Published:January 01, 1991
Audrey Resources Inc.'s Mobrun Mine is located in Dufresnoy Township, some 30 km northeast of Rouyn-Noranda, in Northwestern Quebec (Fig. 1). Rio Algom discovered The Mobrun Main Lens by means of a mobile road E.M. survey. Until 1985, the drill estimated 3.3 million metric tonnes of massive sulphides were not considered economic. Increasing metal and gold prices enabled Audrey start selective production in June 1986 for metallurgical testing purposes.
Underground development and detailed diamond drilling on the Main Lens have outlined 1 523 000 t of economical massive sulphides (proven reserves) grading, 0.80 % Cu, 2.44% Zn, 30.19 g/t Ag, and 2.2 g/t Au (to a depth of 300m) to be outlined, of which 465 000 t have been mined.
Additiona1 dri11 indicated reserves, pertaining to the 850-870-930 Lens system, total 180 000 t grading; 1.20% Cu, 2.41% Zn, 42.23 g/t Ag, and 4.98 g/t Au, to a depth of 300m. These satellite lenses, discovered while attempting to delineate the eastern extension of the Main Lens, are accessible through development on levels 4, 5, and 6 (respectively 200, 250, and 300m below surface).
Subsequent surface drilling in 1988, aimed at defining the eastern depth extension of the 930 Lens, defined a strong Pulse E.M. anomaly with a source beneath the holes. On March 30, 1988, discovery hole, Au-88-42, cut 17.6 m of semimassive sulphides followed by 18.6 m of massive sulphides. As of February 1989, probable economical reserves for the 1100 Lens stood at 10 400 000 t grading 0.76 % Cu
Figures & Tables
Control on Base Metal and Gold Mineralizations, Bousquet—Rouyn-Noranda Area*
The Archean Abitibi belt is one of the largest and most studied greenstone terranes in the world. This is due not only to its precious and base meta 1 production, but also to its excellent bedrock exposure which permits observation of many Archean geological features in the south part of the belt lying between Rouyn-Noranda and Val d'Or.
The main objective of the regional field trips and the mine visits is to present the rna in stratigraphic, st ructura 1 and ore characteristics of the southern part of the Abitibi Belt. This regional field trip is scheduled to cover the Rouyn-Noranda and Cadi 11 ac-Bousquet mining camps. Operating mines will also be visited: Francoeur, Pierre-Beauchemin, Ansil, Mobrun, Doyon and Bousquet. The delegates will be able to examine the main volcanic, plutonic and sedimentary rocks as well as the various structural features in this part of the Abitibi. Ore deposits will include both massive sulphide and gold deposits. The various geological and structural environments of these deposits will also be examined.
The southern part of the Abitibi Belt in Quebec is dominated by a prominent deformation corridor, the Cadillac-Larder Lake Fault Zone. This zone is oriented E-W and separates a volcanic domain in the north from an essentially sedimentary domain in the south. This sedimentary domain, comprising clastic rocks and various granitic complexes, belongs to the Pontiac Subprovince. The volcanic domain is composed of various “blocks” of volcanic assemblages intruded by granitic masses, separated from one another by fault zones, discordances and inear sedimentary units. On the regional scale, the imbricated volcanic “blocks” are lozenge-shaped, with E-W orientd long axes. In most cases, the relationships between these volcanic and sedimentary “blocks” remain ambiguous.