Lots of women are quite strong.

Most modern mining equipment doesn't require extraordinary strength.

There's zero indication that hiring women negatively affected or affects productivity.

Women tend to have greater endurance because they have more type I ('slow twitch' or oxidative) muscle fibers, which produce less force but are more resistant to fatigue.

Women have always been hunters, and warriors, and pirates, and done heavy work - on farms, on pioneer settlements, etc.

The fact that in general, men have greater upper body strength is not some kind of slam dunk for anything. Nobody was forced to hire unqualified workers. Give it a rest already... You're embarrassing yourself.