All copper and nickel ores in Canada are sulfides and the sulfur has to be contained. In the old days it was oxidized to SO2 and emitted to the atmosphere. These days this is no longer acceptable and Canada(who is a lagger in this) is implementing stronger emission regulations. Normally the SO2 formed is converted to H2SO4(sulfuric acid) that has to be sold(or given away).

Hudson Bay mining in Flin Flon and Vale-Inco in Thompson presently are allowed to emit this SO2 to the air, but that will change by 2014. The problems include yes finding a taker(buyer) of the acid among other things. Shipping is another big issue since not too many towns like having tanker trucks full of acid driving by. I own VMS that is finding rich copper deposits close to Hudson Bay's operation but I am worried that Hudson Bay may shut down(huge capital costs) if the government actually enforces these regulations.

Xstrata and Vale in Sudbury also have lots of capital expenditures to improve their captures of SO2

There are buyers of acid in the world but safe shipping is very costly. When you visit Vancouver next time, just look across the bay(north shore) and you'll see a big pile of yellow stuff(sulfur from the oil indsutry) which will be sold and also used to make sulfuric acid.

ROF stands for Ring of Fire(nickel and chromites in James Bay lowlands)