A major dolomitic limestone operation creates new productivity for an old quarry and reduces energy costs at the same time.

By Carol Wasson

Several years ago, the Carmeuse Lime and Stone Quarry in Cedarville, Mich., hit a do-or-die point — “either rebuild its entire crushing facility or flounder,” says Ray LeClair, the site manager hired as the go-to guy to get a new plant up and running. The challenge was replacing equipment from the 1930s, which had been moved to the site in the 1950s, where it had operated with no upgrades other than maintenance for the next 50-plus years. Beyond that, the old primary crusher was located nearly a mile and a half from the quarry face, requiring three 150-ton trucks to haul material from the face to the primary feeder, then haul the crushed material to a secondary crusher near the edge of the quarry.

Current and future crushing capacity goals led to the selection of a robust jaw crusher at the primary. Able to process up to 1,600 tons per hour, the crushing circuit is unlikely to become a plant bottleneck.

“We had experienced numerous breakdowns with the operation of equipment that was just worn out,” LeClair says. “Upgrading was the right thing to do. We would reduce hauling, energy, and maintenance costs, all while increasing our productivity and profitability.”

Project planning began in 2007 with the major initiative being the design of a new two-stage crushing system in the pit, closer to the face. Crushed material would then travel on a newly installed 4,000-foot conveyor to an existing surge pile and rail load-out system. Material loads onto a private 14-car rail system to be transported 5 miles to an existing finishing plant and ship-loading facility where product is transported via freighter to numerous Great Lakes ports. More than 60 percent of the operation’s products supply the steel industry.

LeClair says that the project started out on the fast track and was scheduled to be online in July of 2008, but progress slowed and eventually came to a halt when then-owner Oglebay Norton sold the facility to Carmeuse North America. After some evaluation by the new owners, the project continued, and the new crushing facility was completed and started up in the spring of 2009.

Throughout changes in direction, design, and ownership, and into installation, startup, production, and current troubleshooting and diagnostics, one thing remained consistent — an atmosphere of close collaboration between LeClair and Telsmith, Inc., the company chosen to design and engineer the new crushing system and plant. According to LeClair, the manufacturer ultimately simplified a complex process by managing the project as a “singular source backed by a combination of resources.”

In-house design and engineering

After researching a number of plants and operations, LeClair says his manufacturer selection was based on its in-house design and engineering team. “From the very beginning, I worked closely with one engineer who was designated as the point person — although he did have the support of his entire staff,” he says. “We narrowed the focus to just two people — he and I. All questions would be funneled through us. This streamlined the project and made everything go very smoothly.”

The breadth and depth of Astec’s capabilities and resources eliminated confusion between different entities who might have otherwise designed various parts of the plant, he says. With the entire design under one roof, they were able to fast track the project and handle even the smallest details within the design upfront.

A modular plant concept

A modular plant concept was chosen for its two-stage crushing system. Modularity may shorten the time line for new plant development and streamline the installation process. Pre-designed modules are pre-assembled at the factory and ship in segments.

Automation allows the plant to be monitored remotely or through the control house.

LeClair says that, although modularity enabled the plant to be fast-tracked, he favors the design concept under any type of construction schedule. “No matter what the pace, I prefer the modular construction, as it creates a far better structure altogether,” he explains. “I like having these welded fabricated structures completed in a shop environment versus out in the field. You get the best penetration on the weld.”