I find that so interesting Sequoia - I too worked in mining and found it really easy to be a woman onsite. Never encountered any discrimination or had a hard time. I found the blokes really easy to work with and the women friendly - we tended to band together and support each other rather than the *****iness you hear about in other workplaces. I'm sorry that you didn't have a good experience.
Highly unionised production workforce and strike action was threatened often. The company was at the mercy of the union basically. The women were fabulous, I am still very close to a couple of them. I was told if I were a male I'd be on 10k more, by my own boss no less Mind you, I was 23 and it was my second job out of uni and all I saw were the dollar signs, ..... live and learn eh?