2021-07-19_REVISION - M1987026 - Laserfiche WebLink

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Activities occurring on the site consist of stripping and stockpiling topsoil for later use in reclamation, stripping the overburden down to the top of the obsidian deposit in the area to be mined, drilling and blasting the obsidian, and moving and stockpiling the product for offsite sale and use. The deposit is "pure" enough that there is no waste or reject material produced during the mining and handling of the obsidian. The material is also sufficiently durable and competent to remain as a steep wall in the long- term. The overburden that is stripped is not considered a product. It is not being processed, sold, or exported. It has been used to build the operations pad and earthen stormwater controls. The overburden lying above the obsidian to be mined is stripped, and the margins of this stripped area are graded to a stable slope (about 2H:1V). All "excess" overburden that is stripped is hauled to an onsite location,where it is shaped, topsoiled and revegetated. The topsoil that is stripped during the operation is stockpiled and seeded to protect it for use in later reclamation. Wherever possible, the operator performs reclamation concurrent to the mining operation. Weed control and stormwater control are currently carried out. Equipment used on the site includes bulldozer, wheeled loader,tracked drill, haul truck, and conveyor/ stacker. All explosives,fuel, lubricants, and other materials used onsite are either delivered for use that day or stored properly, i.e., in clearly labeled areas away from other site activities, and secured, and with sufficient containment, as needed. These practices will be continued under the 112c permit mining plan. Proposed Mining Plan under Planned Expansion—Phase I The proposed mining plan in the expanded area will generally follow the steps already in use in the existing plan, with a few additional significant details. Recent drilling has helped greatly in defining a larger area of extent and depth of the obsidian deposit currently being developed. The new plan will begin with further defining the areal extent of the mineable obsidian deposit. An additional deposit to the north will be further defined, and the future mining will be another phase. When the economically viable extent of the deposit has been defined, the operator will strip the topsoil and slope the overburden within the delineated mining area, rather than the method of incremental stripping presently employed. This will be for purposes of facilitating more timely reclamation and revegetation of the mining-related disturbance. Because of the acreage of the larger quarry and the average depth of overburden to remove, there will be a significant volume of overburden to permanently place on the site. In addition, there will be a larger amount of sloped (disturbed) land above the highwall of the larger pit. The plan to perform all the stripping, stockpiling and shaping early in the process will allow the operator to begin the surface reclamation on the emplaced overburden and new slopes above the highwall, beginning at the initiation of expanded operations. The proposed Phase I expansion of the quarry and staging and stockpile areas will grow from their present locations to adjacent, undisturbed areas. The extraction area (highwall and pit floor) will generally grow to the north and east; the staging and stockpile areas will grow to the south and west. Most of the access road will remain in its present location except where slight realignment is required to accommodate the additional drainage and stormwater controls. (Please see the Exhibit C map showing the locations of these features.) The new slopes above the expanded quarry highwall resulting from stripping the overburden will initially be graded to not exceed 2H:1V. Some of the stripped overburden will be used to build the expanded