2009-09-04_REVISION - M1987049

• Permit No: M1987049
• IBM Index Class Name: REVISION
• Doc Date: 9/4/2009
• Doc Name: Adequacy Review #5P
• From: DRMS
• To: Hart Environmental
• Type & Sequence: AM2
• Email Name: JLE
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF RECLAMATION, MINING AND SAFETY
Department of Natural Resources
1313 Sherman St., Room 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
COLORADO
D IV IS I ON OF
RECLAMATION
MINING
SAFETY
Bill Ritter, )r.
Governor
DATE:
TO:
FROM:
RE:
September 1, 2009
Jared Ebert
/
f
Allen Sorenson
Setbacks from Mining to Permanent Man-made Structures, Ready Mixed Concrete Company,
Bromley Lakes Pit, Permit Amendment AM-02, Permit No. M-1987-049
Harris D. Sherman
Executive Director
Ronald W. Cattany
Division Director
Natural Resource Trustee
The Division of Reclamation, Mining, and Safety engineering staff (DRMS) has reviewed item no. 32 from
Ready Mixed Concrete Company's August 19, 2009 adequacy response submittal. This item includes a
commitment to use a mining setback formula of 3:1 (horizontal:vertical) to protect structures for which
compensation agreements have not been secured. This setback formula is acceptable to DRMS, but must be
more precisely worded in order to be enforceable. Therefore the Applicant must provide a more concisely
worded permit commitment; the following wording is suggested:
The crest of all mined pit slopes will be maintained at all times at a horizontal distance from
permanent man-made structures not owned or controlled by the permittee or for which compensation
agreements described in Rule 6.4.19 have not been executed equal to at least three times vertical
height of the mined slope proximal to the structure.
The August 19, 2009 adequacy response points out that the requirements of Rule 6.4.19 apply when
permanent man-made structures will be adversely affected by the mining operations, and states that there is
no evidence that structures will be affected by the operations at the Bromley Lakes pits. To clarify, the
requirements of Rule 6.4.19 apply because structures will be adversely affected if there are pit slope failures
that undercut the structures, and there is no way to rule out the potential for such failures without some
evaluation based in the principles of geotechnical engineering. It is demonstrated in this case, through the
acceptance of the proposed 3:1 setback formula, that DRMS does not require detailed or rigorous analyses
unless such analyses are warranted.
c:\acs files\My Documents 4-19-06 thru\bromley lakes setback review 2.docx
Office of Office of
Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines