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4 <br /> <br />4 <br />Trapper Mine PR8 Preliminary Adequacy Review <br />Prepared by: R. Reilley July 2017 <br />approval to mine in the PR-7 area. Site specific information relative to geologic characteristics of the <br />proposed mining area will be submitted as a revision at the same time that a mining plan that includes this <br />area is submitted. <br /> <br />TMI has completed a study of overburden characteristics for the PR-7 area. Pages 2-391a through <br />2-391z are proposed to be added to the permit document which insert a new Section, Section <br />2.7.2.3, Overburden Geochemistry of the PR-7 Mine Expansion Area. The inserted section includes two new <br />figures (Figures 2.7-4a and 2.7-4b) and three new tables (Tables 2.7-Sa through <br />2.7-Sc). Section 2.7.2.3 provides a summary of the PR-7 Mine Expansion Area overburden <br />geochemistry testing and discusses the overburden geochemical testing specific to that area. <br /> <br />The overburden testing program was discussed with the DRMS in a meeting on April 14, 2014 and <br />agreement reached on the number of drill holes and that the overburden will be evaluated for its potential <br />suitability as either a plant growth medium or regraded spoil aquifer based on a number of published criteria <br />as listed in new Section 2.7.2.3. One drill hole was used for the program and the location of that hole is <br />shown on Map 36. Seventy-six (76) overburden samples from the PR-7 Mine Expansion Area were <br />analyzed for 30 physical and chemical parameters in this evaluation. <br /> <br />The evaluation found that the overburden materials within the PR-7 Mine Expansion Area are suitable for <br />reclamation and are essentially free of constituents that pose a threat to plant growth, surface water, and <br />groundwater. Once the overburden materials are mixed via mining and further mixed via regrading and <br />reclamation operations, they will be at least of an equal, if not better, physical and chemical quality than the <br />topsoil currently found on this site. <br /> <br />July 2017 DRMS <br />Trapper is not requesting to mine the PR-7 area with this revision. <br /> <br />3. The operator states that additional geologic information will be provided as a revision at <br />the time the mining plan is submitted. <br /> <br />A study of overburden characteristic has been conducted, and a new section added for the <br />Overburden Geochemistry of the PR-7 Expansion Area. Core hole data is provided and a map <br />included. <br /> <br />This section of the stipulation is adequately addressed. <br /> <br />May 2017 Trapper <br />d) Surface water information in the hydrology description with water quality data from surface waters in, <br />discharging into, or which will receive flows from surface or ground water from affected areas within the <br />proposed permit area in accordance with Rule 2.04.7(2)(b)(ii). <br /> <br />As described in Section 2.7.4.1, on updated Page 2-4141 previously provided as part of adequacy response to <br />PR-7, no perennial or intermittent flows have been recorded in the Deacon Gulch and Jeffway Gulch <br />drainages within the expansion area. That discussion has been updated to provide additional information for <br />this submittal and a revised Page 2-4141 is included with this letter. As part of the additional information, <br />Table 2.7-12c is being added to the permit document as page 2-414m to show the dates when flows have <br />been observed for both gulches. Figure 2.7-15f as page 2-414n is being added to the permit document to <br />show the location of observation points for flows in both Deacon Gulch and Jeffway Gulch. <br /> <br />Further downstream from the PR-7 permit boundary the Deacon Gulch drainage becomes more incised and