MONTREAL - Quebec Premier Jean Charest says the book isn't closed on Shell's decision to shutter a Montreal refinery -- its largest in Canada.

"We worked very hard to find people who were interested in the future of this refinery and we're not ready to let go," he told reporters Saturday following a candidate announcement for a provincial byelection.

The Calgary-based petroleum giant announced Friday it was closing its refinery in the city's east end after rejecting two final purchase offers.

The company announced it would convert the 76-year-old refinery into a distribution terminal instead.

The decision to close the refinery came as a blow to the 500 employees, including about 330 unionized workers and up to 400 contractors that had been hired for various projects.

An estimated 2,500 indirect jobs rely on the refinery's operations, which provide an estimated $240 million economic return for the city.

The premier said Clement Gignac, the provincial minister of economic development, has been given the mandate to find someone willing to continue to operate the refinery.

"We're going to continue to ask Shell refinery and their authorities about the decisions they're making in regards to the two offers," Charest said.

But the premier cautioned a deal isn't likely.

"It's not looking very good and we don't want to create false expectations but we're going to continue to work," he said.

The last oil shipment will arrive in August ahead of the final refining in September. Most of the 500 employees will be required over at least five months through the end of the dismantling and conversion process.

Shell is one of Canada's largest natural gas and petrochemicals producers.