On the Cover: Enon Sand and Gravel Buys Vertical Clamshell Dredge System
The bucket is an electro-hydraulic clamshell built by Supreme Manufacturing.
The dredge was re-named the Rocksand II. It has a 200-foot digging depth and capacity of 375 tons per hour. The system is expected to improve efficiency, reduce costs and increase the life of the pit more than 10 years, said Operations Manager Andy Haumesser.
The used vertical clamshell dredge was transported from the previous owner in Florida, and was in operation at Enon by the end of October, 2009. The crew sandblasted and re-painted the dredge, which will work in full view of a four-lane highway, but it needed little other repair or refurbishment, said Haumesser. At the time of purchase, Enon was finishing a two-year contract to provide asphalt aggregate for a 10-mile re-paving project on I-70 between Dayton and Columbus. The dredge was in operation in time to complete that project and to provide concrete aggregate for a new hospital complex in Springfield, Ohio. In mid-January, production had stopped due to weather but the company is prepared for startup of the dredging operation in the spring.
Enon produces concrete and asphalt aggregates, as well as base products.
The dredging system consists of the clamshell, onboard dewatering screens, crushers and breakers, and an extensive conveyor system to transport and stack the product on shore. The weight of the complete unit is approximately 345 tons, and the pontoon footprint is 94 by 43 feet. The digging well opening is 31 by 24 feet, and the trolley beam is 86 feet, six inches. A separate fine sand recovery is located on board, and a silt pump transports fines away from the digging area. This is one of the features that improves production.
A 1500 ft/lb Allied pedestal hydraulic impact hammer with a 21-foot reach is operated with the manual control valve console or from the remote joystick control mounted in the operator’s cabin.
Haumesser will present a talk on clamshell dredging of aggregates at the Agg1 conference in February, sharing the podium with Damon Gonzales of Dredging Supply Company, who will talk on hydraulic dredging of aggregates.