Well put. I work in engineering at a large industrial plant very similar issues here. There is a huge effort from management aimed at improving workplace diversity but at least from my limited point of view seems difficult to attract female applicants for open positions. I think partially it's remote location our plant is not in a very attractive place to start a family etc. Also the issue you identified where "coal face" experience is seen as a rite of passage into upper management.

My sister is also a mechanical engineer she worked on remote mine sites for a while and then at a power plant. She took a few years off to have children and now has no desire to get back to that kind of lifestyle. She works for the government now.