Longwall Mining







Ready to Roll! Rulmeca Motorized Pulleys Positioned for Increased Mining Demand

Published: May 17, 2011 |

“Motorized Pulleys have the potential to revolutionize coal mining production – making it faster, safer and more efficient.” Michael Gawinski, Rulmeca Corp. President

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The United States underground mining industry is showing signs it is ready to upgrade aging conveyor systems with Motorized Pulleys, and Rulmeca Corp. is poised to deliver.

The Motorized (internally powered) Pulley technology was developed specifically for mining applications in 1953 Europe. (See photo 1) Many decades and enhancements later, most North American Motorized Pulley installations are in above-ground bulk-handling plants, not in mines. But that could change, as awareness increases of the benefits over standard exposed drive systems.

Last year, North American coal producer Cline Resources became the first to upgrade panel belt drives with Rulmeca Motorized Pulleys in its West Virginia and Illinois coal mines. (See photo 2) After a successful one-year trial, Cline Resources added more to its inventory of conveyor drives, according to Rulmeca President Michael Gawinski.

As of March, U.K. Coal Ltd. had replaced the exposed drive systems in its coal prep plants with 85 Rulmeca Motorized Pulleys. “Our engineering policy is to continue to change out old exposed drives as our budget permits. The development of Motorized Pulleys to be used in underground applications of potentially explosive atmospheres could eventually replace many large and major conveyor drive systems that we operate,” says Steve Pringle, group coal processing engineer for U.K. Coal.

“In late 2010, Rulmeca Corp. faced 2011 with optimism,” says Gawinski. “After our first quarter’s performance, I adjusted the forecast, significantly upwards.”

In anticipation of greater demand by U.S. coal mines, the Wilmington, N.C.,-based Rulmeca also has increased its supply of production materials.

Ideal Coal Mine Solution
Motorized Pulley technology has become essential in above-ground applications, particularly ship-loading terminals. (See photo 3) Even stone quarries, foundries and recycling facilities have taken advantage of the product’s compact size and reliability.

While the design of internally-powered compact conveyor drives makes them ideal for underground mining, adoption in the U.S. market has required a considerable marketing effort. Gawinski traces industry skepticism about reliability back to the Motorized Pulleys of the 1960s and 1970s. “Concern is fading, with awareness of the performance of today’s models in underground mines, preparation plants and transfer terminals.”

Kerco Inc. President Chuck Reed saw a turning point in interest about three years ago. “We’ve been actively promoting Rulmeca’s Motorized Pulleys since the early 1990s. But it wasn’t until our company packaged (them) in our EZMP dual-drive conveyors in 2008 that we began to see significant interest from coal producers,” says Reed. (See photo 4)

In general, underground coal mines use numerous dual-drive systems as booster drives to spread effective belt tension along the length of the conveyor. A belt’s weight is significantly reduced by minimizing the amount of tension it must withstand. Light belt weight is essential for efficiently assembling and relocating conveyors underground. (See photo 5)

The problem with exposed drives is that electromechanical components, such as motors, gearboxes, sheaves, chains, sprockets and couplings, are exposed to harsh operating conditions. Motorized Pulleys are an optimal solution, housing the components in a hermetically-sealed, oil-filled shell. Lubrication is continuous, and heavy space-consuming cast-iron and steel enclosures are eliminated.

“Motorized Pulleys have the potential to revolutionize coal mining production – making it faster, safer and more efficient,” says Gawinski.

Today, Rulmeca’s Motorized Pulleys are available in diameters from 5.5 inches to 40 inches. They can achieve up to 330 horsepower and belt speeds of up to 1,320 feet per minute.

Testing and actual application of the new generation of Motorized Pulleys have demonstrated that Motorized Pulleys are more reliable. They also are safer. “Research and development to make Rulmeca Motorized Pulleys as user-friendly as possible is ongoing,” says Gawinski.

Expanding Mining Applications
As awareness about Motorized Pulleys grows among mine supervisors and engineers, so does the range of mining applications.

The newest, largest and most powerful Rulmeca Motorized Pulley, the Model 1000HD, is an example. “It was developed in response to requests from mines in North America, Europe, Africa and Asia, and unveiled in 2010, after years of design and full-load testing”, says Gawinski. (See photo 6)

Rulmeca and Kerco Inc. of Madisonville, Ken., joined forces in 2009 to develop the compact, lightweight EZMP dual-drive system, using two Model 630H 75-horsepower Motorized Pulleys in a nested configuration. Each pulley measures 24.80 inches in diameter and 55.12-inch face width and weighs only 2,200 pounds, much less than an equivalent exposed-drive system.

“This is a huge advantage when shifting conveyors underground, where space is restricted and panel belts are extended from 800-1,200 feet as continuous miners advance into the coal seam,” Gawinski explains.

In 2010, Rulmeca teamed up with Access Construction of Stone Mountain, Ga., manufacturer of the rugged MiniveyorUSA, designed with 5.5-inch-diameter minipulleys to power various conveyors in mines. These compact, portable conveyors can be placed adjacent to large, fast-moving conveyor belts to remove “carryback” (material that adheres to the bottoms of primary conveyors).

“It is dangerous to allow carryback to accumulate so that it rubs against the bottom of the belt and the return idlers,” says Gawinski. “Typically it is removed by manual shoveling from beneath a fast-moving conveyor belt and back onto it. But that is dangerous, too.”

Putting Rulmeca to the Test
Satisfied customers say Rulmeca Motorized Pulleys have proved their worth.

“The Rulmeca technology has now been thoroughly proven within U.K. Coal Ltd., and our confidence with the use of the equipment, and the service that we receive from the company continues to pay dividends to our business,” says U.K. Coal’s Steve Pringle. “The benefits from the safety aspect of improved access around drive heads and the vastly reduced requirements of guarding are invaluable in what is still a tough and challenging industry.”

A 100-horsepower Rulmeca Motorized Pulley was put to the test in U.K. Coal’s Kellingley mine in 2003. It replaced a problematic bottom-side belt conveyor drive at the tail end of the mine’s tailings conveyor. During a one-year trial period, it eliminated 30 days and 300,000 tons in lost production annually, according to Gawinski. Over the next three years, the drive system demonstrated an annual savings of tens of thousands of dollars in reduced maintenance expense and electrical power consumption, he says.

A yearlong trial at Cline Resource’s Maryan Mine in Illinois in 2010 tested the EZMP system by moving 1,200 tons per hour of ROM (run of mine) coal at 600 feet per minute on an extendable 48-inch-wide conveyor belt. Satisfied with the system’s reliability, Cline Resources (Macoupin Energy), installed the system at other mines.

“I’m happy we incorporated these drives into our mine, because their reliability and low-maintenance requirements will help us maintain our aggressive production rate,” says Todd Leverton, Maryan Mine superintendent. “We produce 9 tons of 11,000 BTU coal per man-hour with two continuous miners. We’re very proud of that.”

Motorized Pulley Development
Rulmeca Inc. began operating in the U.S. in 2003, as a member of the Rulmeca Group, which is based in Italy. The American affiliate’s focus is on sales, assembly and aftermarket service for the U.S. and Mexico in its mission to become the largest supplier of internally powered and hermetically sealed bulk-handling conveyor-belt drives on the continent.

The parent company manufactures and supplies rollers, Motorized Pulleys and components for global bulk-materials-handling customers through locations in 16 countries. “Our primary strengths are our strong focus on bulk-materials handling and our international scope of operations,” says Gawinski.

Rulmeca traces its roots to technology developed within two companies in Denmark and Germany in 1953. In 1995, the two plants merged at the Aschersleben, Germany.

As a separate event, Rulli Rulmeca S.P.A. was founded in 1962 and pioneered the Rulmeca idler roller, with precision ball bearings and a special sealing system, in 1964. In 2003, Rulli Rulmeca acquired the German company, along with idler manufacturing plants in England, Spain and Thailand.

This followed the 2000 acquisition of Precismeca idler manufacturing plants in Germany, Canada and France, and preceded the 2006 acquisition of Melco Conveyor Equipment in South Africa. Two plants in Germany were merged a couple of years ago as Rulmeca Germany GmbH.

Gawinski notes that many of the 100-plus employees at the German location have worked there for more than 30 years.

On the Road
Rulmeca hit the road with its exhibit of working motorized drives in 2008, and the cross-country miles it has logged since is likely another sign of building sales potential. Traveling to mines, power plants, steel mills, engineering companies, equipment manufacturing plants and transportation terminals, its actual North American circuit has averaged 33,000 miles per year, far exceeding the estimated average of 8,000 miles per year.

The exhibit shows how:
• A Motorized Pulley works

• A dual-drive system can extend belt and pillow block life

• Motorized Pulleys can be retrofitted into any conveyor, regardless of horsepower, brand and poles of existing
  drive motor to boost applied power to belt

The mobile showroom is comprised of a 7-foot-by-14-foot air-conditioned trailer behind a ¾-ton pickup truck with built-in diesel generator. The 100-square-foot walk-in exhibit contains several Motorized Pulleys driven by variable-frequency drives (VFD), a working Model 220M with a clear plastic shell; and a MiniveyorUSA conveyor.

“The conveyor demo enables Rulmeca engineers to explain how multiple VFDs in power-control mode offer superior long-term performance when compared with older ‘torque-control’ VFD algorithms,” says Gawinski. “Improved VFD control eliminates unscheduled conveyor stoppage in the event of slave-drive slippage. Torque-control prevents belt slip on the slave and overloading of the master.”

The exhibit also has a Model 320H cutaway, and visitors can watch short application-oriented videos from a high-definition television.

“The Rulmeca Road Show gives decision makers in the coal mining industry the chance to evaluate the performance of Motorized Pulleys by seeing it with their own eyes,” says Gawinski.

“They need to see, touch and feel products they intend to use underground. In general, conditions in underground coal mines are restricted and harsh for electromechanical equipment, not to mention people.”

For more information:
Contact: Mike Gawinski
Phone: 910-794-9494
E-mail: .(JavaScript must be enabled to view this email address)

To stop by Rulmeca’s website, CLICK HERE

- By Heidi Ketler, contributing writer for MiningConnection.com

Heidi Ketler, APR, is an accredited public relations practitioner and writer living in Roanoke, Va.