Pierre,
There is a lot of information available for operating equipment in Arctic conditions. Just Google Arctic Mining.
I was exposed to this fascinating topic when I visit a diamond mine to the North of Yellowknife in Canada. For instance, hydraulic excavators cannot just stand and idle as the hydraulic fluid would freeze in the various pipes leading to the cylinders, somebody has to jiggle the machine around every half-an-hour or so to keep the hot fluids circulating and the feeder pipes from freezing.
The main equipment suppliers like Caterpillar and Komatsu have dedicated Arctic mining equipment maintenance engineers and operational practices information bulletins, if you are interested in more background info.