek during the post -mining period. Collom Creek Area There are no mapped springs in the Collom Creek drainage that will be directly affected by the mining activities. Springs SPRC-02 (V8), V27, V28 and SPRC-04 (V7) are located at elevations 6807 ft, 6701 ft, 6696 ft and 6601 ft, respectively, along the east side of Collom Creek north of the mine area. There is a small chance for the flow in these springs to be reduced as a result of the mine dewatering activities intercepting bedrock groundwater flow that may feed the springs. However, they are more likely sourced from local groundwater that will not be affected by mining. Springs SPRC-03 (V26), V20, V21 and V25 are located at elevations 6753 ft, 7074 ft, 7076 ft and 6785 ft, respectively, along the west side of Collom Creek. These springs are sourced from areas to the west of Collom Creek and are not expected to be impacted by the mining activities. Other springs listed in Table 2.05.6-4 are located up -gradient of the mine and are likely sourced from shallow groundwater and are not expected to be impacted by the mining activities. Collom — Rule 2, Page 112 Revision Date: 11/16/16 Revision No.: MR -166