1991-09-20_HYDROLOGY - M1977378

• Permit No: M1977378
• IBM Index Class Name: HYDROLOGY
• Doc Date: 9/20/1991
• Doc Name: Geotechnical Engineering Exploration- Tailings Pond #1
• From: Western Technologies Inc.
• To: San Juan County Mining Venture
• Permit Index Doc Type: Hydrology Report
• Media Type: D
• Archive: No

Geotechnical Engineering Exploration
Tailings Pond No. 1
Sunnyside Mine
Silverton, Colorado
INTRODUCTION
This report contains the results of our geotechnical engineering
evaluation of the south slope for the existing Tailings Pond No . 1
at the Sunnyside Mine, located approximately 2 miles north of
Silverton, Colorado. The purpose of these services is to:
o Provide results of field and laboratory testing;
o Determine the stability of the past failure area in its
current configuration;
o Determine the possibility of a slope failure of the
tailings into Boulder Creek;
o Determine the stability of slope if reconstructed to a
2 . 5 : 1 (horizontal to vertical) configuration;
o Determine the ability of the past failure area of the
tailings pond to support a limited amount of additional
fill during reclamation; and,
o Evaluate the stability of the pond under pseudo-static
(seismic) considerations.
EXISTING CONSTRUCTION
The existing tailings pond is approximately 400 by 1800 feet in
plan dimension at the top of the embankment, with a maximum
existing height of approximately 105 feet on the southeast side.
The bottom of the pond is approximately 750 by 1800 feet .
Existing slopes are on the order of 1. 5 to 1 (horizontal to
vertical) .