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1994-01-01_PERMIT FILE - C1981017 (5)
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1994-01-01_PERMIT FILE - C1981017 (5)
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Last modified
7/7/2022 8:43:05 AM
Creation date
6/7/2012 10:39:25 AM
Metadata
Fields
Template:
DRMS Permit Index
Permit No
C1981017
IBM Index Class Name
Permit File
Doc Date
1/1/1994
Doc Name
Road Reclamation at Entire Coal Basin Complex
Media Type
D
Archive
No
Tags
DRMS Re-OCR
Description:
Signifies Re-OCR Process Performed
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2. Discussion of Area Geology and Soil Types <br />The Coal Basin Mines are located in a northwest trending, <br />elliptical anticline of approximately 26 miles in size. The western <br />edge of the anticline is rimmed by outcrops of the Williams Fork <br />Formation of the Mesa Verde, which contains the coal seams. <br />The enclosed Figure 1 shows the strata found from the portal areas <br />to the prep plant area located at the low point of the property. <br />All the mines at Coal Basin are located in the "B" Seam except for <br />Mine #2 which was in the Middle Seam or Dutch Creek Seam. All <br />significant roads are located in strata from the "B" Seam to the <br />Mancos Shale. Exhibit 1 also shows the plan view of the roads and <br />the type of strata in which they were constructed. <br />Located immediately below the "B" Seam is the Rollins Sandstone, <br />which is a buff to white, relatively massive sandstone usually seen <br />in large tabular sets. On steep slopes, a near vertical ledge can <br />be traced around the terrain. Its total thickness is from 80 to 130 <br />feet although it is split in the middle by a mudstone from 5 to 15 <br />feet in thickness. The upper 5 to 20 feet of the sandstone are <br />bleached white at the outcrop. I t is feldspathic to quartz i t i c ; its <br />grain size varies from fine to medium - grained and it contains some <br />chert and coalified plant material. When broken for road <br />construction, the resulting material is angular, coarse and <br />resistant to weathering. Residual clays and loam do not form <br />readily from this material. Another minor sandstone, the Cozette, <br />is located approximately 900 feet below the Rollins. It is gray, <br />fine to very fine grained, thin bedded and feldspathic to lithic. <br />It is also resistant to weathering, but to a lesser degree than the <br />Rollins Sandstone. <br />Below the Cozette Sandstone is a thickness of over 4000 feet of <br />Mancos Shale, which accounts for all of the remaining road cuts to <br />the prep plant and the vast majority of the road cuts overall. The <br />strata consists of shales, mudstones, siltstones, and a few thin <br />sandstones. Units are light to dark grey, massive to thinly <br />laminated to sha l y and contain very fine feldspathic sand which can <br />be locally micaceous. The Mancos Shale covers an extensive area in <br />Colorado; however, in Coal Basin, the sedimentary strata has domed <br />over an igneous intrusion. As stated in the permit, the intrusion <br />was probably a laccolith. Although no main igneous mass is seen on <br />the surface, Tertiary age dacite dikes and sills have been traced <br />on the surface, in drilling and in the mine workings themselves. <br />Most have been identified south of the Coal Creek drainage. T h i s <br />past igneous activity is very important because, in many areas, it <br />2 <br />
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