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None of the three shafts are located within a debris flow area. The only shaft that is located within an <br /> avalanche path is the 960 Shaft. The 960 Shaft is located near the top of an avalanche path and as such we <br /> do not anticipate buildup of snow in the area. The 6 feet diameter opening is expected to capture some <br /> snow during winter weather,however, snow entering the shaft is not expected to impact the mine as the <br /> shaft will be constructed on an angle and therefore,the snow cannot fall to the bottom. <br /> Air is usually supplied to working areas of the mine to provide an adequate volume of fresh air or to <br /> dilute or remove noxious gasses from blasting. This is done using electric powered fans that bring fresh <br /> air from the surface and distribute it using vent tubing. Most of the existing and future entries at the <br /> Revenue Mine are in some cases naturally ventilated but as described above, air currently exits the mine <br /> through the existing Hubb Reed raise bore and also will exit at the two new shafts (i.e.,the 960 and the <br /> Yellow Rose Shafts), once constructed. Fugitive emissions venting from the mine are included in the <br /> mine's Air Pollution Emission Notice,which is submitted to the Air Quality Control Commission. <br /> 3.4 Resue Mining Method <br /> Based on the orientation and width of the mineralization, review of historic mining, and available <br /> geotechnical information, a resue mining method is used to mine ore where waste rock serves as <br /> backfill as the stope is advanced in an overhead manner.This method is highly selective and allows for <br /> mining narrow widths down to 0.5 ft. <br /> Resue mining involves identifying a stope block having minimum approximate dimensions of <br /> approximately 500 to 1,000 ft along strike and up to 300 ft in height. Stope block widths vary <br /> according to mineralization. Typically, an off-ore access drift is developed on the footwall along the <br /> length of the stope. Two-compartment raises known as cribbed manways, are developed on each end <br /> of the stope from the level below providing access to any level of the stope. In the center of the <br /> stope a four-compartment service raise with a manway,two ore passes, and equipment slide is <br /> constructed as the primary access. Each raise provides utility access into the stope so that miners can <br /> pull water or air from either side of the stope or from the middle service raise. <br /> The bottom portion of the stope, approximately 25 ft in height, is left in a pillar (sill pillar), which is <br /> partially recoverable from the stope below. A 3.5 ft wide scram drift is developed along the length of <br /> the stope above the pillar. Finger raises with ore chutes at the access level connect the scram drift to the <br /> development access below and are used to remove ore material from the stopes. Once the scram and <br /> finger raises are established,upholes are drilled into the vein,both in ore and waste. Ore material is <br /> blasted first and then removed using slushers operating on a conveyor belt muck sheet to the finger raise <br /> for transportation to the mill. Prior to blasting the waste material,cribbed timbers are placed to raise the <br /> ore passes (similarly to the manway and service raises) to the next level. Waste material is then <br /> blasted and left in the stope as fill material for accessing the next level of the stope.Where necessary, <br /> additional waste can be drilled and blasted to fill the stope as mining progresses. <br /> 3.5 Explosives and Blasting <br /> Various types of explosives have been used at the Revenue Mine and depending on the location can <br /> consist of dynamite (stick power),ANFO (ammonium nitrate/fuel oil), or some combination of the two. <br /> Detonators are fuse primers,nonels, or electric blasting caps. All explosives will be stored underground at <br /> two locations—one in the Yellow Rose drift and another in near the Blue Lagoon on the Monongahela, as <br /> shown on Map C-la, C1-b and C-2. All explosives will be stored and handled according to Mine Safety <br /> and Health Administration(MSHA) and the Agency for Tobacco, Firearms and Explosives (ATFE) <br /> regulations. <br /> Revenue Mine <br /> Amendment 02 D-7 <br /> December 2021 <br />