2021-04-15_REVISION - M2014045 - Laserfiche WebLink

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BRIEF DISCUSSION OF AMENDMENT On June 2, 2020, Division of Reclamation and Mining Safety(DRMS)personnel performed a site inspection, and conducted a follow-up on July 15, 2020. On August 19, 2020, the Colorado Mined Land Reclamation Board(CMLRB)found the Operation in violation of C.R.S. 34-32-124 for failure to comply with a permit. The CMLRB ordered that the Operator file a Technical Revision within fifteen days of mailing of the Order to propose a plan to appropriately dispose of xanthate and flotation concentrate currently stored on site, and to either excavate and haul uncharacterized mill tailings off-site to an appropriate disposal, or have a third party sample and characterize the mill tailings to determine if they can be left in place. Second, the Order required that Operator file an Amendment Application updating the Mine Plan and Environmental Protection Plan to describe current and proposed mining and milling activities at the site. The operator immediately contacted professionals and began site investigations and testing of those materials that had been identified by DRMS personnel. The testing found that the regulated metallic elements remaining in that material identified by DRMS met all normal U.S. Environmental Protection Agency(EPA) and Colorado Department of Public Health and Environment(CDPHE) standards for all metals of concern, with exception of arsenic. Since arsenic concentrations in Colorado tend to normally be elevated above the EPA regulatory levels, CDPHE recognizes this and sets an elevated level that corresponds with the natural background levels. The testing found that the material contained either similar concentrations, or even reduced concentrations of arsenic as compared to the sampling that was conducted on nearby rock outcrops within the permit areas. Investigations were also begun on residual xanthate. Xanthate is a simple organic compound, and since neither the EPA nor the CDPHE consider xanthate to be a hazardous substance or a hazard to the environment, no standardized or government approved standardized tests have ever been developed to test for it. In conjunction with CDPHE and private laboratories, the consultant developed a test specifically to satisfy the CMLRB order. The testing found no detectable concentrations of xanthate in the processed sand that had been placed on the waste rock pile, nor did it find any in the evaporated residue that remained from the original operating fluids that were identified within the mill circuit during the previous DRMS inspections. This result was predictable, since the xanthate concentrations used for processing were very low to start with, the compound would be expected to be retained with the product produced by the mill, and typical of many small organic molecule,it tends to naturally rapidly degrade. These results were reported to DRMS via a letter report produced by Braun Environmental, Inc., on October 30, 2020. In an Adequacy review dated November 13, 2020, Elliot Russell of DRMS requested additional information on the following: 1 Xanthate storage; 2 Disposal of xanthate residue from evaporated process water; 3 Information concerning transport of flotation concentrates off-site; 4 Plan for handling mill tailings; 5 Collection of background samples for arsenic, and; 6 Additional testing acid based accounting of tailings materials. In response to the review, additional sampling and testing was then performed to address these comments, and upon receipt of the results from the laboratory, Braun responded in a letter report to 1