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Max Velocity (mm/s) 2.202617861 <br /> 3.6 Ore Handling <br /> Ore is delivered directly to the underground mill. No ore will be stored on the surface. The mill <br /> will process approximately 120,000 tons of ore per year. Details of the mill process are discussed <br /> in Section 4 of this Exhibit D. Mill Operations. <br /> The general process flow of the mill is described below. More detailed descriptions of the mill <br /> operations may be found in TR-15. <br /> The Revenue Mill is designed as an underground mill with a 540 ton per day of ore capacity. The <br /> Mill area excavations (four tunnels that constitute the mill complex) include: <br /> 1) The mine car unloading tunnel and coarse ore bin with slusher; <br /> 2) The crushing gallery with conveyor leading to the mill tunnel (fine ore bin incline), <br /> 3) The mill tunnel, which contains two flotation circuits (lead and zinc) and leads to the <br /> filter building at the outside edge of the mill tunnel; and <br /> 4) The decline tunnel,which provides equipment access to the crushing gallery from the <br /> mill tunnel. <br /> The original mill was designed by CH2MHi11 in Denver, Colorado based on ore samples and <br /> production targets for the mine and mill. Tunnel excavation began in March of 2013. Installation <br /> of mill concrete flooring, crushers, screens,ball mill, flotation cells,water handling systems, <br /> filter presses, control room,reagent storage, and electrical room equipment occurred in April of <br /> 2014. <br /> Barr Engineering of Minneapolis,Minnesota updated the mill design in 2017 under OSMI <br /> direction. Mill upgrades were necessary to improve ore recovery. TR-09 permitted replacing the <br /> previous single stage jaw crusher followed by a cone crusher with two-stage jaw crushers and a <br /> rod mill to prevent clogging with fines. The original cyclone circuit was inadequately sized to <br /> achieve the correct operating pressure given the expected tonnages; the screens that were <br /> approved under TR-09 are not reliant on operating pressure. Changes in the flotation system <br /> were also needed based on two years of successive metallurgical testing,which proved that <br /> changes in reaction time and reagents will improve metal recovery from the ore. As permitted in <br /> TR-09,the mill filter building was expanded to house a compressor room and reagent room as <br /> well as a small roof structure over the transformers near the mill entrance. <br /> A simplified flow diagram that outlines the milling process is found in Figure 1. A detailed flow <br /> diagram of the milling process is found in drawings that were submitted to DRMS as part of TR- <br /> 15. <br /> Revenue Mine <br /> Amendment 02 D-10 <br /> Updated August 2022 <br />