PERMFILE56525

• Permit No: C1984065
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Doc Name: App. 4.3-1 Initial Geotech Study
• Section_Exhibit Name: APPENDIX 4.3-1 INITIAL GEOTECHNICAL STUDY LOGGING & TESTING EVALUATION
• Media Type: D
• Archive: No

24
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ENGINEERING DESIGN VALUES
RESULTS DISCUSSION
Upper Wheeler Roof. The roof materials appear to have a
great strength variation due to changes in rock type from one
hole to another. However, the strengths are relatively high on
the average, indicating a fairly strong rock mass above the
Upper Wheeler Seam. The slake potential is high but there is
little or no swell potential. The ratio of compressive strength
to tensile strength values is approximately 21:1 indicating
reasonably good laboratory procedures. The modulus ratio (Et/U)
is 150, indicating a lower strength rock than would be expected,
based on the uniaxial compressive test results.
Upper Wheeler Seam. The actual test results are about one-
half of the expected result of approximately 20 PIPa. The point
load test results indicate that the corresponding uniaxial com-
pressive strength(using a U:Ipratio of 24) should be about 19.7 MPa.
The triaxial test results, using a higher uniaxial compressive
strength, would give a lower initial friction angle and a higher
cohesion. Such results would be more in line with expected
results. The tensile strength results are also believed to be
low for the coal samples observed. The bulk density is approx-
imately as should be expected.
Interburden. The rock units making up this zone are moderate
in strength although the modulus ratio is only 176. The ratio
of uniaxial compression to tensile strength is 35:1 which is high
and indicative of a possibly low tensile test result. The tri-
axial results indicate a very low internal friction angle and
low cohesion. These results would probably be very different if
more tests were performed. The slaking potential is moderate,
but there is little or no potential for swelling.
Lower Wheeler Seam.
and tensile test results a
as are the cohesion values
friction angle values are
tests were performed, the
in line with the expected
indicate that the actual
order of 16 MPa, which is
coal.
The uniaxial compressive test results
re much lower than should be expected,
On the other hand, the internal
much too high. If greater numbers of
test results would very likely be more
results. The point load test values
compressive strength should be on the
more in line with experience for such
Lower Wheeler Floor. The floor materials have, in general,

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