REV01477

• Permit No: C1994082
• IBM Index Class Name: Revision
• Doc Date: 5/12/1999
• Doc Name: REVIEW OF PR 01 YOAST MINE C-94-082
• From: DMG
• To: MIKE BOULAY
• Type & Sequence: PR1
• Media Type: D
• Archive: No

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STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Departmem of Natural Resources
1313 Sherman 8t., Roam 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]?-8106
Date: May 12, 1999
To: Mike Boulay
From: Harry Ranney
Re: Review of PR-Ol, Yoast Mine, C-94-082
DIVISION OF
MINERALS
GEOLOGY
RECLAMATION
MINING•SAFETY
Bill Owens
Governor
Greg E Watcher
6ecutrve Director
Michael B. Long
Division Director
I have completed my review of the portions of PR-Ol concerning the design of haul roads B-Ex[, C, and D, as
well as the haul road drainage's and permanent drainage's YPM-l through YPM-I 1.
The majority of the engineering work for the drainage's was completed by the Montgomery/VVatson firm.
The firm utilized Sedcad 4, version 1, dated August 1998 for the numerical computations. It was noted and
verified by com~ersations with Dr. Wamer of Civil Software Design, that this version was released prior to
incorporating all error trapping into the program which would catch any design or computation error and Flag
it for redesign. This fact alone accounted for numerous channel failures that I discovered in my review. As
of approximately two weeks ago, the firm has informed me that i[ has upgraded their copy to the latest
version. The version is the same that the Division currently uses.
4.03.1 Haul Roads.
1. (1) (e) The design for haul roads shnll be based orr geometric criteria approprinre for the
anticipated volume of traffrc artd weight and speed ajvehicles to be used.
Page 12, Tab 13 of the permit, paragraph 5, SCC states that this will be done, however, nowhere in
the permit, including Attachments 13-5 and 13-6 could I find where this information was considered.
These referenced attachments apply to haul roads A and B, and not [o B extension, C or D.
SCC has not submitted any information that indicates that soil samples at the proposed haul
road sites have been taken for engineering analysis. This fact alone severely hampers any site-
specific engineering to occur to include stability, erodibility, compaction (Proctor), California
Bearing Ratios to name a few.
2. (1)(e) ... in addition to the referenced demonstration, npproprinte engineering tests establish
compliance Kith a rrrinirnunr static safety factor of 1.3.
Paragraph 3, page 12, Tab 13, states " In the unlikely case that a haul road could be routed across a
portion of an unconsolidated surficial landslide, SCC will conduct a geotechnical investigation to
determine the characteristics and extent of any possibility".
The horizontal alignment of haul road B extension traverses a known landslide, yet, as mentioned
above, no samples of [he area in question were taken and therefore no site specific stability analysis
can be performed.