PERMFILE117747

• Permit No: M1988112
• IBM Index Class Name: Permit File
• Doc Date: 3/2/1989
• Section_Exhibit Name: APPENDIX I PROPOSED GEOTECHNICAL PROGRAM
• Media Type: D
• Archive: No

STEEPEN ROBERTSON AND KIRSTEN
Consulting Engineers November 23, 1988
SRK Project No. 14702
Battle Mountain Gold Company
' P.O. Box 1600
Alamosa, Colorado 81101
' Attention: Mr. Gary Dodson
RE: PROPOSED HYDROGEOLOGIC/GEOTECHNICAL EVALUATIONS. SOUTH WALL OF WEST PIT.
SAN LUIS PROJECT
Dear Gary,
' ~ The purpose of this letter is to present the proposed field exploration
and laboratory testing program to evaluate the hydrogeologic and geotechnical
characteristics of the Santa Fe Formation in the south wall of thEr west pit of
the San Luis Project. The program has been developed by Steffen Robertson and
Kirsten (Colorado) Inc. (SRK) in consultation with Halepaska and Associates,
Inc., (Halepaska). We anticipate that SRK will be responsible for the
geotechnical aspects of the program and that Halepaska will take responsibility
' for the hydrogeologic aspects.
Introduction
' The purpose of the proposed study is to evaluate the potential
hydrogeologic connection between the Rito Seco and the west pit through the Santa
Fe Formation. In addition, the study will address the impact of the groundwater
t regime on the stability of the pit wall. The proposed study will address the
following questions:
' ) 1. What is the hydraulic conductivity of the Santa Fe Formation and what
impact does the Rito Seco have on aquifer recharge?;
' 2. What is the nature of the water pressure regime between the Rito Seco
and the open pit?; and
3. What effect will the groundwater regime and exposure in the pit wall
have on the strength characteristics of the Santa Fe Formation?
Scooe of Work
' The proposed field exploration program consists of from tfcree to six
vertical coreholes located along the edge of the proposed south wall of the west
pit within the Santa Fe Formation. Each of the coreholes will be located between
' the proposed top of pit wall and the Rito Seco. We anticipate that three of the
coreholes will be used for geotechnical sampling and hydrogeologic testing
purposes. The remaining three coreholes will be completed only if deemed
1 necessary to obtain additional geotechnical or stratigraphic information. The
first three coreholes will be located 100 ft west, 100 ft east, and 300 ft east
of borehole D88-63. The remaining coreholes, if determined to be necessary, will
t be located 200 ft west, 200 ft east, and 400 ft east of boreholes DES-63.
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