2024-02-02_REVISION - M1982121 ‎(6)‎

• 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

KILDUFF RMR Aggregates, Inc.
UN DER 3 R O U V z Rock Failure Analyses and Stabilization Report
E IJ GI NE ER IN G. INC. Mid Continent Limestone Quarry
5. ROCKFALL
5.1. ROCKFALL MODELING
Rockfall modeling was performed on three transects along the East face that are representative of
the varying geologic and topographic conditions (Figure 2a).The three slope geometries were created
from LiDAR data provided by RMRA. Modeling was performed using the computer program Rockfall
v.8.004 by RocScience that simulates the bounce paths of rock blocks down a slope,and calculates
block velocities, end points and kinetic energies at user specified points along the slope. The rockfall
simulation uses coefficient of restitution (both normal and tangential) parameters to model the loss
of kinetic energy between the rockfall block and ground surface at the paint of impact. Based on the
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) tRtl
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 Iinear 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
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