If they bought a torch for $3,000,000 and produce 8400 metric tonnes (which is what the article quoted is how much they were hoping to produce) that is $357 per tonne for the year, of course that does not include electricity costs. I would hope the torch would last at least 5 years so the cost wouldn't be as high as you had figured.

There would likely be other costs associated with running the operation such as the construction of such a facitility which would be written off over a number of years just as would be for a torch.

The mill needs to find a way to dispose of chips since the pulp mill shutdown.