Aggregates Manager Digital Magazine
Issue link: http://read.dmtmag.com/i/777939
18 AGGREGATES MANAGER / February 2017 PLANT PROFILE use gyratory crushers. Because of varying flows of material coming from the primary, a bin is used to regulate the feed to the rest of the circuit to prevent any surges. "Everything is automated, including the scales and sampling points," Grashel notes. "We have one guy in the primary, one guy in the tower who operates the dry circuit, a series of ground personnel, and maintenance men who float around. We operate roughly 5 miles of conveyor, including ship loading and everything from end to end." The dry circuit is a fractionated plant that produces three main products — 4x2, which is made to order as needed, and 2x0 and 1x0, which are either sent direct- ly to the vessels at the dock or used as a blend for the next plant. The "Hill line," as they call it, carries material to the next processing plant or load out surge. "The stacker does double duty — everything on the right goes straight to the ships, and everything on the left is surge for the wash plant," Grashel explains. "There are four 1961 vintage overhead galleries leftover from the 1960's plant. They can hold upwards of 80,000-plus tons of product. We still use three of the four today." The wash plant separates fractions, producing 2x1, 1x1/2, 1/2x1/4, and man- ufactured sand. All of the products are placed in stockpiles over tunnels so that blends can be created. Everything going out to the vessels is tested at the quality control lab, where personnel do manual cuts and quick gradations every thousand tons, making adjustments as needed as they load the vessels. Lab personnel are in constant communication with loader operators and the shuttle operators feeding the vessel. The conveyor that feeds the dock's boat loadout area crosses the main road in the Village of Marblehead, which has a full-time population of approximately 1,000 and a summertime population that soars because of tourists. The conveyor is enclosed where it passes over the road and has the name of the quarry operation on its side. Mainly river-class boats are loaded at the loadout facility. "They berth on the west side and shift up and down along the dock as we load it," Grashel says. "There's someone in the tower who is communicat- ing with the lab technician checking the samples, loader operators back in the plant, and a mate on the vessel. "We usually load one vessel a day, which can take anywhere from 10 to 12 hours, depending on products and shifts. The average size load is 17,000 tons; for the occasional larger freighters it is upwards of 30,000 tons. We can also load smaller barges that go to the islands, and Because of varying flows of material coming from the primary, a bin is used to regulate the feed to the rest of the circuit to prevent any surges. The dry circuit is a fractionated plant that produces three main products, which are either sent directly to the vessels at the dock or used as a blend for the next plant.