Garpenberg: an old concentrator at peak performance.

The Swedish deposit, mined since the 13th century, has sulphide ores grading 160 g/t Ag, 4.2% Zn, 2.3% Pb, 0.1% Cu and 0.5 g/t Au. Ore minerals are chalcopyrite, galena and sphalerite with small amounts of pyrite, pyrrhotite, freibergite, tetrahedrite, amalgam, talc and Mn in sphalerite, silicate gangue and alabandite. Ore feed from the Norra mine has increased in the last few years. Throughput is slightly more than 1 000 000 tonnes/a. Fully autogenous grinding was introduced in 1989, allowing the hard ore from Norra and the soft Garpenberg ore to be processed together. A brief survey is given of developments since then in primary grinding, gravimetric separation, copper-lead flotation, zinc flotation, dewatering and tailings disposal; a number of investigations that proved dead-ends are also mentioned. Annual concentrate grades and recoveries from 1989 to 2002 are presented.
The Swedish deposit, mined since the 13th century, has sulphide ores grading 160 g/t Ag, 4.2% Zn, 2.3% Pb, 0.1% Cu and 0.5 g/t Au. Ore minerals are chalcopyrite, galena and sphalerite with small amounts of pyrite, pyrrhotite, freibergite, tetrahedrite, amalgam, talc and Mn in sphalerite, silicate gangue and alabandite. Ore feed from the Norra mine has increased in the last few years. Throughput is slightly more than 1 000 000 tonnes/a. Fully autogenous grinding was introduced in 1989, allowing the hard ore from Norra and the soft Garpenberg ore to be processed together. A brief survey is given of developments since then in primary grinding, gravimetric separation, copper-lead flotation, zinc flotation, dewatering and tailings disposal; a number of investigations that proved dead-ends are also mentioned. Annual concentrate grades and recoveries from 1989 to 2002 are presented.