Laserfiche WebLink
4. The Applicant has indicated the mine will be operated more than 180 days per year. Please <br /> note that if the Operator does not designate the mine as an intermittent operation, then the <br /> operation will need to comply with the provisions of Rule 1.13.1. <br /> The mine will operate as much as possible based on weather. Many seasons may be shorter than <br /> 180 days, so the applicant requests to designate the mine as an intermittent operation. <br /> S. Under Section 10.1—Surface Water, the Applicant has stated the diversion ditch has been <br /> designed to convey the uphill runoff of a 100-YR/24HR storm event. However, the <br /> SEDCAD Reports show that the diversion ditch, collection ditches and sediment pond are <br /> designed for a IOYR124HR storm event. The Division will require all storm water control <br /> features to be designed for a IOOYR124HR storm event. Please make the appropriate <br /> changes to the design of the stormwater control features. <br /> Please see the attached revised SEDCAD designs for the Diversion Ditch. <br /> 6. The Applicant has indicated a steel door with a lock will be installed on the portal.Any <br /> closures which are not currently in place must be included in the financial warranty <br /> estimate. Please revise the financial warranty estimate accordingly. <br /> See the revised page D-3. <br /> 7. The Applicant has stated water for the mining operation will be purchased from the Town <br /> of Alma. However, Section 8 of the revised Mining Plan still states that water will be <br /> pumped from Buckskin Creek. Please revise the Mining Plan accordingly. <br /> See the revised page C-3. <br /> 8. The Applicant is proposing to advance the existing portal by 400'and the portal will <br /> intersect several veins and faults. The Applicant has stated that groundwater will not be <br /> intercepted, but has not made any further demonstration that water will not be produced <br /> from mining activities. According to the Colorado Upper Mine Assessment Project Report <br /> (2010)provided by the Applicant, many of the portals in Buckskin Gulch discharge water. <br /> In addition, the mineral targets for Detroit City Mine are veins and faults which can act as <br /> conduits for water. Therefore, the Applicant shall provide a plan addressing a potential <br /> discharge of water from the mine. The plan shall specify how the Applicant will comply <br /> with the requirements of Rule 3.1.7, as well as the requirements of the Water Quality <br /> Control Division. <br /> See page C-6, specifically the grouting plan. <br /> 9. In response to the Division's Preliminary Adequacy Review Letter, the Applicant has <br /> committed to conducting geochemical testing of the waste rock to determine the potential <br /> for acid generation. The geochemical characterization of the waste rock must be conducted <br /> prior to any placement of waste rock in the WRL. Please provide a sampling plan for both <br /> acid-base accounting and whole rock analysis. The plan shall also include a proposed <br /> timeline for conducting and reporting the results of the geochemical tests. <br /> The applicant will conduct Acid-Base Accounting and whole rock analysis according to the suite <br /> attached to this response. <br /> 2 <br />