Mining Engineering-Dec 2010

by William Gleason, Senior Editor

From a distance, the 0.75-km (0.5-mile) rail line that sits in the shadows of Vale-Inco’s Stobie Mine outside of Sudbury, Ontario could be mistaken for a standard conveyor belt hauling ore from the nearby mine. But with its large, yellow-painted loop and interconnected green rail cars that invert themselves on the loop before correcting with a smooth rollover further down the track, one might assume that this is some sort of test track for a new roller coaster. The fact of the matter is that it is the proving ground for Rail-Veyor technology, a technology that the company hopes will one day change the face of ore transportation in surface and underground mines around the world.

With a line of linked, low-profile rail cars that are capable of carrying up to 1 t (1.1 st) per car of ore by way of simple, above ground, lightweight rail track, the technology is not groundbreaking.

In fact, it was developed in the 1960s for the French State Railroad. A demonstration plant for the Florida Institute of Phosphate Research was installed in 2000 and the first commercial underground installation was in 2007 in South Africa at Harmony Gold’s Phakisa Mine. There, a 4.7-km- (2.9-mile-) long tram between two shafts operates three Rail-Veyor trains on a shared track. The difference is that the application that is being tested day-and-night in Sudbury is getting closer to wide production, thanks to the use of computer controlled automation that has helped turn an old idea into a cost-effective modern solution.

“We have a niche here,” explained Rail-Veyor President and Chief Executive Officer Mike Romaniuk. “We have a simple technology that can do a lot of things that traditional conveyors, trucks and trains cannot do. It has low maintenance costs, no on board driver or operator and requires little energy.”

The driving force to move the train consists of a series of equally spaced dual-stationary drive stations with motors and gear reducers that turn horizontal tires against the side drive plates of the cars, providing forward thrust.

These computer-automated drive motors are what separate this version of the technology from previous versions. With modern programming and sensors, speed is controlled with a variable frequency drive (VFD), which allows operation in either forward or reverse directions with sufficient power to start a loaded train from any position on the track.

The drive system has no integral drive unit on the train, so rail weight is only based on car and content weight, not engine weight typical of a conventional railroad operation. The trains being tested in Sudbury are capable of carrying 1 t (1.1 st), but Romaniuk said that larger cars can carry as much as 3 t (3.3 st) per car, and there is no limit on the number of cars that could be attached.

Drive stations are spaced based on train lengths and track grades. Additional energy savings are achieved by shutting down the drive stations when the drives are not in contact with the train. The drive stations are designed to provide sufficient power to operate the system on grades up to 20 percent and control the cars through curves with a minimum 30-m (100-ft) radius at relatively high speeds.

The design of the rail cars allows for operation in an inverted position by use of a double set of parallel rails. This feature allows controlled, nonstop dumping of the cars by turning through an outside loop.

The rail cars are connected with flexible flaps that prevent leakage, allow articulated movement and form a chute as the product is discharged to a crusher, grinder, mill, train, truck or ore pile.

This design allows the cars to be operated in the upright or inverted position. And, because of the design, the trains can be easily dumped and continuously loaded and unloaded using roller coaster technology.

The system has been undergoing testing in Sudbury since April and testing will continue as different weights, types of ore, turns and grades are tested. Romaniuk said that discussions are ongoing with many mining companies and that Rail-Veyor hopes to get tracks and cars out to mines soon.

“In terms of the future,” said Romaniuk, “we are limited only by our imagination. There are no theoretical limits for the system. The unit train lengths and number of trains on the system will directly influence capacity. The maximum operational speed has not been established, but based on torque, gear ratios and drive train diameters, speeds of up to 32 km/h (20 mph) are realistic.”

When Rail-Veyor begins landing in mines around the world, it will be a reflection of much of the innovative and crucial work that is being done on daily basis in northern Ontario, one of the most vibrant mining sectors in the world. From green field to reclamation Comprised of principal centers of Sudbury, North Bay, Timmins and Thunder Bay, northern Ontario’s mining supply service sector is a hotbed of activity, with about 500 companies employing approximately 23,000 people in every aspect of the industry.