2014-11-25_REVISION - M1979191 ‎(30)‎

• Permit No: M1979191
• IBM Index Class Name: REVISION
• Doc Date: 11/25/2014
• Doc Name: Geotechnical Stability Analysis
• From: GEI
• To: DRMS
• Type & Sequence: AM1
• Email Name: ECS
• Media Type: D
• Archive: No

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RECEIVED
� GEI
November 3, 2014 kfnV 2 5 2014
GEI Project Number 140521 -0 DIVISION OF RECLAMATION
MINING AND SAFETY
Eric Scott
-VColorado Division of Mining, Reclamation, and Safety
V 1313 Sherman St., Room 215
Denver, CO 80203
Re: -Geotechnical Stability Analysis for Martin Marietta Materials Three Bells Mine, M
1979 -191, Larimer County, Colorado
Dear Mr. Scott,
This letter addresses the Geotechnical Stability Exhibit for the Martin Marietta Materials,
Inc. (MMM) Three Bells Mine (M- 1979 -191) Reclamation Permit amendment, per Rule 6.5.
The geotechnical stability exhibit is required in the event of unretumed Structure Agreement
letters from owners of permanent structures within 200 feet of the mine boundary.
The Three Bells Mine is located in southeast quarter of Section 11, the southwest quarter of
the southwest quarter of Section 12, the east half of the northwest quarter of Section 13, and
the west half of the northeast quarter of Section 13 of Township 6 North, Range 68 West of
the 6th Principle Meridian.
Permanent man-made structures within 200 feet of the proposed excavation limits include:
East Larimer County Road 32E, parking lot, concrete path, various residential buildings,
various agricultural buildings, an oil well and pipeline, utility power lines, sewer lines,
municipal water station, weirs on the Cache la Poudre River, and bridges over the Cache la
Poudre River (see full list on page 2).
Geologic Strata and Mining Conditions
The Three Bells Mine is located adjacent to the Cache la Poudre River in Windsor,
Colorado. Mining will take place in the Three Bells Ditullio property in five phases. Phases
1, 3, and 4 will be lined with a compacted clay liner (CCL). Phase 2 will become an unlined
pond. Phase 4 will be partially backfilled and Phase 5 will be completely backfilled.
Veldman is currently undergoing reclamation with an approximate completion November
2014.
Boring data gathered from boreholes advanced by others in 2013, in addition to observations
made within the mined pits, indicates that overburden is located at the surface of the mine,
below which is a layer of pit run (sand and gravel), overlaying bedrock. Overburden and pit
run have variable depths, depending on locations in the mine and the mining phase. The
www.geiconsultants.com GEI Consultants, Inc.
2625 Redwing Rd. Suite 370, Fort Collins, CO 80526
970.224.7343 fax: [phone]