PERMFILE135944

• Permit No: M1993041
• IBM Index Class Name: Permit File
• Doc Date: 10/13/1993
• Doc Name: GROUND VIBRATION STUDY SOUTHWESTERN PORTLAND CEMENT DOWE FLATS QUARRY FN M-93-041
• From: DMG
• To: BILL YORK FEIRN
• Media Type: D
• Archive: No

:IQT ~ OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Department of Natural Resources
1313 Sherman St., Room 215
Denver, CO 80203
Phone: [phone]
FAY: 1303) 832-8106
October 13, 1993
TO: Bill York-Feirn
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Roy Romer
Governor
Michael B. Long
Div rsion Director
FROM: Allen Sorenson ~ S -
RE: Ground Vibration Study, Southwestern Portland Cement, Dowe
Flats Quarry, File No. M-93-041
I have reviewed the report on blasting impacts prepared by SHB
AGRA, Inc. in support of the above referenced application.
Essentially, the applicant has chosen to develop a site specific
modified scaled distance equation. The scaled distance equation
was developed based on data obtained from blasts in the nearby
Lyons Quarry; the point is made that the sites are geologically and
geomorphologically similar, so that the equation developed for the
Lyons Quarry will be valid for the Dowe Flats Quarry.
The Division can accept this hypothesis only to the point that use
of the equation developed for the Lyons Quarry can be used to
govern initial blasting at the Dowe Flats Quarry. Once sufficient
data has been collected at the Dowe Flats Quarry, a modified scaled
distance equation must be developed that is specific to Dowe Flats.
The operator should be made aware that the Division will require
that at least 30 data pairs (peak particle velocity versus scaled
distance) be collected for the analysis and that the coefficient of
determination of the data be no less than 0.7.
Table 1 included in the SHB AGRA report indicates that the
applicant has collected the type of data that is appropriate to
develop a modified scaled distance equation (e.g. measured
distances, measured explosive weights, separately identifiable data
recorded for overburden blasts and production blasts, etc.),
however, the applicant should be apprised of the need to collect
data at as wide a range of scaled distances as possible, certainly
at as low a scaled distance as it is hoped will be authorized, and
that consistency of data collection requires use of the same
instrumentation for each recording.
I would recommend that the applicant agree to the following
commitments prior to permit issuance:
1. The modified scaled distance equation developed for the Lyons
Quarry will govern blasting operations at the Dowe Flats
Quarry initially. All blasts at the Dowe Flats Quarry will be
monitored until a sufficient number of data pairs are