CONE CRUSHERS

Long ago stamp mills gave way to more refined crushing units. Today, there is a full range of primary and secondary crushing systems. Cone crushers for the mining industry are generally relegated to secondary or tertiary roles in crushing. But that doesn’t minimize their roles in turning mineralized rock into salable metals.

Nordberg

Nordberg-manufactured Symons cone crushers have been around a long time. In fact, the company’s first cone crusher, built 60 years ago, is still in active use. Symons offers both shorthead and standard cone crushers, the difference being that the shorthead, with its steeper head angle and more parallel crushing cavity, takes smaller feed and produces smaller product — in the range of 3/16 to one inch. Symons shortheads are offered in six sizes from two to seven feet in diameter and can produce up to 720 net tons per hour.

The standard crusher produces crushed product from 1/2 to 2 1/2 in both closed and open circuits. Six sizes are available from two to seven feet, and open circuit capacities range from 18 to more than 1,500 net tons per hour.

Special features include the Symons long force arm, which provides lower eccentric bearing loads, lower bearing temperatures, increased bearing life, and greater crushing force; large head capacity because of a larger displacement volume; complete accessibility from above the crusher; and a spring release system that provides safe, effective overload protection.

Nordberg also manufactures the Omnicone crusher with its lower headroom requirements (as compared with Symons models), its rapid transformation from a secondary standard to a tertiary shorthead, and hydraulic setting, clamping and clearing for finger-tip control.

Nordberg has also developed the MP1000, which draws up to 1,000 hp with about double the capacity of similiarly sized conventional cone crushers. The MP1000 can fit on a Symons 7-ft. foundation. This “breakthrough” technology, says Nordberg, has been field-proven in Papua New Guinea and at the El Teniente mine in Chile.

Boliden Allis

This company, through several predecessor firms, can trace its roots to at least 1878, when the first successful gyratory crusher was built in the U.S. Boliden Allis manufactures hydrocone crushers in sizes from 22 to 84 inches. The company emphasizes power in its promotional brochures, saying “horsepower is work, and it’s the only true measure of what a machine can produce in tons.”

Boliden Allis hydrocone crushers feature rugged, heavily ribbed top and bottom shells with thick cross-sections. Another advantage is the 2-bearing mainshaft support (spider and eccentric bushings). The thrust-bearing assembly is a 3-piece design.

Standard equipment on the crusher is the Hydroset Control, which permits refulation of the mainshaft and mantle position on-line. Setting changes can be made in seconds and under load. Pressure gauge and damper assembly provide operators with direct readouts of Hydroset control pressure and a quick reference to actual crushing stresses inside the machine. Optional automatic crusher regulation can, among other things, increase utilization of crusher power, eliminate the need for constant surveillance, promote product uniformity and increase liner life.

For more information on Boliden Allis’s Model 22, 36, 45, and 84-inch crushers and its Century Series crushers, contact the company at its Kirkland, Que., offices. Boliden Allis is a member of the Trelleborg Group.

Telsmith Gyrasphere

Telsmith’s crushers feature high-capacity rates, low-power requirements, low maintenance needs and high reduction ratios. They are available in standard (s) and fine crushing (fc) types, ranging from 24 to 66 inches. Portable and stationary installations are available.

Type s crushers are designed for coarse and intermediate crushing while the fc line is dedicated to fine, secondary and tertiary applications. Three models, the 245S, 367S and 6614S, have extra large receiving openings. A patented rotary seal converts reciprocating or gyratory motion into rotary motion.

Telsmith Gyraspheres also feature “cam-and-lever” design, fabricated steel main frame, manganese steel crushing members and spring overload relief for automatic protection and relief from tramp iron or packing.

A company brochure describes the cam and lever mechanism this way: A cam machined into the eccentric is supported by a roller bearing and transmits a wedging action through another roller bearing into the head. In conjunction with this cam, a lever action is imparted to the head and shaft from the eccentrically bored, tapered hole in the eccentric. These two forces working together carry the loads imparted by crushing, distributing crushing loads over a large area.

Bristol Machine works and P.R. Engineering are two companies involved in crusher refurbishing.