1880-1930: the golden years of mineral processing technology

The period from 1880 to 1930 saw significant developments in mineral processing technology. These developments were closely related to changes in the nature and amount of energy available: The transition was made from human and animal power, first to steam and later to electricity. The first significant developments were in comminution. Beginning in 1876, tumbling mills were introduced, and classification devices incorporated in grinding circuits. At about the same time, jigs were introduced for concentration, and flotation of graphite was implemented. In the 1890s, cyanidation and zinc precipitation were developed for recovery of gold and silver, and the Wilfley table was introduced. Finally, in about 1902, flotation of sulfide minerals was developed, first at Broken Hill in Australia, and then at numerous copper mines. The 1920s and 30s were a period of intense technological development in froth flotation. In the 40s, plants got larger, but there was little change in equipment. Then in the 1950s, autogenous grinding spread beyond the Rand, and hydrocyclones, flotation columns and online analysis were introduced. All equipment got larger in the 1960s, and semi-autogenous mills were introduced in 1970s.