Historical Note: Minerals Separation Ltd


In the first five years of the twentieth century, Minerals Separation Ltd, a small London-based company, was involved in developing a revolutionary technique of ore extraction. Its work, along with that of others, emerged in response to 'the Sulphide Problem', seen by some historians as the most serious metallurgical crisis faced by any Australian mining field in the nineteenth century. Essentially the problem was that companies involved in mining silver, lead and zinc found that the deeper they mined the lode, the more difficult these metals were to extract and separate. The ore closer to the top of the lode was oxidised, and as such was easily smelted. In the deeper sections of the lode however, the minerals sought-after existed in sulphide form and there did not exist a method of extraction and separation that could be used economically. The deeper a lode was mined, the further diminished the percentage of useable ore. At many mine sites, piles of tailings grew higher and higher, loaded with seemingly irretrievable precious metals. The imperative to solve this problem - to somehow unlock these metals from the piles of worthless rock - was established.

Methods of separation using the specific gravity of each metal were tried but largely failed. Magnetic separation was tried but proved uneconomical. In 1900, the method of flotation as a means of separation emerged. This involved mixing water and chemicals with the ore so that certain mineral particles floated to the top and could be skimmed off easily. The original patents for the flotation process were secured by C. V. Potter in 1901 and by G. D. Delprat in 1902. Controversy over the originality of each soon followed and litigation ensued, lasting until 1907. The Potter - Delprat process, as it was referred to after 1907, proved unsuccessful on a large scale. In 1905, Minerals Separation Ltd improved the process in two ways. Firstly, by the addition of a small quantity of oil to the pulp and secondly by producing violent aeration via the mechanical agitation of the mixture. In this way they were able to separate the valuable material from the tailings. This process of Froth Flotation became the hallmark of Mineral Separation Ltd and constituted a major revolution in minerals technology. In 1905, this process was adopted at Broken Hill and effectively solved the problem of recovering the precious minerals from the tailing dumps.

All was not solved, however, for two problems persisted. Froth flotation was still unable to separate zinc from silver-lead conglomerates. Thus when the process was applied to newly-mined ore, unseparated concentrations of lead and zinc were produced. This lead to further developments in the Mineral Separation Process. F. J. Lyster (Zinc Corporation), T. M. Owen (Junction North) and Leslie Bradford (B.H.P) all made patentable improvements to the process at the mine sites themselves. These developments, in the direction of 'selective flotation', proved very successful.

Another player in the game was the Belgium-born chemist, Auguste De Bavay. In July 1906 he patented his 'skin' or 'film' flotation process and opened what was to become a successful plant at Broken Hill. In 1909, De Bavay started the public company, Amalgamated Zinc (De Bavay's Ltd), and enlarged the plant at Broken Hill. The sole business of companies like Amalgamated Zinc and the Zinc Corporation was to use the flotation process on the materials from the tailings dumps.

At some stage between 1910 and 1912, Minerals Separation Limited obtained the license to use De Bavay's Sulphide Process of ore extraction. It appears they actively traded patents, assayed ore samples at their South Melbourne flotation plant and installed their own plant and processes at clients' mine sites under license. A number of metallurgists were employed by the company; H. Lowrey, H. Lavers, C. Faul, J. R. Godfrey, H. L. Jene. Their reports and assays are contained in their files.

Minerals Separation Ltd

United Kingdom Head Office: 62 London Wall, London, E.C.
Melbourne Agents: Gibbs Bright and Co., 34 Queen Street.
General Manager for Australia: H. Howard Greenway.
[See File 92, 20 April 1910]

Minerals Separation and De Bavay's Processes Australia Pty Ltd

Melbourne address: Collins House, Collins Street.
Secretary: Edward H. Shackell
[See File 100, 29 June 1912]

Historical references:

Blainey, G., The Rise of Broken Hill, (Macmillan of Australia, 1968)
Carroll, B., Built on Silver: A History of Broken Hill South, (Hill of Content, 1986)
Notes on the Minerals Separation Collection by Peter Crabb and from the collection itself.
Published by the Australian Science and Technology Heritage Centre on AustehcWeb, April 2004
With support from Peter Crabb and The University of Melbourne
Listed by Mark Scillio and Gavan McCarthy with Tim Sherratt
HTML edition Ailie Smith
Updated 9 November 2007
http://www.austehc.unimelb.edu.au/guides/mine/historicalnote.htm

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