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Description of Mining Plan <br />Mining equipment for the amended area (rotomills, front- end loaders, tractors <br />with bottom-dump trailers, etc.) will remain the same as in the existing area. The <br />rotomills will "plane" the gypsum in successive layers of approximately 6 inches, as in <br />the current mining operation. Each pass of the machine will cut the rock to a width of 10 <br />or 12 feet depending on the machine utilized. The mined rock will be deposited in a <br />windrow behind the machine and loaded into trucks if sizing is suitable for direct <br />shipment to the plant at that point. Variations in weathering and rock stratification will at <br />times cause the gypsum to breakout as "oversize". This material will be re-sized with a <br />portable screening plant before it is hauled to the wallboard plant. Waste rock material <br />will be loaded into an articulated haul truck. Depending on the stage of the operation -the <br />non-gypsum rock will be hauled to an initial valley fill area, used for road widening, or <br />used for reclamation backfill as described in more detail below. <br />The current method of cutting benches to a height of 40 feet will remain the same <br />as in the existing operation. However, the mining sequence and reclamation method will <br />be changed. The mining sequence will be divided into distinct stages. During each <br />mining stage the rotomills will lower the surface by successive bench heights. In each <br />stage, the active mining plateau will gradually widen to the bottom contact of gypsum <br />and underlying clastic sediments <br />The mining sequence will utilize a concept of sequential backfilling and <br />concurrent reclamation. Based on exploration drill hole information, the ore body has <br />been divided into five stages of development noted as Stages A through E on the mine <br />plan map (Exhibit C-1). Mining will progress down dip in the five intermediate stages <br />defined by mass balance ratios (depleted ore zones vs. non-gypsum material). After ore is <br />depleted from each zone, waste rock from the zone below it will be backfilled in the <br />depleted area and re-sloped at a 2 %: 1 ratio. A CD digital terrain model depicting this <br />staged mining activity in animated form is on file with the Eagle County Planning <br />Department. <br />Non-gypsum rock is inter-bedded throughout the gypsum in the form of clastic <br />sediments. This rock is estimated to comprise 26% of the total tonnage contained in the <br />deposit. Exploration drilling defined a southwesterly dip of approximately 40 degrees in <br />the ore body which lends an exact fit to the sequentiaUdown dip mining approach. The <br />structure of the orebody is very similar to that of the existing operation - a synclinorium <br />within the northern limb of the Eagle River Evaporate Formation anticline. <br />Some adjustments in the number of mining stages may be necessary as mining <br />progresses depending upon the actual depth of gypsum and volume of non-gypsum rock <br />encountered during operations. <br />When road access to the top of the orebody is complete, topsoil and vegetation <br />will be cleared from the initial mining area (Stage A). The gypsum rock essentially <br />outcrops at the surface so the rotomill will begin extracting ore and flattening the initial <br />5 <br />