Super-size it

Taking a look at the big, bigger and biggest screening operations at an enormous Great Lakes quarry.

The 12-story structural steel and brick-faced screen building houses a total of 64 screens.

The mega 12-story-tall screen house at the Rogers City Quarry remains a landmark engineering feat amidst what is said to be one of the world’s largest open-pit limestone quarries. The structural steel-and-brick-faced building shields a massive circuit from the region’s often-blustery freezing climate. Monolithic in scope, a total of 64 screens process the material feed, sizing and separating from floor to floor. A variety of products are sent to stockpiles along the descent, with the finest material landing on the first floor as sand.

“The U.S. Steel group assembled this screening building in the 1930s to supply aggregate to its mills over the next several decades. They had a great deal of foresight as to its layout and overall efficiency,” says Ray LeClair, area manager for the Great Lakes division of Carmeuse Lime & Stone, which bought the quarry in 2008. Located in Rogers City, Mich., the quarry mines about 3,000 acres of its 8,000-acre site, with its products being shipped from the adjacent Port of Calcite, one of the largest ports on the Great Lakes.

Because the quarry ships between 6 million and 9 million tons annually, it continues to change out old equipment with new equipment, readying itself to meet upcoming demand. Over the last five years, the operation has converted screens from a number of manufacturers to those manufactured by Deister Machine Co.

“So far, we’ve put in more than 35 Deister screens throughout the building,” says LeClair. “Each is custom-designed for a number of varying tight footprints. In some cases, the ceiling height is less than 10 ft. – and four of the floors are fitted with 12 screens each.”

LeClair says that the Deister engineering team carefully designs the units to exacting specifications while setting each screening system at the right throw and vibration for our applications.

“Deister builds, assembles and tests the units at their plant so that they know that everything is set up correctly,” he adds. “Then they are shipped to us, disassembled, and reassembled once inside our building with the assistance of Deister service technicians, who remain onsite until all the units are running at peak efficiency.”

The Rogers City Quarry ships its products from the adjacent Port of Calcite, one of the largest ports on the Great Lakes.

A team effort
Additionally, an engineering collaboration among all parties, including the media supplier, has led to streamlined maintenance processes and an elimination of any contamination issues, LeClair says.

“Where we have had issues with contamination in the past, we have converted from wire cloth to polyurethane decks — as an occasional loosening of the wire cloth can sometimes cause the screen deck to pop up a little bit, allowing the potential for cross-contamination of the products,” he says, adding that all the engineering teams worked together to select the proper size and panel type for each application.

Where they once had to change out a 5 x 4-ft. wire panel, the maintenance crews are now easily handling 1 x 2-ft. urethane panels. He further explains that the deck is comprised of a multi-color cast urethane of yellow over red. Over time, as wear occurs, the red will appear and the crew knows it is time to change out that panel.

“Deister also works closely with the media supplier to ensure that all the rails are assembled in a manner that will maximize the wear life of the cross members on the screen units,” says LeClair.

With the need for so many screens, LeClair also stresses the importance of expedited delivery. During one of the more challenging phases of the screening operation upgrade, the quarry purchased a total of 23 screens.

“We weren’t able to place that order until very late in the year, and we had to have them delivered by mid-February so that we could be up and running by the first of April,” he says. “Deister bent over backward to make that happen, with the screens being delivered in a timely fashion and the installation completed that winter.” Because Deister screens are operating in all three of the company’s Michigan quarries, efficient parts inventory management is another key facet to profitability.

The deck is comprised of a multi-color cast urethane of yellow over red. Over time, as wear occurs, the red will appear and the crew knows it is time to change out that panel.

“Deister uses standardized American-made parts in all their units. By having Deister work with all three quarries, we are able to size components to make them interchangeable among the three locations,” LeClair explains. “This is where the strength of the engineering comes in to allow us the commonality between the sizes of the bearings and shafts that we require for the units. As a result, we can minimize our inventory of spare parts, and control our costs. And when we do need to add to our stock, Deister maintains a sizeable warehouse of readily available parts.”

Beyond the customer and equipment manufacturer relationship, LeClair acknowledges another synergy and similarity between Deister and the Rogers City Quarry: Both had recently celebrated their 100th anniversaries in 2012, and had been honored in their communities as well as the industry. In fact, the Rogers City Quarry is the subject of a documentary titled “A Century in Stone,” which tells the story of Rogers City and its calcite plant through the voices of its many dedicated and skilled workers, both past and present. Since its release, the documentary has been posted on YouTube.

Today, the Rogers City Quarry processes a variety of products, from 5.5 x 3-in. stone to a manufactured sand. The limestone is high quality and almost pure white. It’s used in the production of concrete, steel, sugar, glass, paint, chemicals and much more — and it’s predicted that that the site’s reserves will last up to another 100 years.

“Our material is shipped out over all five of the Great Lakes on both small and large vessels, from those taking only 15,000 tons to 1,000-ft. freighters handling up to 55,000 tons,” says LeClair. “To meet the needs of the region’s industries, we are committed to quality and ongoing processing improvements. Screening is such an integral part of our facility, we will continue to work with Deister on further innovations and on the customization that allows the greatest efficiency within our applications.”

Each Deister screen is custom-designed for a number of varying tight footprints, with ceiling heights of 10 ft. or less.

The 12-story Rogers City Quarry screening circuit is indeed super-sized, but perhaps even that statement doesn’t do it justice: “I don’t know of anything comparable to it in all of North America,” says LeClair.

Take note
The deck is comprised of a multi-color cast urethane of yellow over red. Over time, as wear occurs, the red will appear and the crew knows it is time to change out that panel.

Carol Wasson is a veteran freelance writer for the aggregates and construction equipment industries.

Photos: Rogers City Quarry

Material is shipped out over all five of the Great Lakes, on vessels carrying 15,000 to 55,000 tons.