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Freight Focus: Dry Bulk Hauling

by Jim Park

Depending where you call home in this vast country, the demand for bulk transport varies with the raw materials produced locally and the demand for certain raw materials to be used in different types of manufacturing.

Across the prairies, bulk tankers are a relatively common sight, laden with potash, fertilizer products and in some cases cattle feed. Alberta is a large producer of both cement and petrochemical products such as plastics and resins. While a large amount of that production winds up on a railroad car initially, much of it is later transferred off the railcar and onto a truck for delivery to a local customer. In fact, dry bulk hauling is an excellent example of how trucks and trains can work together to produce very efficient results.

Ontario, Quebec and Atlantic Canada are all large cement producers, and therefore have a sizeable dry bulk transport sector. Ontario and Quebec also enjoy a large automotive manufacturing sector which demands large quantities of plastics and resins for the autoparts manufacturing industry.

Then of course there's the edible sector. Flour, sugar, corn starch and other raw baking materials are often shipped to really large food producers in railcars, while the smaller producers rely on trucks to deliver the product. And with the amount of track that's being torn up by the railroads, the demand for dry bulk transport by truck should continue to strengthen.

Trucks and Trains

Anyway you look at it, shipping bulk commodities over long distances is what trains are good at. Delivering material right to the customer's door is what trucks are good at. It's a marriage made in heaven. That's why there are intermodal bulk transfer facilities in every major city on the continent.

According to Glen Friars of R.E. & J.E. Friars Limited in Saint John, N.B. the bulk transport industry is quite strong in Atlantic Canada. "We haul a lot of lime and cement for two major producers in the area, but we're now doing a lot of work for a major chemical producer as well," he says. "And most of the chemical work is coming off a railcar at a transfer facility. We certainly expect this business to strengthen in the coming years."

They're busier than ever and they've given rise to an innovation in the basic design of the dry bulk trailer.

Material can be transferred from the railcar to the truck by either a portable conveyor mechanism, which receives product from the bottom of the railcar and tips it into the loading port on the top of the tanker, or by portable pneumatic transfer pumps. These use a system similar to the method the tankers use to unload. The other method, the vacuum loader, literally sucks the product out of a railcar, then blows it into the tanker trailer.

The transfer process is fairly simple. The product can be loaded into the tanker from the top of the tank, through an opening called a manhole that has an airtight seal when it's closed and locked shut. To unload the product, the material is allowed to flow out of the bottom of a cone-shaped hopper into a fast-moving stream of compressed air. As the material drops into the airstream, it's blown along the discharge pipe and into the customer's storage silo.

A tractor-mounted compressor, called a blower, provides the airstream. The blower is designed to move large volumes of air, up to 4000 cfm (cubic ft per minute), at a high rate of speed and a relatively low pressure, usually no more than 15 to 20 psi.

The driver maintains an air-pressure balancing act between the inside of the tanker and the discharge line. Splitting the air flow from the blower and diverting some to the tank and the remainder to the discharge line creates the pressure inside the tank. The pressure inside the tank must be slightly higher than the discharge line, otherwise the material wouldn't flow out of the tank, but the other way around. This is accomplished by monitoring two air-pressure gauges and controlling the flow of air either into the tank or to the discharge line. It may sound complicated but it really isn't once you've seen it done.

The self-loading, or vacuum process, uses the intake on the blower to create a vacuum by drawing air from inside the tank rather than from a usual intake mounted on the blower. The tank itself is fitted with two large loading tubes, usually mounted on the rear of the trailer and appearing to stick out of the rear bulkhead. One pipe runs to the front of the trailer, while the other one protrudes only a short way into the rear area of the tank. Using the vacuum created by the blower, product is drawn from the storage silo into the tanker through the loading tubes. The different tubes are used to load the different sections of the trailer for equal weight distribution. There is a filter canister on the rear of the trailer designed to collect the dust produced by loading, and prevent it from being drawn into the blower.

Products and Process

The materials commonly transferred in dry bulk tanks range from material so fine that it behaves much the same way a liquid does, to coarse chunks measuring up to an inch long and a quarter of an inch thick. Some material is like dust, such as flour or cement, while other material, like plastic and acrylic, resembles tiny balls or cubes, and still other material is like flakes.

The driver is trained to unload the different products in the appropriate manner, with the unfortunate result in doing it incorrectly being a plugged discharge line. The clog can be cleared by actually blowing the material back into the tank but describing that process is best left to the driver trainers. If that doesn't work, it's time to get the shovel out and break the hose connection, letting the material flow out onto the ground. But that's the last resort.

Some materials require a high volume of air at a low pressure, others, the opposite. Some material, like plastics, can begin to melt in the discharge hose due to the high air temperature from the blower. It's all a matter of learning the different handling characteristics of each product. According to Bobby Doyle, the operations manager at Laidlaw Carriers tank division in Woodstock, Ont., the tankers are just like women. "They may look identical, but no two of them work the same." We didn't say that.

Since much of the material is either transferred off a railcar or produced fairly locally, much of the dry bulk trucking work is of a local or regional nature. Day cabs are pretty common in this business, meaning that a lot of the work sees the driver home every night. A large concentration of dry bulk trucking in southern Ontario is local or regional. Across the prairies, throughout Alberta and in the Maritimes, there is more regional work to be had. This still means fairly short hauls, usually empty one way, and the driver is often away only a few days a week.

That in itself should make the business a fairly popular alternative for drivers, but the pay is frequently a bit better than the more traditional modes of transport.

With a few exceptions, materials transported in dry bulk tanks are used primarily in manufacturing and are seldom delivered to the end user. In fact, that's one of the aspects that Clint Bonney enjoys the most about the job.

"The receivers never get all wound up about appointment times. When you're late, they're still glad to see you," he says. "And when you're really late, they're really glad to see you because they're probably nearly out of product."

Bonney hauls a dry bulk tanker for Laidlaw Carriers. When highwaySTAR caught up to Clint, he was unloading a load of silica sand at a precast concrete manufacturing facility near Woodstock.

He knows where he'll be tomorrow, and the day after that as well. But come winter, the business tends to slow down a bit. Cement used in construction isn't needed much in Canada because you can't pour concrete in sub-zero temperatures. But other products are fairly steady: plastics for manufacturing, flour for baking, and recycled glass and plastic from the blue box programs don't stop just because it's cold.

The slight risk to dry bulk hauling is the seasonal nature of parts of the business. The upside is you're empty half the time, and if you're good at it, you hardly ever have to get your hands dirty.

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