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each point via email dated February 12, 2021. The length of time that went by between the adequacy <br /> review letter and the response to was the result of delays from the testing laboratory that was having <br /> problems related to equipment, along with the effects on their business by the Chinese virus. Braun's <br /> report concluded that the sand produced by the mill met environmental regulations, and that the most <br /> environmentally sound disposal method was to place it on site. That response also included the <br /> Tailings Handling Plan that had been ordered, which describes the methods to be used to place the <br /> tailings sand. <br /> A second adequacy review was sent out via email by Elliot Russell on March 4, 2021, requesting that <br /> the manufacturer's recommendations for storage be provided. Braun Environmental responded on <br /> March 9, 2021, provided the Safety Data Sheet(SDS)for xanthate that included storage instruction, <br /> and reiterated that the Operator had been storing the material in conformance with the <br /> recommendations contained on the SDS. <br /> As has been discussed previously,both EPA and CDPHE consider the chemical to be non-hazardous, <br /> and thus they do not regulate it. Should the operator want to dispose of it, it can be sent to any <br /> Colorado Subtitle D solid waste facility and handled as a simple solid waste. Further, since neither <br /> agency considers it to be hazardous, they have set no standards for concentrations in soils. As a <br /> result, even if detectable concentrations of xanthate should remain in the tailings sand,based on those <br /> regulations, it would pose no threat to human health or the environment. The only consideration <br /> would be if the concentrations remaining in the material would exceed the ecotoxicity standard for <br /> freshwater fish, and that the material would be in direct contact with aquatic habit. This site is <br /> located nearly 6 miles distant from the closest downgradient perennial stream, so even if residual <br /> xanthate might remain in the material, no mechanism exists for xanthate to reach aquatic habitat. <br /> In summary, the investigations found the milled sand material that had been placed on the waste rock <br /> pile meets environmental standards of CDPHE and EPA, and specifically the CDPHE standards, with <br /> respect to its location in the Cripple Creek area. Therefore,based on the investigations and the <br /> applicable environmental regulations,the optimal method and most environmentally friendly way of <br /> returning this material back to the environment is to place it in the on-site waste rock pile. <br /> Specific amendments to the original plan are as follows and are shown by section. Sections where no <br /> changes are necessary are identified by "No changes". <br /> 1. INTRODUCTION TO AMENDMENT (6.4.21(1) <br /> No changes <br /> 2. MAPS (6.4.21(1) <br /> One map is added to the Plan - On-Site Chemical Storage Map <br /> 3 OTHER AGENCY'S ENVIRONMENTAL PROTECTION MEASURES AND <br /> MONITORING <br /> No changes <br /> 4 OTHER PERMITS AND LICENSES <br /> No changes <br /> 2 <br />