PERMFILE134536

• Permit No: M1997054
• IBM Index Class Name: Permit File
• Doc Date: 7/31/1997
• Doc Name: REVIEW OF PARKDALE PROJECT APPLICATION FN M-97-054
• From: DMG
• To: LARRY OEHLER
• Media Type: D
• Archive: No

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STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Dcpartmcnl u1 NJluml Rrwurces
1111 )h~~rm.in St.. Room CIS
Dcnvcr, Colorado HO'_03
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To: Lam Oehler
From: James Dillie il~
Date: July 31, 1997
Re: Review of Pazkdale Project Application, File No. M-97-054
~~~~~~~~
DEPARTMENT OF
NATURAL
RESOURCES
Ruy Romer
Governor
IJmes 5. tochhrad
Execmive Duecmr
Micharl B. EonR
Division Director
At your request, I reviewed the referenced permit application. Specifically, I attempted to
evaluate stability of the quarry highwalls, the effects of blasting operations and the adequacy of
the proposed installation of culverts in Tallahassee creek.
The applicant did not submit sufficient data to complete an evaluation of any of the operations.
The operator did submit a minimal amount of information for the quarry highwall; height and
width of the cuts and benches (plus the overall slope angle). However, since it appeazs the overall
slope angle will be steeper than the internal friction angle, I will need a few more details about
the local geology. First, is the granite altered or unaltered. Second, what is the strike and dip of
the predominant fracture systems. Third, What is the elevation of the phreatic surface (if any).
Fourth, what earthquake coefficient did the operator use to determine that the highwall feature is
well within reasonable and conservative engineering limits for a long term safety from the
standpoint of overall slope stability.
Other than stating that scaled distance formulas will be used to establish safe seismic
disturbances and air blast limits, the applicant did not submit any data concerning the effects of
blasting operations. Of the available compliance options the applicant chooses to submit a scaled
distance analysis using the scaled distance equation to determine maximum chazge weight per 8
ms delay. This is the simplest of all ground motion compliance options so it will not be difficult
to submit the analyses prior to permit approval. The applicant should determine a chazge weight,
or scaled distance, for all structures within 5000 feet of the quarry. Also, the applicant should
address the potential flyrock problem. What safety measures will the applicant commit to in
order to protect the public from flyrock?
Finally, the applicant proposes to install culverts in Tallahassee creek. How did the applicant
decide what size culvert to use? The applicant should submit a detailed analysis showing the
watershed area and potential runoff amounts so the Division can determine if the culverts aze
properly sized. Also, the applicant states that sediment control structures will be constructed in
the permit area. However, the applicant did not submit any data regarding the size of the
structures or their capacities.
Let me know when the applicant submits the above noted information so 1 can review it.