Those are interesting numbers. In my experience, the underground employees typically always make more than the surface employees, but this shows otherwise.
In relation to Noront, and the work they need done in the ROF, I am not sure these numbers would be applicable, since nearly all of the work would be done by contractors, who typically earn higher wages.
Contract underground miners make between $20-24 per hour, which they can earn overtime on. In addition to that, they make a production bonus, which would pay anywhere from $20-40 (sometimes up to $60) per hour. With the slow down in mining, bonus wages are likely to go down a little bit, with less demand for work. That is why it would be great if Noront could get some things done this coming winter on the winter roads, while the supply of skilled miners would still outnumber the demand for the work.