2003-05-30_REVISION - M1980244 ‎(3)‎

• Permit No: M1980244
• IBM Index Class Name: Revision
• Doc Date: 5/30/2003
• Doc Name: 4 Inch LVSC Pipe
• From: CC & V
• To: DMG
• Type & Sequence: AM8
• Media Type: D
• Archive: No

Golder Associates inc.
44 Unlon Boulevard. Suite 3(~
lokewaod. CO USA 80228
Telephone <3Q3) 980-0540
Fqx (303) 9862080
May 29, 2003
Cripple Creek & Victor Gold Mining Company
P.O. Box 191
2755 State Highway 67
Victor, Colorado 80860
Attention: Mr. Ron Roberts
RE: 4INCH LVSC PIPE - RIF NO. 103
Dear Ron:
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Our Ref: 003-2203
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Golder Associates inc. (Golder) has prepared this letter for the Cripple Creek & Victor Gold Mining
Company (CC&V) regarding Request For Information (RFI) No. 103 submitted by Ames
Construction, RFI No. 103 addressing the 4-inch perforated Low Volume Solution Collection
(LVSC) pipe that was not installed during construction of the Phase N PSSA.
Golder has reviewed the design of the LVSC system with the missing pipe removed and has
concluded the following:
• The LVSC pipes were originally included in the PSSA design to augment drainage from the
LVSC fill to the LVSC sump. By itself, the LVSC fill permeability is sufficient to transmit
potential seepage from the upper liner to the LVSC sump. Using the EPA guidelines for
estimating seepage from lined facilities set forth in EPA/530/SW-87-015 and EPA/625/4-89-
022, Golder has estimated the LVSC fill has approximately three times more flow capacity
than the theoretical seepage from the upper PSSA liner.
• The permeability of the LVSC fill has been tested up to loads equivalent to 590 feet of ore.
The lab tests indicate that the permeability of the fill remains at 0.1 centimeters per second
(cm/sec} even under the anticipated ore loads.
• The intent of the LVSC pipes was to shorten the flow path to the sump, this is most important
for the western side of the PSSA where the flow paths are significant (on the order of
thousands of feet). The 4-inch pipe that was not installed was located in the eastern portion of
the PSSA, where the flow paths are the shortest (350 feet).
Based on these conclusions, Golder will approve construction of the Ahase IV PSSA sump with the
missing 4-inch LVSC pipe referenced in RFI No. 103.
Golder appreciates the ongoing opportunity to provide engineering services for the Cresson Project.
Please contact the undersigned with any questions.
Sincerely,
GOLDER ASSOCIATES INC.
n F. Lupo, Ph.D., P.E.
Sr. Project Manager
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