REP28166

• Permit No: C1981047
• IBM Index Class Name: Report
• Doc Name: INITIAL INSPECTION AND RECOMMENDATIONS MINE BENCH STABILIZATION
• Permit Index Doc Type: STABILITY REPORT
• Media Type: D
• Archive: No

Mine Bench Stabilization
November 9, 1984
• Page 3
3. Density testing frequency for initial fill operations
should be a minimum of two passing tests per lift, with the
frequency not to exceed one test per thousand cubic yards.
After fill operations proceed with consistent results and
fill elevations reach the previous ground surface, test
frequency of one test per two thousand yards is
recommended.
4. In order to properly tie the bench fill and existing slope,
it is recommended that a 10-foot bench be utilized at 10-
foot elevation intervals. The methodology is illustrated
in Figure 1.
5. In order to adequately transition between the bench fill
material and the select material within the foundation
excavation, special placement operations should be utilized
between station 2 + 00 and 1 + 63. Figure 2 represents the
configuration recommended.
6. During the performance of the density tests, should any
test fail in moisture or density requirement, this area
must be removed or reworked, recompacted and retested, such
that passing test results are achieved. Further, all tests
which fail should have documentation to the conditions
• which were performed following the failing tests and either
the material should be removed, or the records should show
a passing test in this area before any further fill
operations continue.
7. The tension crack locations and widths at the top of the
slope should be monitored on an hourly basis during the toe
excavation. If the rate of movement increases beyond past
experience, the toe should be, if possible, stabilized by
rapid placement of fill at the toe area. If it is felt
that this operation could not be conducted in a sufficient
amount of time, then notification to mine personnel to
evacuate the area on the top of the slope and at the bottom
of the slope to ensure safety should be implemented. If
the rapid placement of fill at the toe area is utilized,
operations can then be carefully made to replace the fill
once the slide has been stabilized.
~ 8. Once the limits of excavation have been achieved within the
toe excavation area, special placement operations should be
I utilized in the event that excess water is encountered in
the excavation. This method should be utilized if the
initial soil fill lift cannot be sufficiently compacted to
I provide passing test results due to excess moisture
conditions. If this condition occurs, the 8-inch minus
• rip-rap material should be placed as the first lift to
provide a stable working base for previous fill operations.
I