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Response: Attachment C, Sheets 13-17,provide an updated and detailed design of the <br /> excavation areas. It should be used in lieu of Figures 3-3 and 3-4 <br /> Comment No. 22 - Pursuant to Rule 7.3.2,please commit to providing the Division with <br /> certified verification by a professional engineer or other appropriately qualified professional <br /> that will confirm the WRPs and all surface water diversion structures were constructed in <br /> accordance with the approved design. <br /> Response: Cotter commits to providing the Division with certified verification by a <br /> professional engineer or other appropriately qualified professional that will confirm the <br /> WRPs and all surface water diversion structures were constructed in accordance with <br /> the approved design. <br /> Comment No. 23 - Pursuant to Rule 6.4.21(7)(e),the effectiveness of each Environmental <br /> Protection Plan facility is to be evaluated through monitoring systems. The Schwartzwalder <br /> Mine has in place a comprehensive surface and ground water monitoring plan designed to <br /> measure and identify potential sources of uranium contamination. However, there are no <br /> monitoring wells in the immediate vicinity of the north WRP. The Division recommends the <br /> Operator install a groundwater monitoring well into the north WRP or immediately adjacent to <br /> it. Please provide the Division with a plan for installing a monitoring well into the north WRP <br /> or otherwise specify how the effectiveness of this EPF will be assessed. <br /> Response: Cotter has been monitoring Ralston Creek from points upstream and <br /> downstream of the WRPs for many years. Analytical results indicate that neither WRP is <br /> contributing contaminants to Ralston Creek to any appreciable degree. Therefore,the <br /> need for a monitoring well is not warranted. Furthermore, drilling through the waste rock <br /> pile poses a greater risk of contamination than leaving the WRP intact. A monitoring <br /> well, over time, could become a conduit for surface water to flow along the well bore to <br /> the groundwater, bringing with it, dissolved constituents from the WRPs. <br /> However, when flow is available, Cotter will sample Ralston Creek at a location <br /> immediately downstream of the north WRP. Sampling at this location will isolate any <br /> potential impacts to the creek from the north WRP when water is flowing through the <br /> stream channel. Cotter designates this sample location as SW-NWRP. <br /> August 2,2016 Comment Letter <br /> Comment No. 1 - Page 51, Small Gulch Energy Dissipater. Apparently the previous <br /> plan was to collect runoff from the small gulch above the East Waste Rock Pile and <br /> discharge it through a spillway causing it to spread out into sheet flow over the waste <br /> rock pile. This concept will not work. The waste rock piles are considered <br /> environmental protection facilities (EPFs). As such, stormwater must be diverted <br /> around the waste rock piles in channels designed to convey the peak discharge resulting <br /> from the 100-year,24-hour design precipitation event. <br /> Comment No. 2 - Page 52, Section 7.2.2. This section states riprap is sized and <br /> gradation provided on Sheet 3 of 5. No such information could be found on Sheet 3 <br /> 2016-1 1-07 Response to TR23 Adequacy Review 9 <br />