Nickel, which has been up towards US$20,000 per tonne, closed down almost 0.7% to $19,382.50/t.
In Canada, the United Steelworkers Local 6500 union has recommended a tentative wage agreement with Vale after two weeks of "challenging negotiations", which could see an end to a strike that's hobbled the Sudbury operations since June 1.
The union said 2,500 members were voting electronically on the tentative agreement until 11pm last night.
Mining equities had a generally positive day in Toronto after a public holiday, with Barrick Gold up 0.26%.
Anglo American led gains by mining majors in London, up 2.82%.
Vale closed flat in Brazil.
BHP was up more than 1.85% in midday Australian trade.
Finally, the gold price was similar to yesterday on the spot market, around $1,809 an ounce at the time of writing.