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RECLAMATION - BENCHES <br /> thus increasing the erratic tendencies. The shale is fine grained and soft. <br /> On exposure it breaks into small shaley fragments, contributing great <br /> quantities of light brown to gray colored mud and silt during periods of high <br /> runoff. <br /> • The shales of the overlying Mesaverde formation, including the 1,000' <br /> "tongue" of Mancos shale, are also highly erodable, and erratic. The <br /> sandstone members exhibit greater competence, and are distinguishable <br /> as nearly vertical cliffs. <br /> • Members of the Mesaverde Group are characterized by the following <br /> erosional tendencies. <br /> • Cozette Sandstone: forms ledges and waterfalls at outcrop. <br /> • Mancos Shale: fine grained, soft, and erodes easily in the form of mud <br /> and silt. <br /> • Rollins Sandstone: forms a nearly vertical cliff at outcrop, along the basin <br /> and erodes in large blocks and boulders. <br /> • Bowie Shale: commonly exposed in cliff faces around the basin. The unit is <br /> well exposed, so weathering and erosion is intense. <br /> • Middle Sandstone: Occurs as a nearly vertical cliff face at outcrop around <br /> the basin. It erodes in large blocks and boulders. <br /> • Paonia Shale: Exhibits the same erosional tendency of the other shales. <br /> • Upper Sandstone: Occurs as a nearly vertical cliff face at outcrop around <br /> the basin. Like the other Rollins and Middle members, it also erodes in <br /> larger blocks and boulders. <br /> THE BENCHES <br /> As indicated In the Geo-Hydro Study: <br /> = All mine benches were constructed in a similar way: a high cut was <br /> excavated above the coal seam outcrop. The elevation of the cut toe <br /> coincides approximately with the bottom of the coal seam and with the <br /> elevation of the mine bench. The excavated material was deposited in one <br /> or more fills. <br /> 3 <br />