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D-27 <br /> ROM stockpile material will be recovered via front-end loader, and introduced to the "wet plant", which <br /> will utilize mechanical separation processes (fresh water wash) to produce a#30/#140 (i.e., less than 30 <br /> mesh but greater than 140 mesh)interim product. <br /> Oversize material(i.e.,that greater than 30 mesh)will be scalped off prior to the wash process and routed <br /> to the reject stockpile. <br /> Undersize material (that less than 140 mesh but greater than 325 mesh) will be separated with cyclones, <br /> dewatered to less than 20%moisture and conveyed to the reject stockpile. <br /> Ultra-fines(#140/325)will be generated during the wash process(which will employ cyclones and attrition <br /> cells)and contained in plant effluent. Plant effluent will be processed in a rack clarifier,with clean water <br /> recycled back to wet plant supply tank. <br /> Thickened sludge will report to belt presses where further dewatering will occur. The resulting filter cake <br /> will be conveyed and stockpiled at the plant. <br /> The retained material(i.e.,that less than#30) would then be pumped to a series of attrition cells to break <br /> down clusters and separate undesirable "clayey" materials from the desired silica product. The slurried <br /> material will then be pumped to a series of cyclone separators,from which overflow will report to the water <br /> clarifier. Cyclone underflow will produce a #30 x #140 product, which will be screen-dewatered and <br /> conveyed to the Wet Sand Storage Building(as an interim product)for decanting and subsequently,removal <br /> for further (downstream) processing. The cyclone overflow, a #140 x #325 waste fines slurry, will be <br /> dewatered and conveyed to the reject(process waste) stockpile. <br /> [Note: During upset conditions, sludge will be pumped from the clarifier to a holding cell ("HC-1") <br /> constructed in the pit floor. Once HC-1 is full, as second cell(HC-2) will be created and all conveyance <br /> piping reallocated to the second cell. HC-1 will be allowed to naturally dewater thru the combined effects <br /> of evaporation and infiltration, and once "dry", will be cleaned out with excavators and trucks. Material <br /> will then be hauled to either the process waste stockpile or a proximal pit floor location,if available. Once <br /> HC-1 has been cleaned out,it can be put back into service for subsequent upset conditions,and HC-2 will <br /> follow the same procedures for clean out.] <br /> Keenesburg No. 2 Mine_112 Reclamation Operation—November 22, 2019 <br />