Mining is highly robotized. Here's a How It's Made video about mining uranium in Canada:

https://www.youtube.com/watch?v=9x7DozCqLxU

Other types of mines are less robotized, since they only have to worry about inhalation hazards, and not radioactivity. However, in most other types of mines, machines still do most of the drilling, lifting, detonation of explosives, and so on.

The biggest hazard in a modern mine is probably the accumulation of dust in enclosed spaces. I'd guess injuries during machine maintenance and repair come second, and cave-ins are a distant third. (I'm speculating though; I don't have data to back that up.)

I don't have an answer for mining specifically, but having worked in robotics in the past, I'd probably guess it's just fundamentally cheaper to pay very poor people to do it vs developing and maintaining new technologies. Unfortunately, because I could see the benefit to robotic mining technologies, heck maybe if we ever figure out how to feasibly mine asteroids or something they will get some funding.

The heavy machinery work until it does not. Someone needs to come down there and unjam it, replace the broken parts, so the maintainance and so on. It’s highly mechanized, but there are people who still need to keep it going.