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 world's 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.