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PERMFILE109423
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PERMFILE109423
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Entry Properties
Last modified
8/24/2016 10:02:10 PM
Creation date
11/24/2007 6:13:35 PM
Metadata
Fields
Template:
DRMS Permit Index
Permit No
C1982056
IBM Index Class Name
Permit File
Doc Date
12/11/2001
Section_Exhibit Name
EXHIBIT 07 SUBSIDENCE PREDICTIONS
Media Type
D
Archive
No
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• EXHIBIT 7 <br />SUBSIDENCE PREDICTIONS <br />MAIN ENTRIES <br />A five entry system of mains will be utilized for main mine access. <br />These entries will be on 80 ft. centers, and will be connected at 100 ft. <br />centers. The width of main entries wil] be 20 ft., giving the plan <br />configuration presented in Figure A. Main entry height will be kept <br />below 10 ft., which is the pillar height that has been used in pillar <br />strength calculations. <br />(a) Opening Span Stability <br />The Wadge Seam roof geology consists of interbedded sandstones, <br />siltstones and shales. The main roof units are depicted in <br />Figure B, which shows the average uniaxial compressive strength <br />and tensile strength for the predominant roof beam types. <br />• <br />The immediate roof beam (unit R1 in Figure B) is predominantly a <br />shale unit, which is approximately 1.5 ft. in thickness, and is <br />carbonaceous in places. This unit will require bolting to the main <br />roof beam (unit R2) to ensure stability, as it has a low uniaxial <br />compressive strength and a moderate tensile strength. <br />The main roof beam (unit R2 in Figure B) is predominantly sand- <br />stone with some minor siltstone and shale interbeds, and is <br />approximately 9 ft. thick. This is the main roof beam controlling <br />the opening span stability and it is moderately strong for coal <br />strata, with a uniaxial compressive strength of approximately <br />11,000 psi, and a tensile strength of approximatley 700 psi. It is <br />expected that this roof beam will remain stable with roof bolting to <br />an approved MSHA plan. <br />The upper roof beam (unit R4 in Figure B) is a sandstone unit, with <br />• some minor siltstone and shale interbeds, and is approximately <br />35 ft. in thickness. This unit is moderately strong for coal <br />Ex. 7-1 <br />
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