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The Rock of Gibraltar


The Silvi Group Took Over a New Jersey Quarry, Added New Processing Equipment, Automation and Fines Recovery, and Has a Long-Term Plan for Success.

By Mark S. Kuhar

Gibraltar Rock, Belle Mead, N.J., may be located five miles north of Princeton University, but quarry owner The Silvi Group looks like the educated one. The company acquired the 1,438-acre site in 2009 from 3M Corp., which once made roofing granules there. Silvi added a slew of new equipment and innovations. The quarry hasmore than 350 million tons of reserves. How is that for an advanced degree of success?

“The property is located right in the center of our ready mix activities, so we are our own biggest customer,” said company co-owner Larry Silvi. “The fact that the current deposit is a nice diabase trap rock and there is a rail line at the plant work in our favor. The deposit also contains a fair amount of argillite, a lighter form of trap rock which is permitted for mining as well.”

Gibraltar Rock is truly a full-line construction-materials producer. “We make the complete range of materials from jetty stone and rip rap all the way down to manufactured sand,” said Aidan Kilcoyne, plant manager. “But our primary focus is to make #57s for our ready mix plants.”

Production at the 1,000-tph quarry starts with drilling and blasting operations. Drilling services at the site are contracted out to C.S. Garber & Sons Inc., Boyertown, Pa. Blasting is conducted by Austin Powder Co. Glenn Mayberry is the company’s main blaster.

Great care is taken to alleviate community concerns about blasting. There are approximately 20 households that are notified personally by phone before each blast. Local fire and police, and also the township, are kept in the loop. Vibration and noise monitoring is conducted by Vibratech at several locations outside of the quarry property.

According to Uday Patankar, the company’s community relations and environmental vice president, all blasting information is shared with the state. “We believe in being proactive,” he said. “And we do our best to be good neighbors.”

Oversize material at the quarry face is hammered with a Caterpillar 345CL excavator fitted with an Atlas Copco secondary breaking hammer.

New Equipment
Taking over a new quarry meant investing in new processing equipment, and the company started at the quarry face with new loaders and haul trucks. “We bought brand new Caterpillar 992K and 980H loaders,” Silvi said. “We also bought two 773E and one 773B haul trucks.” The loaders and haul trucks work in pass match, cycling material between the quarry face and the primary.

The primary crusher is an Allis Chalmers 4265 Gyratory. It was rebuilt by the company when they took over, and is an efficient first step in their production process. From there the material is screened out by a triple-deck, 8- x 20-ft. Deister screen that makes a 6- to 8-in. rip rap and dense grade aggregate.

The remainder of the material is sent further along within the plant for crushing and screening. The oversize material off the Deister screen is fed into a rebuilt Nordberg 7-ft. standard cone crusher. From there the material is sent to two separate triple-deck, 8- x 20-ft. Deister screens outfitted with Polydeck screen panels.

Oversize from the screen decks is sent to a Symons 5-1/2-ft. short head cone crusher. The chutes and gates coming off the two separate Deister Screen decks allow the plant to make various products such as railroad ballast, #2 stone and more. The undersize material coming off the two Deister decks is sent on to a surge pile that feeds the tertiary plant.

Tertiary Time
The tertiary plant draws material from the surge pile mentioned above. The material is screened through an 8- x 24-ft., triple-deck Deister outfitted with spray nozzles for wet processing.

The oversize material is sent to a new Sandvik 660 cone crusher that was purchased specifically for the plant, and then returned to the Deister for re-screening. The undersize material off the Deister is sent to two double 44-in. Eagle Iron Works wash screw conveyors. The #57 material is stacked using a Thor T150-5 stacker.

Incorporating a manufactured sand plant allowed the company to take a low price point material and get greater value out of it. “Screenings sell for about two dollars-per-ton, but we can get much more for manufactured sand,” Silvi said. “We’re not in the asphalt business, but we are in the ready mix business, so it makes more sense economically for us.”

Automation
The company believes strongly in automation, and uses Baltimore-based Kruse Control’s Wonderware operations-management software. “We can run the primary and finish plant from one building with one operator,” Kilcoyne said. “From there he can see all of the control functions on the crushers and conveyors, and monitor the plant.”

The automation package also supplies trending information on the plant. “If there is an overload condition for instance, we can go back and see what lead to that,” Kilcoyne said. “It really has nice trouble-shooting capabilities.”

In the load-out phase, automation also plays a central role. Material is loaded onto customer trucks with two Caterpillar 980H wheel loaders. Also on-site is a Caterpillar 990F wheel loader, Case 580M backhoe and two Komatsu WA-700 loaders. Customer trucks then proceed to the scale.

“We are using a BMG Seltec package that allows us to have a fully unattended scale house,” Kilcoyne said. “Every driver that comes in serves himself, selects the product he wishes, loads up, and checks himself out. All information is instantly sent to our central dispatch at the main office for billing and accounting.”

According to Silvi, a secondary security procedure is in place at load-out. A camera system takes a picture of the truck driver, and the license plate of his vehicle. A second system of cameras allows management to monitor activity all over the quarry from the main office.

While the quarry is now operating at high efficiency, the company is not done tweaking production. “We’re still ramping up,” Silvi said. “In the next phase we plan to widen the hole and start moving into some of our additional reserves, which will give the quarry a bigger footprint.”

Although the plan to expand the quarry is further up the road, they are thinking now about the new haul roads they will need to access the additional reserves. “We are already moving in that direction,” Silvi said.


The Silvi Group

The Silvi Group Companies is a family owned business that was founded in 1948 by Larry Silvi Sr. A grocer by trade, he accepted possession of a rundown block plant to satisfy a debt. Shortly thereafter, William J. Levitt (then the world’s largest home builder) began to construct one of his large and affordable communities (Pennsylvania’s “Levittown”) next to Silvi’s block plant. Larry Sr. struck a deal to supply the project and was off to the races.

Thirty-five years later, his sons John and Larry took the reins and helped transform it into the company it is today. Over the years, the Silvis have owned and mined several large sand deposits under the name of Sahara Sand. In the late 1990s, they were able to secure a 1,000-acre sand deposit in Eagleswood, N.J., that contains more than 130 million tons of reserves. This, combined with their other sand operations, will allow Sahara Sand to be a major distributor for many generations.

Gibraltar Rock operates two facilities, one in Belle Meade, and the other in New Hanover, Pa., currently going through government approvals. Together, the two quarries have more than 400 million tons of reserves.

Gibraltar Rock
484 County Route 601
Belle Mead, NJ 08502

Key Personnel:
Rick Parton, Director of Mining
Aidan Kilcoyne, Plant Manager
Bryan Park, Assistant Quarry Manager