February 4, 2010

GORF CONTRACTING LTD. PHOTOS

The 68,000-pound steel absorbing tower is hoisted onto a flat bed for delivery.

Mine tower largest steel project ever undertaken by Gorf Contracting

PETER KENTER

correspondent

It looked like an Apollo rocket ship heading down Highway 101 from the Gorf Contracting Ltd. manufacturing facility in East Porcupine, Ont. What it actually represented was delivery of the largest steel project the company had ever undertaken.

The item? A 15-metre-tall steel absorbing tower designed to process acid at Xstrata Copper’s Kidd Mine and Metallurgical Plant a few kilometres away.

“At 17 feet (five metres) in diameter and weighing 68,000 pounds, (31 tonnes) it’s the biggest tank we’ve ever shipped fully assembled,” says Jeremy McCoy, Quality Control Assurance Manager with Gorf. “We’ve done some tanks with a larger diameter, but this one was the tallest. We had to modify our shop doors so we could bring it in and out and even had to build a bit of an extension on the back of our shop.”

The structure was so long, that the ground level of the ramp at the rear shop doors was raised to allow the tank to be taken outdoors without its nose getting caught in the doorframe.

GORF CONTRACTING LTD. PHOTOS

When it arrived, the tower was installed on a concrete pad with steel supports made of channels and beams.

The tower was constructed of two types of steel, stainless on top and carbon steel on the bottom, with tank thickness ranging from 1/4-inch to 5/8-inch thick. Fabrication of some of the thicker plates was sub-contracted to Hodgson Custom Rolling Inc. of Niagara Falls.

The tank was constructed from rolled steel plates and assembled using an automated welding oscillator. Placed horizontally on power rollers, the structure could be automatically adjusted into any position required by the work crew.

Absorbing towers are lined internally with brick after installation and have a service life of about 25 years.

The rush job took from late May to August to complete.

“Every job is a rush job, and the quicker you get it out, the quicker you can start another,” says McCoy. “But we had a stern delivery date, because the tower was slated for installation during a production down-time at the mine.”

Although the delivery destination was just a few minutes away, the route involved eight turns, with the tower destined for the farthest end of the Xstrata property. The company contracted Anderson Haulage to provide a transport truck with a special trailer bed for delivery.

“The back of the trailer could be steered independently of the front and it helped them to manoeuvre around tight corners,” says McCoy. “We rolled the tower out of the shop on the power rollers, then used two cranes, one of our own and another from Kerr Crane Service in Timmins, to lift the tower onto the truck bed.”

The roadway along the transportation route was closed to traffic during the delivery.

“Even on its side, the tank was tall enough that we had to call in NorthernTel and Hydro One, so they could lift the utility wires out of the way for us as we passed underneath them,” says McCoy. “We only had a clearance of about five inches as we travelled under the Dome Mine overpass, but that was by design. We would have taken an alternate route if the tank had been even slightly bigger.”

The pair of cranes used at the Gorf site moved ahead of the delivery truck to install the tank at the Xstrata facility.

“We stood it up on a concrete pad that we fabricated, complete with a steel support made of channels and beams,” says McCoy. “The job went off without a hitch.”

Like an Apollo rocket in reverse, the Eagle had landed.

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