Upon trying to fill the growing need for aggregates to Florida’s construction industry, officials at White Rock Quarries made a decision — a big decision.
While the Miami-based quarry company already had a dragline with a 58-cu.-yd. bucket, it wasn’t meeting customers’ demand, so White Rock officials decided to nearly triple its fleet’s bucket size by purchasing a new production tool — a dragline with a 150-cu.-yd. bucket.
“This is an upgrade from our previous machine, which was a 58-yard dragline that had been commissioned in December 1995,” said White Rock Quarries President Jim Hurley. “Based on the growth of our quarry and our production capacity, we needed a bigger machine to meet the growing demands.”
The Marion 8200 dragline went into service excavating limestone in late September 2005 at the company’s Miami quarry. It will only be used in this location.
“This is not something you pick up and move,” Hurley said. “This is the largest of its type in the aggregate business in the U.S.”
With 275 employees and more than 250 major accounts, White Rock Quarries is one of South Florida’s leading limerock aggregate producers and one of the nation’s top-three producers of crushed stone.
Since starting operation in 1986, White Rock has become well-known for its production of high-quality limerock — also known as limestone — for customers throughout Florida’s East Coast.
When plans for White Rock Quarries, a division of Vecellio & Grogan which is part of the Vecellio Group, were initially formulated more than 20 years ago, the entire operation was designed for high-volume production. To this day, production at White Rock Quarries is a continuous cycle of drilling, blasting then excavating the limestone by dragline.
Upon being excavated by the draglines, limestone is loaded into 85-ton Cat off-highway rear-dump trucks and hauled to the crushing plant, where DOT-certified aggregates and a range of fine screenings are processed. From there, White Rock’s fleet of Cat 988 loaders load customers’ trucks, which are weighed out on four outbound scales featuring remote ticket printers. With its mining operation located near the Florida East Coast Railroad, White Rock can deliver aggregates and screenings by rail from Miami to Jacksonville.
The new 150-cu.-yd. capacity bucket and dragline — which can hold 100 tons of blasted rock — makes its way around the quarry by “walking” 7 ft. at a time on 12-ft. by 60-ft. “shoes.” Hoisted by a 275-ft. boom swiveling on a 58-ft. base, another bucketful is dumped every 75 seconds. At two shifts a day, that’s 24 million tons of limestone per year.
The Marion 8200 was relocated from New Mexico, as the 6.75-million-lb. machine was disassembled and shipped to Miami using 175 semis — some up to 13-axle, 50-wheel vehicles. Even after arriving in Florida, 35 technicians working 10-hour shifts, seven days a week for a year were needed to complete the reassembly.
The machine runs on electricity, requiring its own power substation and an inches-thick extension cord to operate the 14 onboard motors doing all of the hoisting, swinging, dragging and propelling. Together, the motors generate more than 14,500 hp.
“It has increased our capacity to mine the raw products that are produced into finished aggregates and screenings and base rock to meet Florida’s ever-demanding needs for highway construction, commercial, light industrial and residential construction; supplying all the various raw products that are incorporated into asphalt —ready-mix concrete, block, paver bricks, roof tiles — everything that’s used in regard to the overall construction of Florida’s needs,” Hurley said.
(This article originally appeared in the spring 2006 issue of the Florida Transportation Builders Association’s Florida Transportation Builder magazine.)