UPDATE 2-Potash Corp workers give strike notice for Friday

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By Roberta Rampton

WINNIPEG, Manitoba, July 23 (Reuters) - About 500 workers at three potash mines owned by fertilizer giant Potash Corp of Saskatchewan (POT.TO: Quote, Profile, Research, Stock Buzz) could be on strike or locked out as early as Friday because of a contract dispute, the company and the United Steelworkers union said on Wednesday.

Both sides said they were still willing to negotiate and hoped to avert job action that could affect production of potash, a fertilizer in hot demand because of tight global supplies and strong demand from grain farmers trying to boost yields amid a world food shortage.

But there was a "significant difference" between the company's position and what the union wants, said Roger Falconer, head of the strategic campaigns department at the union's Canadian head office.

"We have a serious problem, because this corporation is making immense, obscene amounts of profit, and we believe that they have the ability to pay, and we're asking for something better than their final offer," Falconer said in an interview.

The union will be in a legal strike position at the Cory, Allan and Patience Lake mines as of 1 p.m. local time (1900 GMT) on Friday, Falconer said. Potash Corp would also be able to lock out workers at that time.

"At this time, we do not have any formal negotiations scheduled with the union, but the lines of communication remain open," said Bill Johnson, a spokesman for Potash Corp.

"We remain confident that our offer is a very fair and competitive one, and we're hopeful that it will be the basis for a negotiated settlement," he said.