The process makes smelting more energy efficient and is today used for 50% of the world's primary copper production.

Of this, £450,000 was due to copper production between 1740 and 1777.

The group produces and markets all other important elements of the copper production as specialty products.

The copper production flourished in 1914 when the factory employed more than 200 workers.

Present worldwide copper production is near 15 million tons per year.

After the sale, copper production will account for about 11 percent of the company's sales, compared with the current 25 percent.

The potential annual copper production has been estimated to be 900,000 to 2.2 million tons.

In addition to lead and cotton, copper production was of great importance.

Construction continues, with mechanical completion and copper production targeted for early 2014.

With so many problems plaguing the industry, copper production is running below consumption for the third straight year.