Letters: Sherritt Overlooked

The article “the refractory Riddle,” in your August, 1990 issue, was a very comprehensive compilation of information on the subject of recovering gold from arsenopyrite . . . Or was it?

One point not considered was the strenuous and often critical steps that led to the development of a novel process using hydrometallurgical means as opposed to the pyrometallurgical process of roasting that was traditionally used.

More than 35 years ago, Sherritt Gordon was established as a pioneer in pressure hydrometallurgy to recover nickel and cobalt from sulphides in autoclaves at Fort Saskatchewan, Alta. However, the research and devlopment work did not stop there, and pressure leaching or oxidation was extended to the recovery of other metals, like zinc and gold.

PROCESS

DEVELOPMENT

IS BEING STUDIED

FOR SEVERAL PROJECTS

Due to market conditions, pressure oxidation of refractory high-grade sulphide gold ores only became economical in the 1980s. Sherritt Gordon conducted the process development and provided process engineering in 1984 for the design of the first commercial application of pressure oxidation to refractory gold concentrates. The Sao Bento plant, in Brazil, was built under Sherritt’s license and started up in 1986.

In the same period, Sherritt did the process development study and process engineering for Placer Dome’s Porgera joint-venture project in Papua New Guinea. The plant is being built under licence and should start up in the summer of 1991. In 1987, Sherritt conducted the studies for applying pressure oxidation to the Melba project in Greece and to RTZ’s Lihir joint-venture project in Papua, New Guinea. Both plants will operate under Sherritt Gordon’s licence.

In 1989, Sherritt completed the process development study and piloted the process for Placer Dome’s Campbell mine. The metallurgical work, including both the laboratory and pilot plant, was done in Sherritt Gordon’s Research Centre, in Fort Saskatchewan, Alta. Sherritt has granted licence to Placer to operate the plant, which Sherritt Gordon is currently engaged in process development studies for several refractory gold projects in North America and other parts of the world. In all of these cases, pressure oxidation is being considered for its inherent environmental advantages.

Nestor Torres,

Technology Marketing Co-ordinator,

Sherritt Gordon Ltd.

What About Nickel?

In the article “metals in review,” in your November, 1990 issue, the inventory data are presented in terms of weeks of consumption for most metals except for nickel, in which case a relative increase of the inventory tonnage is offered. This is unfortunate, as the data cannot be compared with the data published for other commodities.

I would appreciate, and I’m quite convinced other specialists working in the fields of metal mining and exploration would also, if an absolute value (for instance in week-consumption-units) could be released for nickel as well.

Richard Dahl,

Consulting Geologist, Geomines,

Montreal, Que.

Editor’s Note: The author of the article, metals analyst Julian Baldry, tells us that nickel inventory recently was equivalent to 5.8 weeks of consumption. (See graph below.)

Whose Rabbit?

A photo caption on page 16 of the October, 1990 issue identified Eldorado Nuclear as the owner of the Rabbit Lake uranium mine. This is not correct. The Rabbit Lake operation is now owned by Cameco (66.67%) and Uranerz Exploration and Mining (33.33%). The operator is Cameco.

Elaine Kergoat,

Publications Specialist, Cameco,

Saskatoon, Sask.

Correction

Allan Este, author of “internal Responsibility” in the Managing column of our December issue, is president of Estonix International, not Estonics.