2020-12-04_PERMIT FILE - M2009053

• Permit No: M2009053
• IBM Index Class Name: Permit File
• Doc Date: 12/4/2020
• Doc Name: Adequacy Review Response
• From: Summit Engineering Co.
• To: DRMS
• Email Name: LJW
• Media Type: D
• Archive: No

SUMMIT ENGINEERING C 0 1 ENGINEERS & LAND SURVEYORS
Mail: P.O. Box 1897 Alamosa, CO 81101 P: 719-589-6147 E: [e-mail]
STATE OF COLOMDO
DIVISION OF RECLAMATION,MINING AND SAFETY
Department of Natural Resources
1313 Sherman St.,Room 215
Denver,Colorado 80203 C O L O R A D O
o I V I s 1 o N o r
Phone:[phone] RECLAMATION
FAX:[phone] MINING
DATE: December 19,2007,/� SAFETY
Bill Ritter,(,.
TO: Kate Pickford G—or
Hams D.5he—
FROM: Allen Sorenson✓ Fcecut—Daeaor
It— W.Canany
Division Director
RE: Review of 81astin Vibration Control Plan,Robins Construction,L.L.L.P., Ne-1 Res.—Traalee— —
Robins ock Pit,File No.M-2007-080
R
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.
I. 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the 1960s,and has been superseded by the Scaled Distance Equation,which is based on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/D,)'
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=0to300R.,Ds-50
for D=301 to 5000 R.,Ds=55
and for D=5001 R.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
Wow,the location of the Haberkon House 0.8 miles from the blast site is the controlling factor for
blasting.
DISTANCE—Ff. 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
ice of c Nf m of
Mined Land Reclamation Denver• Grand lunction Durango Active and Inaxiiw Mines
Job # 1200710MP - C Pagel 73of79