Laserfiche WebLink
Responses to Division of Mining Reclamation and Safety Adequacy Review Letters Dated June 26, <br />2013 and July 3, 2013 <br />By C. A. Braun - July 25, 2013 <br />Response to June 26, 2013 Preliminary Adequacy Review — Environmental Protection Plan <br />General Comment 1 "EPP discusses unoxidized vein material that may contain up to 5 percent iron <br />sulfide. DRMS is concerned about surface stockpiling ... a pad shall be designed to contain direct <br />precipitation from 100 -year 24 -hour storm... " <br />Response: <br />When considering storm runoff, our experience has found that we need to generally look at both short <br />term and long duration events and base our designs on both results. United Stated Department of <br />Commerce (USDOC) Technical Paper 40 shows the following precipitation amounts for the mine site. <br />The 100 -year 1 -hour event is shown to be 1.75 inches and the 100 -year 24 —hour event to be 3.5 inches. <br />This number compares well with the National Oceanic and Atmospheric Administration (NOAA) Atlas II <br />value. A review of the 100 -year 6 -hour event in that document shows that the majority of the <br />precipitation at this local is anticipated to be over a short time frame. Notable recorded storm events <br />included on in late May 1894 (3.1 inches in 24 hours at Glen Eyrie, July 30, 1895 (amount unknown at <br />Victor), July 12, 1912 (amount unknown in Cripple Creek and Victor), June 4, 1921 (2.1 inches in 24 <br />hours at Victor). The precipitation events were the results of summer thunderstorms. These recorded <br />events indicate that the published numbers are reasonable and conservative. Per regulations, the 24- <br />hour 100 year event will be used for permit designs. <br />1a Provide a discussion on potentially impacted water treatment and /or disposal <br />Response: <br />Exhibit C notes that the ore material will be stored underground in an ore bin. It goes on to say that the <br />material will then ... be hauled to the portal for temporary storage." At the portal, it is anticipated that <br />ore will be loaded directly out of the mine onto trucks, and as a result, there will be no surface storage <br />of sulfide ores. Further, the words "iron sulfide" was used in the permit application to be complete and <br />consistent with the company's hopes that future exploration might identify sulfide ores. However, at <br />this time, the project is still in exploration stage and not yet in production mining stage. Exploration to <br />date has not identified any sulfide- containing vein material that can be classified as ore. Since no sulfide <br />ore currently exists, and that if any is ever found, it will not likely be stored outside of the mine. In the <br />1 <br />