Laserfiche WebLink
Exhibit D <br />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 an in-pit crusher and <br />subsequently transported out of the pit and to the plant by covered conveyor. The crusher and conveyor <br />• will be extended as the mining face advances in each panel. Initially, as the first year production panel is <br />developed and the initial cut is advanced, rock will be hauled to a crusher temporarily located outside of <br />the pit. The crushed rock will be stockpiled temporarily adjacent to the pit until enough working area is <br />created in the pit to accommodate construction of a permanent conveyor corridor extending upward from <br />the pit to the top of the low wall and beyond to the primary stockpile associated with the plant. Drainage <br />management for this temporary situation is discussed later in Exhibit D under "Surface Water <br />Management Plan." It is anticipated that this period of initial development will take approximately 8 <br />months. Exhibit D-1 illustrates the approximate location of the temporary crusher and stockpile <br />associated with initial development of the pit, along with the permanent conveyor and conveyor <br />equipment. The exact locations of the crusher and conveyor equipment and temporary stockpile may be <br />modified as the first year mining plan is optimized. <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. The conveyor entering the first year mining block will <br />be extended along the length of succeeding initial Panel block cuts. It is anticipated that at a future date <br />the in-pit sump and truck/conveyor access entering the Year One block will be closed and reclaimed, and <br />the sump, equipment access ramp, and conveyor will be moved to a new pit entry point south-east of the <br />initial mining area. <br />Because of the gradually decreasing thickness of the limestone in an up-gradient direction, the area <br />• <br />1180-Mine Permit Exhibits (Jul.05.02)FINAL.dOc D-2 <br />July 8, 2002