COPPER DIVISION: Gasp Smelter

Gasp is Noranda’s smallest copper smelter, but is well located.

The copper mining and smelting operations started up in 1955, at the company-built town of Murdochville in the Gasp region of eastern Quebec. The ore reserves were mined out over 45 years, and the mines and concentrator finally closed last October, leaving the smelter as a custom operation.

Custom work was not new to the smelter, which has been importing some of its concentrate since 1957, but improvements were needed. A $35-million modernization program since 1991 has resulted in a lower-cost, higher capacity plant able to treat mine concentrate as well as copper scrap and secondary materials, and with lower sulphur emissions.

The employees had eight years of notice before the mine closure, which cut the workforce from 632 the end of 1997 to about 300 today.

Old Metallurgy With a New Twist

CMJ toured the smelter with metallurgist Christian Bouchard in April of this year, to find out how the transition is going.

Gasp still has a reverberatory furnace, which is described as “old metallurgy” by Bertin Langlois, superintendent of business and development. The copper sulphide concentrate feed is smelted with flux to form matte in the reverb furnace.

The molten matte is tapped and poured into Pierce-Smith converters into which air and oxygen are injected to reduce the copper to 99% pure blister copper. This is refined in the anode furnace and then cast to form copper anodes, ready for shipment to the CCR refinery.

The slag from the converters returns to the reverb furnace to capture any remaining copper, and the furnace slag goes to the slag dump. Sulphur given off in the converters is captured and sent to the acid plant for fixation, while sulphur from the reverb furnace is released to atmosphere via the stack. Electrostatic precipitators collect dust from the reverb furnace and the converters, keeping the particulate emissions within the regulatory limits.

Originally Gasp had two small converters. The major part of the recent modernization program was the construction in 1998 of a third, larger, higher-performance Pierce-Smith converter at a cost of $18 million. Now 40% of the concentrate feed bypasses the reverb furnace and goes to a fluid bed drier, then to the new converter via the injection system. From here, all sulphur off-gasses can be captured. “This is a big asset for us,” says Langlois. “The new vessel has the flexibility to eventually be operated as a reactor.”

The other major parts of the upgrade were a $10.5-million oxygen injection system for the converters, and increased on-site oxygen-generating capacity. These expenses have resulted in a 50% increase in the concentrate capacity and a 66% increase in the scrap and secondary materials capacity. The anode production capacity has increased by 115%. Acid production capacity is up by more than 70%.

Transportation is a big part of the costs. Most of the concentrate arrives by ship at Sandy Beach near the town of Gasp. From there it is trucked 100 km to Murdochville. Anodes from the smelter are trucked to Gasp in transit to Noranda’s CCR refinery in Montreal East. About one-third go via rail, and the rest are taken by truck. The acid is trucked to Sandy Beach and then transported by ship.

Cleaning Up Its Act

As part of a major expansion initiative in 1973, Noranda installed a sulphuric acid plant and a dust recovery system to reduce SO2 gases and control dust emissions. This greatly improved the environmental scorecard at Gasp. To protect the residents from further lead contamination, the company voluntarily removed and replaced all topsoil in Murdochville nine years ago at a cost of $5 million. The company meets regularly with a citizens’ committee to review issues and discuss new initiatives. There have been no reported elevated blood lead levels in children in more than five years.

The most recent expansion has also improved environmental performance, increasing sulphur fixation from 60% a decade ago to 80-82% now. However, leading smelters today fix 90%-99% of their sulphur. “We are developing with that in mind,” says Langlois, “to be in range with the best smelters in the world in productivity, environment and cost.”

Gasp is not there yet. The lost-time incidents in 1999 were almost double the objective of 5.6 per 200,000 hours worked.

Says Langlois: “As long as we prove that we can be a viable, competitive operation, hopefully Noranda will always look on Gasp as a valuable asset, and continue to develop it.”