the mattabi mine, a volcanogenic massive sulfide deposit located 60 km north of ignace ontario, in the archean superior province, produced 13.5 mt of ore with an average grade 7.5% zn, 0.88% cu, 0.77% pb and 3.10 oz/t ag in the period 1970-1983. preliminary studies indicated the presence of an especially varied mineral assemblage, which was studied in detail. as well as chalcopyrite and sphalerite, the deposit contains abundant galena accounting for its unusual lead production. argentian tetrahedrite, or frelbergite, is also abundant, and in the absence of native silver and acanthite, is clearly a major carrier of silver. [...]