System offers smoother ride and higher sustained tramming speeds
MacLean Engineering has introduced a front suspension system as an option for its MineMate suite of utility vehicles.
A boom truck with the front suspension system will be on display at the North American Mining Exhibition in Sudbury August 19 and 20. The company will also stage a “ride and drive event” allowing anyone interested to compare the ride in a front suspended boom truck with the ride in a conventional rigid frame version of the same truck.
Any of the MineMate utility trucks can be outfitted with the elastomer suspension system, but boom trucks, fuel-lube trucks and personnel carriers are the ones that typically do the most tramming and will benefit most from a smoother ride, said MacLean Engineering product manager Dan Stern.
“Those are the top three candidates, but we can install the suspension system on any of our heavy-duty articulated utility trucks because they all use the same carrier.”
The MineMate line also includes scissor lift trucks, anfo chargers and transmixers for hauling cement.
Higher speeds
The suspension system alleviates the bone-rattling ride operators of rigid frame trucks are accustomed to and allows for higher sustained ramp speeds, so there are benefits relating to both health and safety as well as productivity, said Stern.
“Underground mining environments are typically pretty rough and rugged and what the suspension does is it takes out a lot of the mid-range vibrations. If you hit a big bump or a pothole, the machine is going to bounce like it would in a pickup truck, but it takes out a lot of the mid-grade bumps that cause musculoskeletal and head and neck injuries.”
The development of the suspension system started three years ago for the company’s line of low-profile utility vehicles used in Saskatchewan’s potash mines, said Stern.
“Potash mines are typically massive,” he noted. “I was out in a mine in Saskatchewan three weeks ago and I think we drove 40 kilometres from the shaft to the face. The Mosaic Esterhazy K-1 and K-2 mines are joined underground and have roughly the same footprint as the city of Winnipeg, so operators are driving close to an hour to get to the workplace.
“We developed a suspension system for the low-profile mining trucks and it was received very well. From there, we said ‘Why don’t we put it on our other trucks for hard rock mining environments where there typically hasn’t been any suspension?’”
Trial
MacLean Engineering subjected a suspended boom truck to 4,000 hours of operation over an eight-month trial at HudBay’s Lalor Mine in Manitoba, and used accelerometers to measure whole body vibrations in the frequencies that contribute to spinal column injuries. Comparing the results with data from a rigid frame vehicle demonstrated a 35 per cent reduction in whole body vibrations.
A speed test from surface to an underground warehouse six kilometres away had the non-suspended truck complete the trip in 55 minutes versus 37 minutes for the truck equipped with the suspension system.
Leaf springs typically used in passenger cars, air springs used in highway trucks and hydraulic suspensions used in some off-road heavy equipment were found wanting in the underground environment, said Stern. Instead, MacLean Engineering scaled down and adapted an elastomer suspension system used on haul trucks in open pit mines.
The system consists of a series of stacked plastic discs similar to hockey pucks that absorb vibrations by squishing together.
There are no mechanical components, very little maintenance, no need for greasing and no replacement of wear parts.
The system also includes heavy-duty automotive dampeners, a purpose-built A-frame supporting weldment, and a Watts linkage stabilizer to reduce bump steer.
Customers can order MineMate utility trucks with or without the suspension system.
“We still have our customers who are value-oriented and want our standard machines, but we also have customers who are looking for solutions for their operators and who realize that the extra cost of a suspension system is far less than the cost of workplace injury claims,” said Stern. “The interest is definitely there. We have some mines, for example, that have decided any future purchases will be suspended
trucks.”
“Suspension is something that all equipment manufacturers are paying attention to. I’ve heard that some of our competitors are working on suspension systems for their heavy-duty articulated trucks, but we’re the first to market.”
