GENERAL40028

• Permit No: M1980244
• IBM Index Class Name: General Documents
• Doc Date: 10/26/1994
• Doc Name: GEOMEMBRANE PERFORMANCE WHEN TESTED WITH THE ROCK PLACED IN THE LINER COVER FILL
• From: GOLDER ASSOCIATES INC
• To: DMG
• Media Type: D
• Archive: No

Golder Auoeiates Ine.
200 Union Boulevard. Swte 500
Lakewood. CO USA 80228
Telephone [phone]
Faz(303)985-2080
October 26, 1994
Colorado Department of Natural Resources
Division of Mines and Geology
Office of Mined Land Reclamation
1313 Sherman Street, Room 215
Denver, Colorado 80203
Our ReY'.: 943-2732
Attention: Mr. Berhan Keffelew, Environmental Protection Specialist
RE: GEOMEMBRANE PERFORMANCE WHEN TESTED WITH "THE ROCK"
PLACED IN THE LINER COVER FILL
Dear Mr. Keffelew:
The following report contains the results of the first of two static heap overburden load tests
of liner cover fill placed directly on a 80-mil VLDPE geomembrane, underlain by soil liner
fill (Ironclad tailings). The samples of liner cover fill containing the "The Rock",
geomembrane, and soil liner till were obtained from project specific materials that were
removed from the placed fill. The Rock specimen was identified by Mr. Bruce Humphries
of your office and obtained from the liner cover fill that had previously been placed on the
geomembrane surface.
A 10-inch diameter percolation cell was used to confine the layers of drain cover fill,
VLDPE, and soil liner fill. The composite layers were subjected to a static load of 300 psi
(approximately 375 feet of equivalent ore) overnight. The cell was then dismantled and the
VLDPE was evaluated for deformation and damage. The purpose of this type of large scale
performance testing is to determine what, if any, mechanical damage will occur to the
geomembrane when subjected to static heap loads in excess of those anticipated during the
operation of the heap leaching facility.
SAMPLE PREPARATION
Samples were placed in the cell in a condition similar [o placement on the pad. Soil liner
fill was near optimum moisture content and compacted to a wet density of approximately 141
pounds per cubic foot. That value is consistent with field measurements of soil liner till
recently obtained during consuvction. The sample of soil liner fill was obtained from the
heap leach pad after the fill had been dumped from a truck and prior to compaction. The
sample generally contained material that was less than 3/4-inch in size but consistent with
the material being placed on the pad, contained some gravel pieces between the 3/4-inch and
2-inch fraction.
999
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