2007-12-18_PERMIT FILE - M2009053

• Permit No: M2009053
• IBM Index Class Name: PERMIT FILE
• Doc Date: 12/18/2007
• Doc Name: Blasting Vibration Control Plan
• From: Merritt LS, L.L.C.
• To: DRMS
• 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]
DATE: December 19, 2007 11-?
TO: Kate Pickford
i
FROM: Allen Sorenson
RE. Be? view of Blasting Vlbration Control Plan, Robins Construction, L.L.L.P.,
Robins Rock Pit, File No. M-2007-080
COLORADO
DIVISION OF
RECLAMATION
MINING
SAFETY
Bill Ritter, Jr.
Governor
Harris D. Sherman
Executive Director
Ronald W. Cattany
Division Director
Natural Resource Trustee
The Division of Reclamation, Mining, and Safety (DRMS) minerals program engineering section has
reviewed the blasting report for the proposed Robins Rock Pit, prepared by Merritt LS, L.L.C. and dated
December 17, 2007 (Merritt Report). The Merritt Report provides a good structure and template for the
regulation of blasting at the proposed Robins Rock Pit. However, a number of details must be sufficiently
addressed prior to DRMS consideration to approve or deny the permit application.
1. The maximum charge weight per delay criterion suggested in the Merritt Report was published in
the 1960s, and has been superseded by the Scaled Distance Equation, which is based on
investigations conducted by the U.S. Bureau of Mines in the 1980s. The Scaled Distance Equation
is:
W = (D/Ds)2
Where W = the maximum charge weight per 8 millisecond delay period, in lbs.
D = the distance from the blast location to potentially affected structures, in feet
Ds = the minimum scaled distances, which by definition are:
for D = 0 to 300 ft., Ds = 50
for D = 301 to 5000 ft., Ds = 55
and for D = 5001 ft. and beyond, Ds = 65
The DRMS will require that all blasting at the proposed quarry be conducted in accordance with the
Scaled Distance Equation. The following table illustrates how the Scaled Distance Equation is
used, and that anomalies occur at the regulatory Ds change distances of 301 and 5001 feet. These
anomalies will not affect operations at the proposed Robins Pit because as explained in item no. 2
below, the location of the Haberkon House 0.8 miles from the blast site is the controlling factor for
blasting.
DISTANCE - FT. MINIMUM Ds MAX. CHARGE WT./DELAY, LBS.
100 50 4.0
300 50 36.0
310 55 31.8
330 55 36.0
500 55 82.6
Office of Office of
Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines