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REP37162
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REP37162
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Entry Properties
Last modified
8/25/2016 12:15:52 AM
Creation date
11/27/2007 7:42:05 AM
Metadata
Fields
Template:
DRMS Permit Index
Permit No
C1981041
IBM Index Class Name
Report
Doc Date
1/19/1995
Doc Name
ANNUAL SUBSIDENCE REPORT FN C-81-041
From
POWDERHORN COAL CO
To
DMG
Permit Index Doc Type
SUBSIDENCE REPORT
Media Type
D
Archive
No
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• Directly above the Hunter Canyon Formation is the Wasatch Formation. It <br />ranges from 280 ft. to 790 ft. of variegated clay shales of fluviatile and lacustrine <br />origin together with a few beds of sandstone. The bulk of the formation is made of <br />sandy and silty shales with sandstone constituting less than 3 percent of the rocks <br />in the formation. <br />Mining Swmmar_y <br />Currently, mining is concentrated in the 11th and 12th West Panels located in <br />Section 11 and 12 of T.11S., R.98W., 6PM. These panels were developed westward <br />from the No. 3 South Mains during the past year. At the present time secondary <br />mining is taking place in both panels and is projected to continue into early 1995. <br />Pillar sizes differ throughout the mine. The mains and submains which are <br />used to transport men into the mine and coal out of the mine are typically driven on <br />100 ft. x 100 ft. centers leaving a 81 ft. x 81 ft pillazs. The large pillazs in the mains <br />and submains are needed to handle the stress of the overlying stata for the life of <br />the mine. As a result of the large pillars, the extraction ratio can be as low 34%. <br />The pillars in the panels are usually smaller in an effort to increase extraction <br />and decrease cost. During the development of 11 West was driven with 60 ft. entry <br />• centers and 120 ft. crosscut centers and 12 West was driven with 70 ft. entry centers <br />and 120 ft. crosscut centers. The development extraction ratio for these panels was <br />approximately 42 and 39% respectively. During secondary mining these pillars are <br />cut to a size slightly larger that 15 ft. x 100 ft. increasing the extraction ratio in the <br />panels up to a maximum of 75 %. <br />Proiected Minim <br />During the 1995 year mining is projected to continue in the 11th and 12th <br />West Panels at the Roadside South Portal producing azound 1,800 tons per day. At <br />the Roadside North Portal, which resumed production on November 3, 1994, mining <br />will continue north in the No. 3 North Mains and west in the No. 2 West Mains <br />producing approximately 900 tons of coal mined per day. <br />Early in 1995 a continuous haulage section will be developed. This section will <br />either be North of the No. 5 East Mains in the Roadside South Portal or to the west <br />of the No. 3 North Mains at the Roadside North Portal. In either case, entries will <br />be developed in a chevron pattern on 70 ft x 70 ft. centers with no secondary mining. <br />With this configuration the continuous haulage sections aze expected to have an <br />extraction ratio azound 47% and produce 4,000 tons a day. <br />n <br />U <br />Page 2 <br />
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