2023-01-10_PERMIT FILE - M2023001 ‎(24)‎

• Permit No: M2023001
• IBM Index Class Name: Permit File
• Doc Date: 1/10/2023
• Doc Name Note: Attachment C - Slope Stability Report
• Doc Name: Application
• From: J-2 Contracting Company
• To: DRMS
• Email Name: PSH
• Email Name: JLE
• Media Type: D
• Archive: No

INTRODUCTION
J-2 Contracting Company proposes to mine the property located in the west half of
Section 3, Township 5 North, Range 65 West of the 6th Principal Meridian, in Weld
County, Colorado. The property is bounded by the private property on the west, the
Greeley-Weld County Airport on the north and east, private property on the east, and
East 8th Street on the south. The proposed mining operation will extract gravel reserves
from locations adjacent to man-made structures. The rules and regulations of the
Division of Reclamation, Mining, and Safety (DRMS) require that any mining within a
200-foot setback of a man-made structure show thorough engineering analysis that the
proposed mining will not cause damage to the structure. The accepted method of
demonstrating this is through a slope stability analysis. This report contains an overview
of the methodology used in the analysis of the mining slopes and their estimated affects
on all man-made structures. Recommendations regarding acceptable setbacks from
man-made structures have also been included.
OVERVIEW
The DRMS mining plan proposes that the property will be mined in 2 pits, and reclaimed
as a water storage reservoir. The mining will occur at 3H:1V slopes. A bench will be
constructed during mining to allow a slurry wall to be installed around the perimeter of
each pit. Clay soils will be placed above the bench to complete the reclamation of the
site. The reservoir (including both cells) will cover an estimated 54 surface acres when
full. The actual surface area of the cells will depend on the final configuration of the
reservoir after reclamation is complete.
GEOTECHNICAL DATA
Exploratory borings and monitoring wells were done on the site by Drilling Engineers.
Logs of the borings and monitoring well used to estimate the soil types and thicknesses
for this study are included in Appendix D. J&T Consulting, Inc. (JT) estimated soil
strength parameters based on the information from the boring and monitor well logs and
other stability analyses that have been performed on gravel mining operations along the
Front Range. Table 1, on the following page, represents a summary of the soil strength
parameters that were used in this stability analysis.
J-2 Contracting Company—Sunset Industrial Pit
In J&T Consulting, Inc. Slope Stability Analysis