MINING:
MIM mining activities include the production of lead and zinc concentrates as well as bulk and mixed concentrates. MIM use some of the most advanced mining and mineral recovery technology in the world. Exploration and involvement in new mines is an essential facet of the business. The most important MIM concentrates for use at Britannia Zinc limited are MIM bulk and McArthur River Mine concentrates.



CONCENTRATES:
Although MIM has its own mines, BZL is a 'custom' smelter. That means materials are purchased from all around the world by the ore-buying Raw Materials section. Some 320,000 tonnes of input material are brought from Australia, South America, Canada, Alaska, Iran, Scandinavia and Southern Ireland to Avonmouth, each year.



SHIPMENT OF INPUT ORES AND SECONDARY MATERIALS:
Concentrates and secondary materials are shipped direct to the ports of Avonmouth or Newport, and sometimes via Antwerp. Thus the smelter's proximity to the port of Bristol has been a feature since smelting began at Avonmouth in the 1920's. A conveyor, approx. 1 km in length is capable, with docks cranes, of discharging concentrates at the rate of 600 tonnes/hr. into the green ore store. This store has a capacity of 50,000 tonnes under cover. Zinc residues and pelletised steel plant flue dusts are also incorporated into the sinter feed mix, thus making BZL environmentally friendly, as a consumer of recycled materials.
As the prime energy source for the blast furnace operation, BZL consumes some 130,000 tpyes of cokes. Coking coals are imported into Portbury Dock, Bristol and other docks in South Wales.

THE PROCESSING OF CONCENTRATES INTO METALS::
The Avonmouth smelter was first based on the Horizontal Distillation process for the manufacture of zinc (operated 1920 - 1958). This process was superseded by the New Jersey, vertical Retort process (operated 1930's - 1971). Early experiments to develop a zinc blast furnace commenced in 1943 and by the early 50's No.1 and No.2 pilot plants were operating. No.1 was closed down in 1959. No.3 Imperial Smelting furnace was built and operated in Swansea Vale (operated 1960 - 1971). No.2 pilot plant ceased operations in November 1967. The existing furnace at BZL, Avonmouth, was commissioned in December 1967 and is the largest furnace of it's type in the world. The technology of simultaneously smelting lead and zinc, developed at Avonmouth is used in Australia, Zambia, France, Germany, Romania, Japan, Canada, Poland, Sardinia, Macedonia, China and India, under license to RTZ.