Inch by inch, new headframe takes shape

[ NOVEMBER 30, 2009 - KEVIN WEEDMARK ]

First it was eight inches an hour, but by late last week the pace had picked up to 11 inches an hour.

That’s how quickly the headframe at the PotashCorp Rocanville Scissors Creek site rose above the prairie.

And as you read this, one of the most visible stages of PotashCorp Rocanville’s $2.8 billion expansion should be newly completed.

The pour was started Friday, Nov. 20 at 1 p.m. and should have been completed this morning at 58.5 metres.

“Things have gone fairly well,” said PotashCorp’s Shawn Munroe, “Temperature obviously impacts the curing of the concrete, and the weather has been favorable. If it’s colder they have to provide heating to prevent concrete from freezing.”

While the head frame slowly rose last week, winches for the shaft sinking started being installed last week and work continued on the ground freezing system. Once the headframe slip pour is completed, work will focus on getting the headframe outfitted for shaft sinking. “There is still lots of workd ahead but this is a significant milestone for the project,” said Munroe. “Everyone is to be congratulated for their efforts and for working safely on the project.”

The concrete pour started a few days later than originally planned as crews worked to ensure everything would be in place for the massive project.

“We were waiting on materials, and trying to get things completed in time to start the procedure,” said Munroe. “Once you start, you’re committed to continuing—you don’t want a big seam in the headframe, so you need to ensure everything is in place.”

He said a lot of attention is paid to concrete quality control. “There’s quite a workforce just dedicated to the concrete quality,” said Munroe. “There are eight people just devoted to concrete quality.”

And there is a lot of concrete in the headframe. Murph Miniely, assistant project manager for AMC, says there are 6,000 cubic metres of concrete in the headframe structure, 2,600 in the slipform pour and the rest in the foundation.

The entire structure will weigh 15000 tonnes, including 180 tonnes of steel.

Crushrite Concrete was delivering four to five truckloads of concrete an hour to the site. The pour continued 24 hours a day, with 113 workers on the day shift and 67 on nights.

Miniely said the pour had gone without incident by Thursday afternoon. “We always have contingency plans,” he said. “We always plan for potential problems, and we have the personnel and resources in place to deal with them if they come up.”

Munroe said that after looking at the plans on paper for so long, it’s nice to see the headframe take shape. “It’s kind of neat to see the headframe going up,” he said. “You see it change on a daily basis. It is visible from the highway now so I see it when I go to work.”

Once the headframe is complete, the long process of sinking the shaft will begin.

That process will take two and a half years, and the entire project will wrap up in 2013.