text: Developments in the United States had been less than spectacular. Butterss failures, as well as others, was followed after 1904, with Scotsman Stanley MacQuistens process (a surface tension based method), which was developed with a modicum of success in Nevada and Idaho, but this would not work when slimes were present, a major fault. Henry E. Wood of Denver had developed his flotation process along the same lines in 1907, patented 1911, with some success on molybdenum ores. For the most part, however, these were isolated attempts without fanfare for what can only be called marginal successes.
  In 1911, James M. Hyde, a former employee of Minerals Separation, Ltd., modified the Minerals Separation process and installed a test plant in the Butte and Superior Mill in Basin, Montana, the first such installation in the USA. In 1912, he designed the Butte & Superior zinc works, Butte, Montana, the first great flotation plant in America. Minerals Separation, Ltd., which had set up an office in San Francisco, sued Hyde for infringement as well as the Butte & Superior company, both cases were eventually won by the firm in the U. S. Supreme Court. Daniel Cowan Jackling and partners, who controlled Butte & Superior, also refuted the Minerals Separation patent and funded the ensuing legal battles that lasted over a decade. They - Utah Copper (Kennecott), Nevada Consolidated, Chino Copper, Ray Con and other Jackling firms - eventually settled, in 1922, paying a substantial fee for licenses to use the Minerals Separation process. One unfortunate result of the dispute was professional divisiveness among the mining engineering community for a generation.
  In 1913, the Minerals Separation paid for a test plant for the Inspiration Copper Company at Miami, Arizona. Built under the San Francisco office director, Edward Nutter, it proved a success. Inspiration engineer L. D. Ricketts ripped out a gravity concentration mill and replaced it with the Minerals Separation process, the first major use of the process at an American copper mine. A major holder of Inspiration stock were men who controlled the great Anaconda mine of Butte. They immediately followed the Inspiration success to build a Minerals Separation licensed plant at Butte, in 1915–1916, a major statement about the final acceptance of the Minerals Separation patented process.
  John M. Callow, of General Engineering of Salt Lake City, had followed flotation from technical papers and the introduction in both the Butte and Superior Mill, and at Inspiration Copper in Arizona and determined that mechanical agitation was a drawback to the existing technology. Introducing a porous brick with compressed air, and a mechanical stirring mechanism, Callow applied for a patent in 1914 (some say that Callow, a Jackling partisan, invented his cell as a means to avoid paying royalties to Minerals Separation, which firms using his cell eventually were forced to do by the courts). This method, known as Pneumatic Flotation, was recognized as an alternative to the Minerals Separation process of flotation concentration. The American Institute of Mining Engineers presented Callow the James Douglas Gold Medal in 1926 for his contributions to the field of flotation. By that time, flotation technology was changing, especially with the discovery of the use of xanthates and other reagents, which made the Callow cell and his process obsolete.
  Montana Tech professor Antoine Marc Gaudin defined the early period of flotation as the mechanical phase while by the late 1910s it entered the chemical phase. Discoveries in reagents, especially the use of xanthates patented by Minerals Separations chemist Cornelius H. Keller, not so much increased the capture of minerals through the process as making it far more manageable in day-to-day operations. Minerals Separation's initial flotation patents ended 1923, and new ones for chemical processes gave it a significant position into the 1930s. During this period the company also developed and patented flotation processes for iron out of its Hibbing lab and of phosphate in its Florida lab. Another rapid phase of flotation process innovation did not occur until after 1960.
  In the 1960s the froth flotation technique was adapted for deinking recycled paper.
  The success of the process is evinced by the number of claimants as "discoverers" of flotation. In 1961, American engineers celebrated "50 years of flotation" and enshrined James Hyde and his Butte & Superior mill. In 1977, German engineers celebrated the "hundredth anniversary of flotation" based on the brothers Bessel patent of 1877. The historic Glasdir copper mine site advertises its tours in Wales as site of the "discovery of flotation" based upon the Elmore brothers work. Recent writers, because of the interest in celebrating women in science, champion Carrie Everson of Denver as mother of the process based on her 1885 patent. Omitted from this list are the engineers, metallurgists and chemists of Minerals Separation, Ltd., which, at least in the American and Australian courts, won control of froth flotation patents as well as right of claimant as discoverers of froth flotation. But, as historian Martin Lynch writes, "Mineral Separation would eventually prevail after taking the case to the US Supreme Court [and the House of Lords], and in so doing earned for itself the cordial detestation of many in the mining world."