High PGE potential in the Matagami area

Jean Goutier
Géologie Québec

Recent mapping fieldwork and mineral inventory by the Department has allowed, among other things, to characterize the platinum group elements (PGE) mineralization of the rivière Bell Complex and to suggest exploration guides for this area. The rivière Bell area (NTS 32 F/10, 11 and 12) presents fundamental characteristics favourable to the occurrence of rare metals of the platinum group elements. The main showings recorded on this little explored, huge territory already seem to indicate an association with different geological contexts, even if they are separated by slightly more than 10 kilometres. The possibility to discover other sites with PGE economic grades in the area remain therefore very high.

Historical background

The rivière Bell Complex is a large magmatic intrusion (20 km by 65 km) located on both sides of this river in the Matagami area. As early as the first mapping fieldwork of the 1930’s, geologists have compared this intrusion to the Bushveld of South Africa. The rivière Bell Complex is known for its association with the zinc-, copper- and silver-bearing massive sulphide deposits of Matagami. Moreover, showings of copper, nickel, vanadiferous magnetite, and titanium also occur in this intrusion (figure 1). The discovery of the first two PGE showings in the area by SOQUEM goes back to the beginning of the 1990’s. The showings are Ebay, BWest and Dotcom.

Table 1: List of the three PGE showings of the rivière Bell Complex

The recent mapping fieldwork by the Department and exploration activities by the industry have shown that these showings correspond to three mineralization types, including the two so-called classic types. The Ebay showing corresponds to the stratiform type formed by a PGE-enriched magma. Some levels, such as the extension of this showing, are worth prospecting with the hope of finding other enriched zones. The best showing is associated with a shear zone.

This type of structure is frequently PGE-enriched like the Shear Ore of the Lac des Iles deposit. The Dotcom showing is associated with the intrusion breccia type. The geochemistry of this rock indicates that it is a distinct intrusion which can also be found outside the Complex.

Figure 1. Location of PGE in the rivière Bell Complex near Matagami, and distribution of the other mineralized showings associated with this magmatic intrusion.

The PGE in the world

PGE are rare metals grouping together platinum, palladium, rhodium, ruthenium, iridium and osmium. These metals are corrosion resistant and their melting point is very high. The production of car catalysts is one of the main uses for PGE. Moreover, PGE are in demand for electrical applications, manufacturing of laboratory crucibles and numismatic coinage (collector coinage), dentistry and jewellery. At the moment, palladium, platinum and rhodium are worth respectively less than half, twice and three times the gold price.

South Africa and Russia are the main producers of PGE. Canada and the United States are lesser producers. PGE are found in primary deposits or as by-products of copper and nickel deposits such as Raglan in Nord-du-Québec or Sudbury in Ontario. Primary PGE deposits are divided in two categories: stratiform or intrusion breccia. Stratiform deposits are associated with large magmatic intrusions and form the most important PGE deposits in the world, such as those found in the Bushveld intrusion of South Africa. Deposits associated with intrusion breccias are linked to much smaller intrusions. The intrusion breccia type Lac des Iles deposit north of Thunder Bay, Ontario, is the only primary PGE mine in North America.