The Témiscamingue region: a high-potential sector for nickel, copper, cobalt and platinum group elements
Pierre Doucet
Géologie Québec

A staking rush marked the Pontiac geological Subprovince, more specifically the southern part of the Témiscamingue region, in early 2001, following the announcement on December 11, 2000, by Aurora Platinum Corporation, of important drill intersections of Ni-Cu-Co-PGE (platinum group elements) mineralization on the Midrim-Belleterre-Angliers property, 20 km northeast of Ville-Marie. Following the press release, several prospectors and companies rapidly acquired, through map designation or joint venture agreements, properties in the Baby-Belleterre greenstone belt. The southern part of the Pontiac Subprovince thereby joins the list of potential sectors in the search for Ni, Cu, Co, PGE, along with the Ungava Trough, the eastern part of the Labrador Trough and the area west of Chibougamau. For more information, readers can consult the 1:2,500,000 scale map published by the MRN (DV-2002-04), which shows the location of Ni-Cu-PGE occurrences in Québec.

Previous Work

Mineral exploration in the Témiscamingue region dates back to the arrival of the first settlers in northwestern Québec. First, between 1887 and 1902, a lead, zinc and silver deposit was mined intermittently along the eastern shore of Lake Timiskaming. Then, gold mineralization was reported in the Belleterre area in 1933, and an ore deposit bearing the same name was mined between 1936 and 1959. The Lorraine copper-nickel mine, further west, was discovered in 1961, and mined between 1964 and 1968. It produced 600,000 tonnes of ore at a grade of 1.08% Cu and 0.48% Ni. During the 1980s and early 1990s, diamond exploration in the Saint-Bruno-de-Guigues area, involving important stakeholders such as Canabrava Diamond Corporation and Monopros Limited, led to the identification of four kimberlite pipes. Despite the discovery of a few diamonds, the exploration frenzy soon died down, and diamond exploration in the Abitibi-Témiscamingue region was virtually non-existent for several years.

Recent announcements, namely reports of kimberlite indicator minerals in the Baie-James region, and the discovery of two diamond-bearing kimberlitic bodies in the Monts Otish, in the Near North region, in December 2001, rekindled exploration interest in many other sectors of the Superior Province, including in the Témiscamingue region. Finally, numerous industrial mineral operations, such as silica and lime, and architectural stone quarries were in operation in the Témiscamingue region throughout the 20^th century.

Geology

The Pontiac metasedimentary Subprovince is composed of 55% granitoid intrusions and orthogneiss, found in the central part, 40% detrital sedimentary rocks and paragneiss, along with 5% volcanic rocks (Figure 1, PDF Format, 0,97 Mb). The latter form ultramafic, mafic and locally felsic assemblages in the southwestern Pontiac Subprovince. A few thin bands of mafic to ultramafic volcanic rocks are present along the northern margin. The Pontiac Subprovince is separated from the Abitibi Subprovince by the Cadillac – Larder Lake fault, an important structure that extends over a distance of more than 100 kilometres along an east-west axis, in Québec and Ontario. Undeformed Proterozoic sedimentary rocks of the Cobalt Group overlie, atop an erosional unconformity, the southwestern Pontiac, and further north, a segment of the Cadillac – Larder Lake fault. Eastward, the Pontiac Subprovince is bounded by the Grenville Front, a major Proterozoic tectonic zone that stretches over a distance of nearly 1,200 kilometres in Québec alone. Based on data from the Ministère des Ressources naturelles, 20 Ni-Cu showings are reported in the Pontiac Subprovince (Figure 1, PDF Format, 0,97 mb). Along the northern segment of the subprovince, this mineralization is generally associated with bands of mafic-ultramafic rocks, such as in the Lac Opasatica sector, whereas in the southern part of the subprovince, mineral occurrences are mainly associated with gabbro sills or horizons inserted in mafic volcanic sequences of the Baby-Belleterre belt. The Baby-Belleterre belt extends from east to west over nearly 60 km, and reaches up to 5 km wide.

Exploration for Ni-Cu-Co-PGE

Throughout 2001, Aurora Platinum released results from its exploration program on the Midrim-Belleterre project, which groups the Midrim (Midrim, Midrim West, and Lac Croche showings) and Belleterre (Alotta, Delphi, Patry, Zullo, and Duchesne showings) properties. The Ni-Cu-Co-PGE mineralization under study is generally associated with magnetite-rich gabbro sills and ultramafic rocks that contain disseminated sulphides in the upper part, and massive sulphide accumulations at the base of the sills. The company has completed mapping and geochemistry surveys as well as airborne and ground geophysical surveys, excavation of several trenches, over 120 diamond drillholes, and petrology studies. This work required a total investment of over $2.5M, and a similar amount is set aside for the 2002 campaign.

The first drillholes completed in the fall 2000 had yielded significant grades at shallow depths. In the spring and summer 2001, the company released new drill results, just as impressive as the first series, on the Midrim, Midrim West, and Alotta zones. The company also reported it had discovered a new mineralized zone at depth on the Midrim showing, and also announced a kimberlite discovery.

Tom Exploration inc. released, at the end of January, encouraging results from its first drillhole on the Laverlochère property, adjacent to the Midrim-Belleterre-Angliers properties held by Aurora Platinum Corp. In August 2001, Loubel Exploration and Tom Exploration released preliminary results from prospecting work conducted on the Kelly Lake property in Blondeau Township, where Cu-Ni showings were stripped. Drillholes testing these showings during the first months of 2002 yielded encouraging intersections, namely 14.8 m grading 1.01% Ni, 0.63% Cu, 0.051% Co, 0.44 g/t Pt, and 0.49 g/t Pd in drillhole K-02-117. Note that the Kelly Lake deposit contains a mineral resource of 2.4 Mt, at a combined grade of 1.4% Ni+Cu.

Outlook

The positive results obtained by Aurora Platinum Corp. and partners Loubel Exploration and Tom Exploration confirm the mineral potential for Ni-Cu-Co-PGE mineralization associated with mafic sills in the Baby-Belleterre belt. Work currently underway is focussed on delineating extensions to known ore zones, and thus increase the tonnage of these deposits, which may eventually lead to a mining operation. The important volume of mafic lavas and sills in the Baby-Belleterre belt suggests that the potential for new discoveries is excellent. Finally, the new wave of diamond exploration in Québec, which has touched the Témiscamingue region, along with the discovery of a new kimberlite pipe east of Ville-Marie by Aurora Platinum Corp., suggest that the potential for diamond exploration and the discovery of new kimberlite pipes in the area should not be underestimated.