Sure copper also pays the bills, but ideally you want higher nickel and higher platinum group metals. Copper comes as CuFeS2 and all that sulfur should end up as sulfuric acid. This has to be sold or given away and shipped somewhere. The same is the case of nickel, it is just that nickel pays better. So if your production capacity is limited by SO2 regulations, you are better off producing nickel. From far up north selling and shipping acid is always an issue. Where are the buyers and how far do you have to ship, plus nobody likes having trains or tankers of acid passing their neigbourhoods

SO2 emissions, government regulations and transport of sulfuric acid are the big drivers for all sulfide based mining operations.

Long term, Sudbury should be the spot to ship nickel concentrate from the ROF since they got all the processing and infrastructure needed, and in spite of strikes etc they will not shut down permanently. Sudbury may actually become the central hub for all nickel processing in Canada; already now concentrates from Ragland, Voisey's Bay and various mines in Sudbury all end up there.

One thing about the economics of nickel is that NOT as well as anyone else will have to pay custom fee treatment charges wherever they ship the concentrate, so when doing the economics you will never get the full value of the nickel when selling it as concentrate. Typically the mining costs are in the 50 to 60% range of the total cost of overall processing. I suspect that either Vale or Xstrata(or joint "Sudbury Nickel") will eventually buy up NOT as well as anyone else with nickel in the ground.