2023-10-31_REVISION - M1973021 ‎(15)‎

• Permit No: M1973021
• IBM Index Class Name: Revision
• Doc Date: 10/31/2023
• Doc Name Note: Attachment A - Rule 6.5 Geotech Stability Exhibit - Intro and Table of Contents
• Doc Name: Request for Technical Revision
• From: Holcim - WCR, Inc.
• To: DRMS
• Type & Sequence: TR9
• Media Type: D
• Archive: No

Geotechnical Stability Exhibit ���
Engineering Evaluation of Highwall Design for the South Quarry of the Morrison Quarry
Contents
1 Introduction ........................................................................................................................3
1.1 Purpose and Scope...................................................................................................3
1.2 Site Description .........................................................................................................3
2 Geologic Conditions ...........................................................................................................6
2.1 General Geology.......................................................................................................6
2.2 Morrison Quarry Geology ..........................................................................................7
2.3 Rock Types ...............................................................................................................7
3 Field Evaluations................................................................................................................8
3.1 Annual Quarry Inspections ........................................................................................8
3.2 2022 Geotechnical Borings........................................................................................8
3.2.1 Geophysical Evaluations................................................................................9
4 Laboratory Testing ...........................................................................................................10
4.1 Previous Testing......................................................................................................10
4.1.1 Historic Strength Testing..............................................................................10
4.2 Recent Testing ........................................................................................................12
4.2.1 Recent Strength Testing ..............................................................................12
4.2.2 Aggregate Property Testing .........................................................................15
4.2.3 Petrographic Analysis ..................................................................................16
5 Design Methodology.........................................................................................................18
5.1 3-D Geologic Model.................................................................................................18
5.2 Bench Stability.........................................................................................................18
5.2.1 Hoek-Brown Parameters..............................................................................18
5.2.2 Kinematic Analyses......................................................................................24
5.2.3 Slope Stability Analyses...............................................................................26
6 Quarry Geometry Recommendations ...............................................................................29
6.1 Kinematic Stability Results ......................................................................................29
6.2 Slope Stability Results.............................................................................................29
7 Limitations........................................................................................................................30
8 References.......................................................................................................................31
Figures
Figure 1: Project location of the Morrison Quarry .......................................................................4
Figure 2: Approximate extents of mining cells within Morrison Quarry........................................4
Figure 3: Geologic map of project area ......................................................................................7
Figure 4: Suggested Value of D based on excavation method (Hoek, 2000)............................20
May 2023 1 i