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and the highwall will eventually be filled in from the ongoing processing. It is, however, under- <br />stood that the highwall must be bonded for the worst case, which is the current condition. <br />This current highwall at the infiltration pond will require 12,000 cubic yards to backfill to the ac- <br />cepted post -mine land use of rangeland. A swale may be left in the landscape but no slope will be <br />steeper than 4H:1 V. <br />Section 5.0 Topsoil Removal and Stockpiling <br />Much of the site was disturbed over a century ago and no topsoil was salvaged from this operation. <br />Since the operation was permitted in 1984, two topsoil piles have been created. One is located <br />north of the mine access road in the center of the property. This is called Topsoil Stockpile #1 and <br />is approximately 0.33 acres and 12 feet high with slopes of 2.5H:1 V. This pile contains approxi- <br />mately 4200 cubic yards. Topsoil Stockpile #2 is located east of the living trailers and is 0.34 acres <br />in size with an average height of 9 feet. This pile contains approximately 4900 cubic yards. There- <br />fore, the total amount of topsoil stockpiled is 9100 cubic yards. <br />A fill pile is located above and south of the Plant Infiltration Pond, which contains approximately <br />16,000 cubic yards in an area of 0.53 acres. This fill will be used to backfill the highwall at the <br />southern end of the infiltration pond. <br />As seen from Map C -1, additional topsoil is available from some undisturbed portions of the area <br />to be mined. These areas will have approximately 6 -8 inches of usable topsoil. This soil will be <br />carefully stripped and added to Stockpiles #1 and #2. As mined out pits are backfilled and <br />regraded, topsoil will be replaced on these areas to a depth of 6 inches. <br />In addition, fines from the gold processing and gravel processing plants will be captured and stock- <br />piled for use as a substitute subsoil to be placed below the available topsoil. This will provide <br />greater root depth capability and water retention in the soil. It is estimated that normal mining oper- <br />ations will produce approximately 4000 cubic yards per year of this material. The Substitute Sub- <br />soil Stockpile is shown on Map C -2. <br />Gloria Z Mine 2013 Amendment 13 <br />