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fine- grained siliciclastic sediments (e.g. mudstone) due to shallower, higher energy water depths <br />— resulting in purer lime muds than found in correlative strata in the surrounding regions of <br />Huerfano, Fremont, and El Paso counties. <br />4. Existing overburden on the proposed Rio Grande surface mine lands ranges from 0.0 m to 10.0 m <br />[yielding a +0.8:1 overburden ratio] greatly reducing the need for extensive blasting and removal <br />of non - economic materials. "Overburden" includes the shale and unconsolidated materials above <br />the mineable Fort Hays unit. Unconsolidated materials consists of an A soil horizon, an A -C <br />subsoil horizon, and other materials above the shale. <br />MINING <br />Erosion and sedimentation control structures will be placed in watersheds prior to other mining and <br />reclamation activities. Topsoil and subsoil salvage operations will commence after water control and <br />treatment structures have been completed. The extraction of the Fort Hays Limestone will be conducted <br />by an open pit operation. The maximum thickness of the unit exceeds 35 feet (refer to Exhibit C -4) with <br />the actual thickness being variable due to depositional character, quality, and erosion. Mining activities <br />will be conducted with two shifts per day based on an 8 -hour shift period with a six -day workweek. <br />Surface mining operations will be limited to 10 hours per day between 6:00am and 9:00pm, and topsoil, <br />subsoil, other unconsolidated materials, and shale removal will be limited to 8 hours per day between <br />7:00am and 7:00pm. Mining operations will use standard methods and equipment commonly used in <br />limestone quarries. Mobile equipment will be used, such as (or the equivalent of) Caterpillar 623 scrapers, <br />Caterpillar 988 front -end loaders, and 44 -ton rock trucks. <br />Limestone and sandstone required for the cement plant will be reduced in size by a mobile in -pit crusher <br />and subsequently transported out of the pit and to the plant by covered conveyor. The crusher and <br />conveyor will be extended as the mining face advances in each panel. <br />Initially. as the first year production panel is developed and the initial cut is advanced, rock will be hauled <br />• <br />adjacent to the pit until enough working area is created in the pit to accommodate construction of a <br />permanent conveyor corridor extending upward from the pit to the top of the low wall and beyond to the <br />primary stockpile associated with the plant. Drainage management for this temporar <br />- -. r <br />TR 4 with Markup <br />April 26, 2013 <br />initial development will take approximately 8 months. Exhibit D I illustrates the approximate location of <br />the temporary crusher and stockpile associated with initial develop-merit o <br />and temporary stockpile may be modified as the first year mining plan is optimized. <br />The initial mining work described in the initial permit application and shown in Exhibit D -1 is complete. <br />The areas Y1 through Y3 are mined and mining has moved into Y4. The southeast boundary line of panel <br />1 is slightly realigned. <br />Mining will be conducted in a series of panels, oriented up the dip of the limestone. Each panel will be <br />approximately 1,400 -feet wide, with its base approximately parallel to the strike of the limestone. The <br />upslope length varies. Panel One, for the first five years of operation, will extend approximately 2,600 <br />feet upslope. Panel Two, oriented parallel to Panel One, will be operated for the following ten years. <br />Panel Three, oriented parallel to Panel Two, will be mined following the completion of Panel Two. This <br />pattern will be repeated over the life of the mine. Stationary and/or mobile con ve fors will extend to the <br />southeast as each panel is opened. iEithin each panel, the conveyor will he extended to the east or ~rest <br />D -2 <br />