| Gold and silver were mined at the
Canadian Malartic mine between 1935 and 1965,
producing 9.9 Mt of mine tailings.
Between 1962 and 1968, Marbridge
Mines also processed 702,000 t of nickel-rich
and copper-rich ore on the site. The Canadian
Malartic mine tailings site consists of a
78-hectare flat base of gold ore tailings,
underlying a 3 to 5 metre high mound
covering 43 hectares. The acid-producing
sulphur-rich tailings are spread over the
surface of the mound to a thickness of between 1
and 2 metres. |
The Canadian Malartic site,
as it appeared in 1992 after more than
20 years of abandon. |
A hydrogeochemical characterization
study carried out in 1992-93 led to a considerable
reduction in the cost of the rehabilitation work,
initially estimated at several million dollars
because of the presence of sulphurous tailings
with a high potential for acid drainage, and the
area of the site. The rehabilitation plan uses
the neutralizing potential of the underlying gold
ore tailings, and the presence of an indurated
layer formed by the cementation of the secondary
phases, mainly sulphates, at roughly one metre
below the surface of the sulphurous tailings.
The cementation considerably reduces oxygen dispersal
and the oxidization rate of the sulphurous material.
The same site, after the 1996
restoration work. |
The site was restored in 1996
at a cost of $1.37 million, mainly in
order to ensure that surface water could percolate
through the layer of alkaline gold ore residue
and to limit wind and water erosion at the
surface. The work involved displacing some
of the tailings, flattering overall slope,
stabilizing the surface, installing a drainage
system, and finally, amending and seeding
the surface. |
References
Tassé, N., Germain, D.,
Dufour C., Tremblay, R., 1997. Hard-pan formation
in the Canadian Malartic mine tailings: Implication
for the reclamation of the abandoned impoundment.
In: Proceedings of Fourth International Conference
on Acid Rock Drainage, Vancouver (British Columbia),
Vol. IV, pp. 1797-1812.
Tassé, N., Germain, D.,
Dufour C., Tremblay, R., 1996. Dynamique de
l'altération au parc Canadian Malartic :
implication pour les mesures de restauration.
Compte rendu du Colloque NEDEM sur le programme
de neutralisation des eaux de drainage dans l'environnement
minier. Rouyn-Noranda (Québec) 29 au
31 octobre, 1996, Vol. 2, pp. 239-258.
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