The railveyor is a cross between a railroad and a conveyor system that is propelled by foam-filled tires at drive stations located at intervals along the track. The tires provide the forward thrust by turning against the cars’ side plates.
“We’re going to go in with a twin ramp concept,” said Golde. “One ramp will be dedicated to the railveyor. The other will be used to bring in people, supplies and equipment.”
The installation will be used to demonstrate the technology in an underground environment and test an integrated loading system. The material will be transported to surface, dumped and trucked to the company’s Clarabelle Mill, but could also be transported directly to the mill via the railveyor at some point in the future, said Golde.
“Pending the outcome of that, we’ll decide whether or not to put it into full production. We’re still at a research stage until we’re satisfied that all the pieces work well together.”
Rail-Veyor Technologies has a 37.5-inch gauge test track at Vale’s Frood-Stobie site in Sudbury. It’s outfitted with a loading, dumping and reinversion loop to demonstrate the technology’s capabilities, “but that kind of structure would only be possible in a fairly fixed type of installation,” said Golde.
“We will need to load the railveyor when we’re doing development work and extending our ramp systems and production areas, so we’re looking at something that is portable, mobile and compact – in other words, a continuous loading system at the front end of the process that will grab the broken muck with some sort of conveyor system and feed the train.”
Railveyor drive stations are spaced at intervals along the track, depending on the train length and track grades. Sensors at each drive station detect the approach of the railveyor and power up. When the last car moves through a station, the power turns off.
The gaps between the cars are sealed by flexible flaps that prevent spillage and form a chute for dumping the material.
While proceeding up a 20-degree grade, the cars can come to a complete stop and resume progress even when fully loaded.
The railveyor is ideal for both underground and surface applications, said Patrick Fantin, Rail-Veyor Technologies’ vice-president, technical. In addition to applications in the mining industry, it can be used to haul iron ore, coal, wheat, corn and aggregate.
In fact, Vale’s interest in the railveyor at a corporate level indicates that it is being evaluated not only for applications in Sudbury, but also for application in other jurisdictions and for other commodities. According to Golde, “there’s a very real possibility that it could be used for surface mining applications,” though it would probably be scaled up and the cars designed to a width of 48 inches instead of the current 30-inch width.
The only existing installation of a railveyor system is at Harmony Gold’s Phakisa Mine located near Odendaalsrus in South Africa. The underground system was installed in 2006 to transport ore a distance of 5.1 kilometres for hoisting to surface. In 2009, a second railveyor train was added to boost hauling capacity.
The electrically powered railveyor is able to replace diesel-fueled haul trucks, requires smaller openings and can negotiate corners with a minimum 30-metre radius at speeds of up 32 kilometres per hour.
According to Fantin, an electrical engineer with 23 years of service at Falconbridge and Xstrata Nickel, the railveyor concept was developed in the ’60s in France, but was abandoned because of technological limitations at the time.
“Back then, the only way to control speed was with DC motors and they’re very expensive. What brought the railveyor forward today is that in the late ’90s, an American inventor, Mike Dibble was able to resolve a lot of the mechanical issues.”
Low horsepower AC motors with variable frequency drives, fibre optic networks, programmable logic controllers and human/machine interface technologies have come together to make railveyor technology possible, said Fantin.
The system is billed as being easy to install, move and reconfigure.
“The cars weigh about 1,500 pounds each and we’re loading roughly a tonne into them, so there’s less than three tonnes of weight in each car, and we’re putting it on 40 pound rail,” said Fantin. “Because the loading is so light, you don’t need to install wooden ties or concrete ties. A threaded rod every metre or so on the track holds it in place. To dismantle or reconfigure it, you just undo four bolts, lift up a section of track and carry it away. The surface preparation is a standard roadbed.”
The railveyor’s low headroom makes it easy to cross roads or waterways. Unlike heavy rail systems, there’s no need for large civil structures. “A culvert will suffice, with a road over top of it,” said Fantin.
The marketing effort has been limited so far to demonstrations at the test track and a few sales trips to the U.S., said Joe Einerson, Rail-Veyor Technologies’ general manager of sales.
“They all love the concept and think it’s going to be great,” said Einerson, but new technologies always take some time to win acceptance.
One challenge railveyor users in the mining industry will have to overcome is the handling of oversize material.
Vale is currently testing several loading and crushing technologies at the test track, including a crusher from New Dimension Technologies that fits into an excavator or loader bucket.
Such a crusher system would facilitate the loading of muck directly from the face into the railveyor cars, eliminating conventional crushers and ore pass infrastructure underground. The alternative would be to use the railveyor to move material after it has been dumped and crushed.
Vale hopes to minimize the amount of oversize material by controlling the fragmentation, but “there are other solutions, including rockbreakers and portable crushers that could be used, said Golde.
The objective is to achieve a target level of five per cent of total material larger than 18 inches.
The 53-car railveyor at the test site has chalked up approximately 8,000 loops around the 750-metre track in Sudbury – many of them fully loaded, “so the railveyor concept has been proven,” said Fantin. “We know we can load, we know we can transport and we know we can dump. Now, it’s just a question of continuing to optimize our designs and add functionality to offer a broader suite to our clients.”
Further energy savings, for example, will be achieved by changes to the power system that will store and make use of energy generated by the railveyor when it’s going downhill.
Rail-Veyor Technologies’ test track at Vale’s Frood-Stobie Complex represents an investment of $10 to $12 million.