2023-08-31_ENFORCEMENT - M1982121

• Permit No: M1982121
• IBM Index Class Name: Enforcement
• Doc Date: 8/31/2023
• Doc Name: Rock Failure Analysis and Stability Report
• From: RMR Aggregates, Inc.
• To: DRMS
• Email Name: ACY
• Email Name: THM
• Media Type: D
• Archive: No

K1L D UFF RMR Aggregates, Inc.
U N ❑ E R G R O U N ❑ Rock Failure Analyses and Stabilization Report
E NGIN E E R I N G,INC. Mid Continent Limestone Ouarry
site reconnaissance, two slope materials were identified: limestone headwall and Limestone Scree/
Blast pile. A mean value was assigned for each property with a normal distribution of standard
deviation. Similar to the slope stability analyses, input values for normal restitution, tangential
restitution, dynamic friction and rolling friction were initially derived from desktop literature review.
The values were verified under a back analysis on the west wall along trend of the January 2023
ground event. Input values were revised until the rockfall runout and energy resembled that of the
2023 ground event, correlated to topographic data of the rockfall debris field. Summary of slope
input parameters is provided in Table 3.
Table 3. Rockfall Simulation Input Parameters
Normal Tangential
Material Restitution Restitution Dynamic Rolling
Friction Friction
(Rn) (Rt)
Mean 0.32 0.71 0.55 0.15
Leadville
Limestone Standard
0.04 0.04 0.04 0.02
Deviation
Mean 0.32 0.71 0.55 0.30
Interbed
Material Standard
0.04 0.04 0.04 0.04
Deviation
Damping was disabled for viscoplastic and forest & vegetation. Slope roughness parameters were set
to 0 degrees because roughness is already accounted for by the detailed slope geometry used in the
model. Three rock types were used with increasing size and mass to mimic the January ground event.
The rigid body method was used to allow definition of rock size, mass and shape. The 1) Small (2022
Ibm), 2) Medium (20,227 Ibm), and 3) Large (93,642 Ibm) blocks were assigned square, pentagon and
rhombus shapes to simulate the ground event blocks observed in the debris pile.
Computational modeling was completed with a linear seeder point at the top of the upper limestone
bed with a minimum of 3,000 rocks simulated. A crest loss of the overhanging limestone bed was
induced to remove that geometry at point of rockfall initiation to maximize the translational velocity.
Detailed results on the distribution of bounce height, velocity, and impact forces for each run were
obtained by locating data collectors along the slopes. Those results were used to evaluate
appropriate berm height, setback from the slope toe, and determined total energy impacting the
berm.
5.2. ROCKFALL MITIGATION RECOMMENDATIONS
Based on the results of the rockfall modeling along the West face and multiple East face transects,
the following recommendations and descriptions of rockfall treatments are provided below.
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