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<br />EXI~BIT C: MINING PLAN <br />(a) Period of Operation: Sierra Minerals Corporation (Sierra) desires to begin quarry <br />operations in July or August of 1999. Colorado Yule Marble Company (CYMC) operated the <br />quarry beginning in September of 1990 up until January of 1999 when the company failed. <br />Sierra has leased the quarry for 35 years, and holds an option to ]ease the quarry for and <br />additiona135 years. Reserves aze sufficient to support a mine 6fe well beyond the 70 yeazs <br />covered by the lease. Sierra intends to operate the mine for at least 20 years. This is the time <br />period envisioned for the term of this permit. <br />(b) Toasoil: The topsoil in the affected azea is very thin to non-existent and found in <br />small pockets on the generally rocky landscape. However, there is an azea of about'/. acre to the <br />south of the existing waste piles where salvage of topsoil appeazs feasible. Sierra will recover <br />these soils and create a topsoil stockpile at the southern boundary of the affected area before <br />waste is deposited in this area. Such topsoil piles will be placed to avoid contamination with <br />rock or other materials, out of traffic azeas, and not in areas where the material would be lost to <br />erosion. <br />(cl Overburden and Waste Rock: The quarry is an underground operation and will <br />remove material from areas already developed in the mazble seam underground. Additional <br />entries may be driven to the south of existing entries, but within the affected area, to allow <br />removal of material from newly developed areas. There are existing waste marble piles that <br />remain from prior operators. Most of the waste was generated from quarrying activities that <br />occurred between 1886 and 1941. Exhibit E -Mining Plan Map, with a background of an aerial <br />photo of the quarry site, cleazly shows the swface extent of these waste piles prior to 1990 with <br />the marble's characteristic brilliant white color. The background photograph was taken prior to <br />the operating activities of CYMC. CYMC's activities involved the construction of the private <br />access road, extension of existing waste piles a few tens of feet to the north, east, and south, <br />construction of access roads on the existing waste piles, and construction of stormwater control <br />featwes. Sierra anticipates no significant additions to these featwes, although portions of the <br />roads may be extended slightly or relocated to allow efficient placement of waste marble and the <br />marble waste piles will be extended to the east and south. <br />The operation will generate low volumes of waste mazble. Production rates anticipated <br />by Sierra aze between 4,000 and 16,000 short tons of dimension stone annually. Such operations <br />are expected to generate an equal tonnage of waste blocks, gravel, and saw cutting fines. The <br />fines will be small, minus 50 mesh, and will be high in moisture content (estimated higher than <br />50% moistwe) when placed upon the waste dumps. The materials will be blended in the dumps <br />to prevent the fines from causing sediment runoff, wind entrainment, and to effectively utilized <br />the waste area capacity by filling voids between the larger waste rocks. Some of the waste <br />materials may be removed from the site if suitable uses and markets can be developed for them, <br />ahhough initial plans only call for removal of dimension stone blocks from underground working <br />faces. Sierra will not dump fines on the waste piles until the effectiveness of the sediment <br />IS <br />