text: The generally recognized first successful commercial flotation process for mineral sulphides was invented by Frank Elmore who worked on the development with his brother, Stanley. The Glasdir copper mine at Llanelltyd, near Dolgellau in North Wales was bought in 1896 by the Elmore brothers in conjunction with their father, William. In 1897, the Elmore brothers installed the worlds first industrial-size commercial flotation process for mineral beneficiation at the Glasdir mine. The process was not froth flotation but used oil to agglomerate (make balls of) pulverised sulphides and buoy them to the surface, and was patented in 1898 (revised 1901). The operation and process was described in the April 25, 1900 Transactions of the Institution of Mining and Metallurgy of England, which was reprinted with comment, June 23, 1900, in the Engineering and Mining Journal', New York City. By this time they had recognized the importance of air bubbles in assisting the oil to carry away the mineral particles. As modifications were made to improve the process, it became a success with base metal ores from Norway to Australia.
  The Elmores had formed a company known as the Ore Concentration Syndicate Ltd to promote the commercial use of the process worldwide. In 1900, Charles Butters of Berkeley, California, acquired American rights to the Elmore process after seeing a demonstration at Llanelltyd, Wales. Butters, an expert on the cyanide process, built an Elmore process plant in the basement of the Dooley Building, Salt Lake City, and tested the oil process on gold ores throughout the region and tested the tailings of the Mammoth gold mill, Tintic district, Utah, but without success. Because of Butters' reputation and the news of his failure, as well as the unsuccessful attempt at the LeRoi gold mine at Rossland, B. C., the Elmore process was all but ignored in North America.
  Developments elsewhere, particularly in Broken Hill, Australia by Minerals Separation, Limited, led to decades of hard-fought legal battles and litigations for the Elmores who, ultimately, lost as the Elmore process was superseded by more advanced techniques. Another flotation process was independently invented in 1901 in Australia by Charles Vincent Potter and by Guillaume Daniel Delprat around the same time.
   Potter was a brewer of beer, as well as a chemist, and was likely inspired by the way beer froth lifted up sediment in the beer. This process did not use oil, but relied upon flotation by the generation of gas formed by the introduction of acid into the pulp. In 1903, Potter sued Delprat, then general manager of BHP, for patent infringement. He lost the case for reasons of utility, with Delpat arguing that while Delprats process, which used sulphuric acid to generate the bubbles in the process, was not as useful as Delprats process, which used salt cake. Despite this, after the case was over BHP began using sulphuric acid for its flotation process.
  In 1902, Froment combined oil and gaseous flotation using a modification of the Potter-Delprat process. During the first decade of the twentieth century, Broken Hill became the center of innovation leading to the perfection of the froth flotation process by many technologists there borrowing from each other and building on these first successes.
  Yet another process was developed in 1902 by Arthur C. Cattermole, who emulsified the pulp with a small quantity of oil, subjected it to violent agitation, and then slow stirring which coagulated the target minerals into nodules which were separated from the pulp by gravity. The Minerals Separation Ltd., formed in Britain in 1903 to acquire the Cattermole patent, found that it proved unsuccessful. Metallurgists on the staff continued to test and combine other discoveries to patent in 1905 their process, called the Sulman-Picard-Ballot process after company officers and patentees. The process proved successful at their Central Block plant, Broken Hill that year. Significant in their "agitation froth flotation" process was the use of less than 1% oil and an agitation step that created small bubbles, which provided more surface to capture the metal and float into a froth at the surface. Useful work was done by Leslie Bradford at Port Pirie and by William Piper, Sir Herbert Gepp and Auguste de Bavay.
  Mineral Separation also bought other patents to consolidate ownership of any potential conflicting rights to the flotation process - except for the Elmore patents. In 1910, when the Zinc Corporation replaced its Elmore process with the Minerals Separation (Sulman-Picard-Ballot) froth flotation process at its Broken Hill plant, the primacy of the Minerals Separation over other process contenders was assured. Henry Livingston Sulman was later recognized by his peers in his election as President of the (British) Institution of Mining and Metallurgy, which also awarded him its gold medal.