The Mount Lyell Mine’s smelters were famous throughout the world as the first to achieve complete or absolute pyritic smelting which enabled the separation of copper from sulphide rich ore without the use of any additional fuel. The smelters also produced plumes of sulphur rich gases that covered Queenstown and the surrounding country and contributing to the destruction much of the landscape.
The early success of the Mt Lyell Company was based on the development of the pyritic smelting process by Robert Sticht, the mine’s Chief Metallurgist and then first General Manager. Construction of the copper smelters began in 1895 and the first attempt at smelting using the pyritic technique on June 25th 1896 was successful.
By 1899 eleven furnaces were in operation. As well six Bessemer converters had been installed to further refine the copper produced by the Smelters so that by the end of that year the company was exporting 750 tons of copper a month.
Continuing development of the smelting process saw the company’s smelters became in 1902 the first in the world to successfully use the absolute pyritic smelting technique.
In 1904 soon after the achievement of complete pyritic smelting a comprehensive description of the Mt Lyell mine’s smelting process was included in the publication “Australian Mining & Metallurgy” by Donald Clark. This detailed report also includes numerous engineering drawings of the mine’s ore processing plant.
Pyritic smelting continued to be used until 1922 and was responsible for the massive plumes of sulphur rich fumes released into atmosphere from the smelter stacks. It was also responsible for the production of large quantities of slag that are still a feature of the mine site.
As a result of the lower grade of ore being mine in 1922 the direct smelting process was changed with the installation of a wet concentration or flotation plant. This concentrated the ore before it was smelted.
A few years later in 1928 an electrolytic refinery using the cheap electricity produced by the Lake Margaret hydro-electric scheme was installed so that high quality copper could be produced. These copper cathodes produced by electrolytic refining averaged 99.97% copper compared to the 99.2% copper produced by the Bessemer converters.
The electrolytic refinery was closed down in 1964 and the smelters in 1969 as they were no longer able to compete economically. However, the production of copper concentrate using much improved flotation and filtration process continues today.
Pyritic Smeling
Pyritic smelting is a process of smelting that requires little or no fuel to separate metal from the ore by using the heat resulting from the combustion of the sulphur rich ores – basically the ore becomes a source of fuel for smelting the metal contained within the ore. |
