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Albert Frei and Sons, Inc. September 24, 2018 <br /> Hatchery Pit <br /> Permit # M-2014-043 <br /> TECHNICAL REVISION 01 EXPLANATION <br /> This Technical Revision for Hatchery involves changing 3 parts of <br /> the permit for mining in Stage 2 and a minor revision to the <br /> reclamation plan in the northwest lake area . <br /> Stage 2 revisions . <br /> Original plan called for mining Stage 2 in two passes, first <br /> creating a level that is 17 ft above the underlaying shale at an <br /> elevation of approximately 50721 . Then installing a slurry wall <br /> around the perimeter of the mined area on that level and finally <br /> mining out the material left in the lined area. The slurry wall <br /> served 2 purposes one was to reduce the need to de-water Stage 2 <br /> and then as a barrier to keep water out of the area during <br /> placement of inert fill . As the mine has developed, it has been <br /> found that it is economically feasible to de-water and mine the <br /> entire depth of Stage 2 instead of what was originally proposed. <br /> These changes are based on the actual operating procedure worked <br /> out as the mine has developed and make the most economic sense <br /> due to the nature of the gravel deposit . <br /> The first change is to the method of mining in Stage 2 . In this <br /> change instead of completing Stage 1 first and doing a double <br /> pass thru Stage 2 the plan is mine a 250 foot wide trench from <br /> the Plant Site east to the mining setback, following the shale <br /> that is near the surface at the Plant Site area . This will leave <br /> a working face running east-west along the north side of Stage 2 . <br /> Once the trench is complete mining will resume in Stage 1 and <br /> continue till all material is removed. <br /> A dewatering pump will be placed in the northwest part of Stage 2 <br /> and the water will be channeled across the shale and discharged <br /> into the old lake for return to the ground water system. All <br /> permits are in place to accomplish this . A Well Permit (#82163F, <br /> issued 6/8/2018) and Substitute Water Supply Plan (expires <br /> 9/30/2019) are in place for the use of water at the mine . <br /> The second change is to removed the planned Slurry Wall from <br /> Stage 2 and instead place a compacted fill liner in the lower 15 <br /> feet of the excavation. The top will be placed at what is the <br /> current water table elevation of 5072 , msl . A french drain <br /> system will be built on top of the liner along the up gradient <br /> sides of Stage 2 to channel ground water around the filled area <br /> and to maintain historic groundwater elevations on the up <br /> gradient sides . The drain will minimize the impact the fill will <br /> have on the surrounding ground water table . The liner will be <br /> 1 <br />