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RGC: Project Experience
Les Mines Selbaie
Quebec, Canada
- Client:
- Billiton Metal Canada Inc.
- Years of Service:
- 1992
- Project Description:
- Les Mines Selbaie is a 7600 tonnes per day copper-zinc mill and mine
which involves both
underground and open pit workings. Copper and zinc flotation concentrates are
shipped off-site for
further processing. Other components of the mine site include overburden piles,
mine rock piles, tailings
impoundment and clarification pond. The mine rock has been segregated into
highly acid generating, acid
generating and non-acid generating piles. The initial tailings disposal system
was based on the Robynski
method of thickened tailings placed from a central discharge to form a cone.
This system has been
replaced by a conventional spigotted discharge and system of surrounding
dykes. The clarification pond
is used to settle fines from water draining from the tailings disposal system.
Selbaie has been
experiencing increasing acidic drainage from the mine rock piles, mine rock
berms and tailings deposits.
The acidity is controlled using a water treatment plant utilizing lime.
- Services Provided:
- Dr. Robertson was the Project Principal and Senior Technical
Leader of the SRK team that was retained by Billiton to carry out a
preliminary environmental liability evaluation followed
by a more detailed environmental audit for the mine site as part of their pre-
acquisition due diligence.
- Environmental Liability Evaluation
A pre-acquisition site reconnaissance was conducted to assess current and
potential issues of
environmental liability. Inspections were made of the major mine and mill components, the property
compliance data was reviewed and site personnel interviewed. These were non-sampling assessments,
based on field observations and technical review of the main components at the site. Consequently, the
liability assessments and cost estimates relied, to a large extent, on our experience and engineering
judgement. Closure plan options were developed to address the major issues, with an estimate of the
costs for implementation of the recommended options.
- Environmental Audit
The objective of this phase was to complete the detailed site environmental audit. Where possible, this
phase of data gathering and evaluation followed work previously done on site. There were components
of the audit pertaining to acid rock drainage and mine environmental liability and costs that had not been
identified previously. In assessing financial liability, compliance under current permit or regulatory
requirements was assessed and also the additional environmental liability considered likely in the near
future (less than 10 years) under the prevailing regulatory trends.
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