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--  TRUCKING   --

Extended Haul

By Tony Kryzanowski

trucking01.jpg (33999 bytes)
Using the Central Tire Inflation (CTI) control
panel that sits rights in the cab, logging
contractor Jack Thomson (below) shows
how drivers can increase or reduce tire
pressure. Thomson says he would recommend
CTI, which has considerably extended his
hauling season for Weyerhaeuser.
trucking02.jpg (52142 bytes)

The combination of steep grades and clay-based soil usually means a short log hauling season. But one Alberta logging contractor has extended his working window by installing new central tire inflation (CTI) equipment on his trucks.

The equipment costs about $28,000 per truck to install, but logging contractor Jack Thomson, owner of South Cariboo Enterprises Ltd., has been able to increase the number of operating hours per truck from 2,000 hours to around 4,000 hours annually.

Thomson is a stump-to-dump contractor working for Weyerhaeuser in Grande Prairie. To date, he has eight trucks with CTI equipment, and has operated them for three and a half seasons. Weyerhaeuser asked him to install the equipment because they were about to begin harvesting timber within an environmentally sensitive area. They guaranteed that his hours per truck would increase from 2,000 to 3,000; Thomson has now surpassed those numbers, and is up to as much as 4,000 hours.

"This year out of 12 months, we’ll get nine and a half months in," he says. "The steady work has really helped to keep our people around. Plus, CTI gives us more steady cash flow for the summer. When the logging season is normally shut down, our trucks are still going. It has really helped us in that respect."

CTI is a computer-controlled system that allows log truck drivers to deflate and inflate their tires, either parked or on the go. With reduced tire pressure, logging trucks have a larger tire footprint on the ground, resulting in better flotation, better traction and less environmental damage.

A typical installation gives the driver three options: a log road setting of as low as 30 lbs. psi, a corridor road setting of between 50 and 60 lbs. psi, and a main road setting of 90 to 100 lbs. psi. The computer control panel sits right in the cab. Weyerhaeuser has purposely limited the number of pressure selections drivers can make.

Two manufacturers provide South Cariboo Enterprises with CTI equipment. They are Eaton and Tire Pressure Control International. No special tires are required, and there is only slight additional wear and tear.

"Once you understand the system and how to work it, it is a fairly inexpensive system to operate and maintain," says Weyerhaeuser log haul coordinator, Nelson Anderson. "There is very little damage done to the tires if the driver is using the system properly. "He says Weyerhaeuser Grande Prairie became interested in the system after it was tested at their Prince Albert, Saskatchewan mill. The Grande Prairie mill needed wood flow through the summer and a log haul system that left minimal impact on the environment. CTI has provided a longer log haul season with very little environmental damage.

The availability of CTI trucks plays an important role in Anderson’s log haul planning. "The CTI trucks will be in the wetter ground and steeper blocks, "says Anderson, "and conventional logging trucks will be in the flatter, frozen ground. One of the reasons CTI was brought in was to go to work in environmentally sensitive areas."

Thomson says the low inflation factor does much more than simply reduce ruts. "We can basically seal or heal a road by straddling the ruts back and forth," he says. "On a conventional haul we’ve had trucks hauling right beside us with no CTI on the same road, and they fall right out of sight. The front axle just drops."

He adds that CTI is quite a simple system to learn. While tire wear and tear has been minimal, the largest problem they have encountered is with drivelines.

"With lower pressures and soft ground, we didn’t realize the torque we were getting with a bigger footprint from the tires," Thomson says. "Our biggest problem in the first year was taking drive lines out, literally winding them up like a pretzel."

To alleviate this problem, they began taking lighter loads on really soft ground, then topping up the loads further up the hill, and then heading into the mill with a full load. South Cariboo Enterprise’s rather unique truck picker system makes this possible. Many other logging contractors have log loaders stationed in cutblocks to load trucks. Thomson runs eight trucks with self-pickers. His drivers can load partially at the bottom of a hill, climb the hill at a lower tire pressure, then top up with wood piled at the crest of the hill.

Thomson pointed to a number of roads with steep grades where his CTI trucks have been able to load and deliver, but where a conventional logging truck would require a dozer to pull it up the hill. Another way to improve traction for conventional logging trucks is the expensive application of gravel. With CTI, Thomson has managed to save on both of these expenses.

He says he would definitely recommend the CTI system to other contractors because it extends the haul season, thus helping keep good drivers, provides better flotation, causes less environmental damage and requires less support by way of dozers for pulling and application of gravel.

Weyerhaeuser provides new CTI drivers with one-day training and Thomson has them travel along with an experienced driver for about a week. Anderson says drivers do not require a lot of additional training to use CTI, but must realize the road conditions they are in, and know how to adjust their tire pressure to match those conditions.

A new twist on CTI that Weyerhaeuser is currently monitoring is the combination of CTI and a tri-axle tractor. This should provide even greater traction in cutblocks. They are currently in discussion with the Alberta government to establish load and configuration guidelines regarding tri-axle tractors, so that everyone is satisfied that these trucks can be operated safely according to established load and manufacturers’ specifications.

The Forest Engineering Research Institute of Canada (FERIC) has an active research program as it relates to CTI. They have been gathering data from South Cariboo for the past three years, as well as from Al-Pac who is also using the CTI system on their log trucks.

Use of CTI is mandatory with all of Al-Pac’s log haul contractors, according to their fibre procurement specialist, Randy McNamara.

They have 85 trucks using CTI, and have been using the system since 1992. Among the main advantages they have noticed are a longer haul season in summer time because of less damage done to gravel roads and better traction on icy roads in winter. Traction on steep grades is really not an issue in their area.

They believe the experience has been positive. Unfortunately, they have not been able to measure exactly how little damage CTI trucks are causing to gravel roads because most of these roads are also used by the public.

In terms of systems operation, McNamara says they have required a fair amount of continuous maintenance to keep the airlines clear. Contractors have worked with manufacturers to make modifications, such as installation of double air dryers to keep the air hoses clean.

FERIC’s eastern division has developed a prototype system that installs CTI only on the tractor’s drive axles, which could greatly reduce the cost of installation. The components they used are available from most truck parts dealers and, because only eight tires are involved, FERIC adds, there is no need to change the tractor’s air compressor.

One unit is being tested in northwestern Ontario, and Highland Pulp in Nova Scotia is testing another. To date, drivers report no maintenance problems with these scaled-down versions.

While there has been considerable advancement in technology and research as it relates to CTI, Weyerhaeuser’s Anderson says the success or failure of the system really depends on the driver. South Cariboo Enterprises operates their CTI trucks successfully on steep grades, and have a number of longtime drivers dating back to when they first introduced CTI. That driver continuity, going so far as to knowing how to use the CTI truck to heal the road, has really contributed to their success.

Al-Pac’s McNamara agrees that adequate driver training is essential for successful use of CTI. They have even developed a video about CTI use that they ask contractors to share with their drivers.

While truckers may soon have the ability to purchase scaled-down CTI versions, there are other advantages to the full-blown version, as demonstrated by a recent experience.

A FERIC vice-president decided to witness CTI first hand by touring a cutblock managed by South Cariboo Enterprises. He was riding along with a log truck when, purely by coincidence, one of its tires punctured. He was certain they would be stuck in the boonies till help arrived. But the driver simply hit the ‘continuous inflate’ button on his CTI control panel, pumped air into the tire at the same rate as it was losing air, delivered his load to the millyard, then drove the truck to the tire shop.

The vice-president was duly impressed by CTI’s capabilities.


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This page last modified on Tuesday, February 17, 2004