Within recent years portable seismic refraction units have found their place in the industry for shallow investigations. Completely portable, relatively inexpensive and of proven accuracy, the portable refraction seismograph is an electronic tool in an electronic age. The seismic refraction theory is based on the ability of various materials to transfer shock waves at different … Read more
It is truly remarkable how the image of longwall as a method of mining has changed. Today the world looks on longwall in the hope that it can produce the next really big break through in productivity. Three correlated machinery developments have made this possible, but it is not only the machinery developments, interesting though … Read more
Fly ash is extremely variable and heterogeneous in all respects except its fine size. Because of its production in huge quantities, it becomes significant as a potential raw material. Fly ash is a finely-divided, widely variable, heterogeneous material most of which is formed by the solidification of molten droplets of inorganic substances in the cooler … Read more
From time to time since the initial installation of an experimental flotation section in 1940, Permanente Cement Company has made efforts to beneficiate the low-grade limestone fraction which occurs in its deposit at Permanente, California. Limestone and the Reason for Its Beneficiation The Permanente deposit is a sheet of Calera limestone over 700 feet thick … Read more
A nickel-copper sulphide concentrate was treated in a pilot plant at Warren Spring Laboratory during 1961, by a hydrometallurgical roast-leach-solvent extraction process devised to cleanly separate the metal values, and produce acid sulphate liquors containing the metals. It is shown that 86 percent of the nickel and 95 percent of the copper could be leached … Read more
The author describes the actual processing of the government stockpile of chromiferous sands located at COQUILLE, OREGON, during 1955 and 1956. A general history of the stockpile is given, along with a background of the geology and origin of these sands. The flow sheet used in this operation is outlined in detail, and the minerals … Read more