REP22489

• Permit No: M1988112
• IBM Index Class Name: Report
• Doc Date: 6/10/1994
• Doc Name: 3RD PART TECHNICAL OVERSIGHT REPORT FOR THE SAN LUIS PROJECT TAILINGS DISPOSAL AREA PHASE II RAISE I
• Media Type: D
• Archive: No

Third Party Oversight 4 Weter, Waste & Lend, Inc.
Sen Luis Mine June 9, 1994
1
2.0 REVIEW OF DESIGN AND GEOTECHNICAL ISSUES
t Pertinent documents concerning the design and construction of the existing facility and
the planned expansion to the tailings impoundment system were reviewed prior to WWL's
initial site visit. The focus of the review was on the key geotechnical issues associated with
' the Raise I Expansion, and how the expansion related to the intent of the originel Phase I and
Phase II designs.
2.1 INITIAL DESIGN REVIEW
WWL's evaluation of the design for the expansion reflected our review and
understanding of documents concerning design, construction, and monitoring of the original
(Phase q embankment and the Phase 11, Raise I Embankment; previous site exploration work
and testing; site and construction material conditions; and, tailings disposal procedures at the
time of our initial site visit. Information sources utilized in our initial evaluation are listed
below.
' ^ Technical documents reviewed prior to the initial site visit included
^ 1 12 Permit Application for the San Luis Project, (BMRI, 'i 989).
^ 112 Permit Application Amendment for the San Luis Project, (SRK,
1989).
' ^ San Luis Project Permit Amendment Adequacy Responses, M-88-112,
(SRK, 1990).
^ San Luis Project Tailings Impoundment Construction Report, (SRK,
' 19911.
^ San Luis Mine Phase I1, Raise I Design Report, (SRK, 1993a1.
^ Construction Status Report, San Luis Project Tailings Disposal Area,
Phase II, Raise I, (SRK, 1993c).
^ The initial site visit and meeting with DMG and BMRI staff on October 28, 1993
and additional meetings and conversations with DMG staff.
' ^ Geotechnical monitoring data collected prior to and after initiation of construction
of the original (Phase I) embankment.
^ Various correspondence, submittals, and revisions pertinent to the design and
intent of the expansion reviewed prior to the site visit.
' ^ Review of laboratory and QA/OC test results conducted after initiation of
expansion construction and prior to initiation of the third-party oversight work.
2.2 DESIGN INTENT
' Based on WWL's review of the documents listed above, our understanding of the
design intent of the tailings disposal facility pertinent to Raise I Expansion is summarized in
the following paragraphs.
LJ