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As has also been known for many years by professionals, what little xanthate might <br /> remain in the tailings sand degrades rapidly, and the on-site testing that was performed in <br /> response to the CMLRB confirmed this fact. <br /> As the facility uses a minimum amount of water for processing, both the material that is <br /> to be retained and the material that is to be discarded is dewatered, and the water is <br /> recycled and reused. As was observed by the DRMS inspectors during their summer of <br /> 2020 inspection, the discarded sand had been placed using a loader bucket and had been <br /> dewatered to below saturation before placement. Chemically, the material has <br /> approximately the same composition as the waste rock and is simply finer-grained. The <br /> original analysis that was performed on the material prior to obtaining the 2015 permit, <br /> and the recent DRMS ordered resampling found the concentrations of target metals <br /> remaining in the tailings sand to be approximately equal to the concentration naturally <br /> occurring in the soils in the area adjacent. Thus the tailings sand is to be recombined <br /> with the coarser grained material in the waste rock pile. Alternatively, since this tailings <br /> sand material has been found to be suitable as a growth media, if during reclamation <br /> insufficient soil is found, the material can be stockpiled and used as a supplement to <br /> existing stockpiled soils. <br /> Since the Earth's rocks are not necessarily homogeneous, neither is the content and exact <br /> composition of the minerals in those rocks. Successful milling requires the <br /> maximization of all parameters that perfect efficient recovery and the fine tuning of a mill <br /> is dependent on the professional operating it. Therefore, the operation needs to operate <br /> with the best technology possible. The chemical xanthate, had been in use on the site <br /> since the original permit was issued and prior to the DRMS 2020 inspection. In the <br /> future, it might still turn out to be the best collector, or alternatively, it might still be <br /> necessary to use it along with other equally environmentally friendly reagents. Most of <br /> the chemicals used for this type of mineral processing are generally very similar <br /> chemically, thus consist of families of chemicals that have similar characteristics with <br /> varying compositions of the key ingredients. Some manufactures provide all of the <br /> information concerning their products and some label precise compositions as <br /> proprietary. Once again neither xanthate, nor any of these standard organic compounds <br /> generally used in flotation are listed as hazardous by EPA or CDPHE, and no negative <br /> environmental problems have occurred when these chemicals have been used according <br /> to the manufacture or distributor's recommendations. Safety Data Sheets (SDS) for the <br /> chemicals that will be used, or are currently anticipated to be used, are included in the <br /> Environmental Protection Plan. Since other proprietary reagents might have a different <br /> 6 <br />