Proof that there used to be laws on the books banning women from working in mines, and feminists went and fought them. It's quite possible that the other reason you don't hear about female coal miners asking for more representation is that tech is worse at hiring women than coal mines are by now.
In China just recently in 2014, women led a massive Sanitation Worker strike. http://www.labornotes.org/2014/10/women-lead-sanitation-stri...
And also in the news in 2014 a female is head of NYC's Sanitation department. http://www.newsday.com/news/new-york/kathryn-garcia-named-ne...
What about the lack of women in relatively high paying skilled trades like electrician or elevator repair?
I think you'd get more bang for your buck by funding programs to help working class women move into skilled trades, than by trying to move middle class women who are already going to college from one major to another.