Хонинговальные головки

Figure 9.2a shows the Dorr classifier as it was in 1940, and it has changed little since then. Mineral companies quickly accepted the rake classifier and thickener, and closed — circuit wet grinding became part of mineral processing technology. With its reciprocating rakes, the Dorr classifier soon had competition from the Akins classifier (Figure 9.2b), […]

By 1900, rock drilling had reached the point at which hammer drills were available that operated at several hundred cycles per minute, worked at any angle of inclination, had the cutting head held at the rock face by an air cylinder, and had the chips and fine detri­tus continually removed from the working zone by […]

Although John Bennett had a flair for mathematics at school, he did not take the scholar­ship he won to Oxford University. Instead, when World War I started, he joined the Royal Engineers at the age of 17. After the war he lived in Turkey and Greece for 15 years, where he worked as a diplomat […]

Until the 15th century, all the major developments in size reduction were for the food preparation industry—for the grinding of grain to make flour. Although there were demands for minerals, particularly gold, copper, zinc, and lead, and for construction materials, the demands were small, and the methods used to grind grain were adequate. When manually […]

The 20th century ended with the mining and stone industries using the same types of primary crushers that were invented by Blake and Gates and used at the end of the 19th FIGURE 5.24 Typical size-reduction circuit for a cryogenic scrap tire-processing plant (Reschner 2002; reprinted by permission from Recovery Technologies Ltd.) TABLE 5.2 Sizing […]

The background to the flotation process was similar to that for the cyanide process. The reserves of ores containing coarse-grained minerals were dwindling, and ores containing fine-grained minerals—which were difficult to extract by the processes of the time— needed to be mined. The cyanide process was unsuitable for ores containing lead, zinc, and copper, all […]

With the success of primary autogenous milling and feed control at Union Corporation, primary autogenous mills became an accepted feature of Rand grinding practice. The autogenous mill circuits required about 25% more power than conventional circuits using pebble mills, but the smaller crushing circuit meant that there was lower capital investment and reduced maintenance cost. […]

The history of cyclones goes back to 1891 when E. Bretney obtained the first patent (Bretney 1891). The Bretney cyclone was designed with a closed apex for intermittent discharge and was the forerunner to present-day desanders that are used for separating sand from water in pressurized water systems. The Bretney cyclone had a roof entry […]

Advances in drilling and blasting were always hard won, and the work was onerous and dangerous until well into the 20th century. Objectives of blasting during the 20th cen­tury were ■ Before 1960: to make excavation possible ■ 1960-2000: to make excavation efficient ■ After 2000: as part of the overall rock breakage process Much […]

Born in New Jersey in 1872, John Van Nostrand Dorr started work as a laboratory assis­tant in Thomas Edison’s laboratory in Orange, New Jersey, at the age of 16. At the time Edison had become heavily involved in mining and processing low-grade magnetite ores. Thinking that the iron ore deposits in the eastern United States […]