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The rehabilitation os State-owned mining sites
$20 million invested
Johanne Cyr
Direction du développement minéral
| The mining industry has acquired an unflattering
reputation, after abandoning countless mine tailings sites to
erosion by wind and water and to oxidization processes that
lead to the production of acid mine drainage. Other problems
include abandoned waste rock dumps, trenches and other dangerous
openings, unsecured infrastructures and machinery, and badly-stored
products of varying toxicity. |
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To ensure that situations like these will not occur
in the future, the gouvernement du Québec introduced changes
to the Mining Act on March 9, 1995. Since then, whenever mineral
exploration or mine extraction activities are undertaken, a rehabilitation
plan must be submitted and a financial guarantee covering 70% of
the foreseeable cost of rehabilitation work on stocking areas must
be deposited by the mining company concerned.
The program to restore State-owned mine sites
Between 1967 and 1985, 11 mine sites, covering
a total area of more than 500 hectares, were transferred back
to the government by the mining industry. They are located in Abitibi-Témiscamingue
(East Sullivan, Sullivan, Terrains Aurifères A, Canadian
Malartic, Wood Cadillac, Preissac, Stadaconna and Lorraine), Mauricie
(Somex) and Gaspésie (Candego and Les Mines Madeleines).
In view of the extensive environmental problems caused by these
mining sites, the Department launched a rehabilitation program for
State-owned mining sites in 1987. Since 1991, over $20 million
has been invested in the program.
A great deal of energy has been directed at the
development of efficient, economical restoration methods. Many different
experts from the university and engineering consultancy fields have
contributed to the work undertaken by the Department. In several
cases, an exhaustive characterization of the site concerned has
led to the development of innovative technological approaches using
various residual materials, such as forest residue, sludge from
sewage treatment plants, septic tanks or paper mills, and ash from
co-generation power plants. These technologies have reduced costs
and offered a solution to the problem of stockpiling at least some
of the residues concerned. Various studies have also been carried
out to develop passive treatment systems adapted to the specific
parameters of mine effluents (biofilters, wetlands, limestone drains,
organic barriers, etc.).
As an illustration, the following pages describe
the results of some of these mine rehabilitation projects.
Recognized expertise
The rehabilitation of State-owned sites has led to the development,
within Québec, of recognized expertise in site characterization,
the understanding of mine tailings alteration processes, and the
development of effective and economical technologies. In addition,
the use and revalorization of various types of residue, the design
of passive treatment systems and the integration of wildlife habitat
creation as part of the mine site rehabilitation process are entirely
in keeping with a concept of sustainable development.
The MRN must now work to promote technology transfers
and the diffusion of knowledge in the underworld to ensure that
its expertise is put to good use, while continuing to focus on research
and technological innovation. Although the restoration of the sites
transferred back to the State has now been practically completed,
many other sites that have been abandoned over the years still await
restoration.
The mining companies that ceased their operations
before the amendments to the Mining Act came into force are not
required to provide rehabilitation plans or financial guarantees,
but they still remain responsible for the tailings produced at their
mines. However, there are around 70 sites where the companies concerned
either cannot be traced or are insolvent, and are therefore unable
to carry out the work required. 15 of these sites are considered
to have a major impact on the environment, and must be prioritized
for future work. The estimated cost of restoring these 15 sites
is around $40 million, and the total cost for all abandoned
sites could reach $70 million.
Bibliography
- Bertrand, P. and J. Cyr. Restauration du site minier Sullivan
: un concept écologique d'aménagement. Vecteur environment-
Volume 34, number 4, July 2001.
- Isabel, D., N. Tassé, C. Dufour and F. Bergeron. Traitement
des résurgences d'un parc à résidus miniers
au moyen d'un biofiltre réducteur. Colloque Nedem 2000,
October 3-5, 2000, Sherbrooke.
- Dagenais, A.M., M. Aubertin, B. Bussière, L. Bernier
and J. Cyr. Monitoring at the Lorraine mine site : a follow up
on the remediation plan. 2001 National Association of Abandoned
Mine Lands Annual Conference, August 19-22, 2001, Athens, Ohio.
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