2021-06-14_REVISION - M2012032 (3)

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Ouray Silver Mines Inc. Technical Revision 15 May 24,2021 The tails from the Pb circuit are sent to the Zn conditioning tanks(1064 gallons each)where lime from the recirculation circuit is added for a pH adjustment along with CuSO4,Oreprep, and xanthate are added to promote the flotation of zinc and to prepare for the concentrate separation in the Zn rougher flotation tank cell(1320 gallons). The rougher flotation cell mixes air into the slurry with a blower so that Zn can adhere to the bubbles and float to the surface. A concentrate is collected off the top the Zn rougher flotation tank cell and sent to the Zn cleaner flotation cells. Tailings from the bottom of the Zn rougher flotation tank cell report to the Zn rougher scavenger flotation cells. The Zn rougher flotation cells consist of two banks(1320 gallons each). The concentrate from the Zn rougher scavenger flotation cells reports to the Zn cleaner flotation cells along with the concentrate from the Zn rougher flotation tank cell. The Zn cleaner flotation cells consist of two banks(1320 gallons each). Tailings from the Zn cleaner flotation cells report back to the Zn conditioning tank and the concentrate that is produced in this step goes to the Zn cleaner flotation column(214 gallon). The concentrate that is removed from the top of the Zn cleaner flotation column reports to the Zn concentrate thickener. The tailings that are produced by the Zn cleaner flotation column is sent back to the Zn cleaner flotation cell or the Zn conditioning tank,determined by recovery/concentrate grade. Following the Zn concentrate thickener,the concentrate goes to the Zn concentrate filter feed tank(1728 gallons). The concentrate is then pumped into the Zn concentrate filter where water is removed. Water is either sent to the Zn concentrate thickener or the filtrate water tank depending on recovery/concentrate grade. The Zn concentrate cake created by the filter is then sent to a screw conveyor which feeds the Zn concentrate bagging system where the concentrate is placed in a super sack and transported off site for sale. An SDS will accompany the bagged product to final delivery. Offtake is sold to a third party FOB mine warehouse and OSMI does not own the product once the bags are loaded for shipment. 3.4 Tailings Tailings from the Zn rougher scavenger flotation cells report to the tails filter feed tank or the tails thickener depending on the water content of the slurry. If additional water needs to be removed the tails will go to the tailings thickener. The tailings can be recirculated through the tailings thickener if need be before being sent on to the tailings filter feed tank(18,000 gallons). The tailings filter feed tank reports to the tailings filter presses. Here the water is squeezed out of the tailings and the cake tailings are allowed to drop down into two concrete floor bays,where a front-end loader will load the filter cake out for permanent placement in the Revenue or Atlas tailings storage facilities(TSFs). The tailings from the filer presses will be approximately 13- 20%moisture,which is appropriate for good compaction in either of the two permanent TSFs in the permit area. Tails will be compacted with a percentage of waste rock in accordance with OSMI's tailings management plan. The water removed from the tailings is recycled back into the process water circuit to be used in the mill process. Drawings 800-PI-003 and 800-MF-003 show a water treatment plant that discharges to a leach field,which is not going to be installed. The mill will start without a water Page 7 of 12