With the S-6 screen’s bigger capacity, System II’s production is said to be outstanding using either jaw crusher heading the system. The screen can more than handle what it is being fed. To illustrate, the bigger jaw crusher’s throughput rate is 450 to 550 tons per hour and the smaller jaw crusher’s throughput rate is 450 to 500 tons per hour. The crushing rates fluctuate depending on what ratio of rock to sand is fed the jaw crusher. Crushed rock fed into the Extec X44 SBS cone crusher from the screen is 2 to 6 inches, which is in turn reduced to 2-inch minus. The throughput for that cone crusher is 200 to 250 tons per hour, and the screened-products throughput delivers 450 to 550 tons per hour, which include a 2-inch minus aggregate and 1/4-inch sand.

The System I throughput is not as high because the cone crusher production is only 100 to 140 tons per hour, even though the crushed rock fed it is 5-inch minus instead of the 6-inch minus fed the cone crusher in System II. “The reason we feed a smaller size rock to the [System I] cone is that the throughput rate was too low when feeding it 6-inch minus,” Mains says.

Despite, the bottleneck of the smaller cone in System I, it has a finished-products throughput ranging from 250 to 300 tons per hour. The Extec S-5 screen throughput of 375 to 475 tons per hour is fed from the jaw crusher crushed rock and the recirculated crushed rock fed from the cone crusher.

According to Taylor, the portable crushing and screening equipment used at the quarry has been quite satisfactory, although he says he prefers the quality service he receives from the Extec dealer, Extec Eastern of Trainer, Pa. “All the equipment has been performing well, but the services we receive from Extec Eastern have been outstanding. We will continue our business relationship with Extec Eastern because of the services experienced and their products,” he says. “We lose practically no production downtime using Extec equipment because the dealer responds immediately to any plant issues. The high-quality services offered by this company are as important to us as the quality product it is selling.”

Rodney Garrett, a freelance journalist and photographer, specializes in the construction and mining industries.