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2024-02-02_REVISION - M1982121 (6)
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2024-02-02_REVISION - M1982121 (6)
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Last modified
2/2/2024 4:43:17 PM
Creation date
2/2/2024 4:30:29 PM
Metadata
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Template:
DRMS Permit Index
Permit No
M1982121
IBM Index Class Name
Revision
Doc Date
2/2/2024
Doc Name
Adequacy Review Response
From
RMR Aggregates, Inc
To
DRMS
Type & Sequence
TR6
Email Name
ACY
Media Type
D
Archive
No
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KILDUFF4L RMR Aggregates, Inc. <br /> N _, E P l; ,1 _ Rock Failure Analyses and Stabilization Report <br /> d L =k Mid Continent Limestone Quarry <br /> Table S. Typical Mine Design Criteria for Slopes <br /> Wesseloo &Read, 20099 <br /> Consequence of Failure <br /> Slope Scale <br /> Low Medium High <br /> Bench FOS ? 1.1 <br /> Inter-Ramp FOS? 1,15-1.2 FOS? 1.2 FOS? 1.2-1,3 <br /> Overall FOS? 1.2-1.3 FOS? 1.3 FOS? 1.3-1.5 <br /> For the RMR Aggregate site, the failure path of the slope could impact quarry facilities on the bench, <br /> so the consequence of failure from medium to high was evaluated.This correlates with the ❑RMS <br /> recommendations reproduced in Table 4, corroborating a FOS of 1.5 was considered as the minimum <br /> acceptable FOS. <br /> Based ❑n the slope stability results for the west wall,the massive limestone is stable for a variety of <br /> bench slope geometries.Slope stability static and pseudostatic results for the west face based on the <br /> above conditions are summarized in Table 6. <br /> Table 6.Summary of Factor of safety for varying bench slope <br /> geometries <br /> Bench Slope Geometry Static Factor of Seismic Factor of <br /> (Horizontal:Vertical)l Safety (long-term) Safety (long-term) <br /> 1:1 2.74 2.38 <br /> 1.4:1 2.28 1.82 <br /> 1.67:1 3.43 3.03 <br /> 1. Max bench height of 30 feet <br /> The higher than anticipated factor of safety for the 1:1 geometry is largely a result of the model <br /> considering the massive limestone as a monolithic mass.A tension crack was induced as a release <br /> plane because that joint is a persistent joint set across the site likely a result of structural folding of <br /> the limestone. However, no interbed,joint or zone of weakness has been encountered, either in <br /> geologic mapping or mining operations, in the massive limestone providing a release plane.To <br /> evaluate the potential for an unknown zone of weakness within the massive limestone,the long-term <br /> steady state stability analysis of the west face was run again with a reduced cohesion of 1,500 psf <br /> (70%reduction from the empirical value)to mimic a loss of internal granular cohesion or strength. <br /> 9 Wesseloo,J.and Read,J.(2009).Chapter 9-Acceptance Criteria.In:Guidelines for open Pit Slope Design,J.Read and P. <br /> Stacey(eds),pp 221-236.CIRSO publishing.496p. <br /> Page 12 <br /> 53516-STREET,SUITE 620 1 DENVER,CO 80202 1 (303)732-3692 1 WWW.KILDUFFUNDERGROUND.COM <br />
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