Father’s Day in Australia was on September 2, and it’s a day a group of miners from “down under” won’t soon forget.

The problem is that extracting gold from hard rock is often a lot more difficult than processing placer gravels. Still, there is some very high-grade ore out there in many old mining areas.

What do you do when you’ve located a promising deposit of gold or gemstones, but it’s trapped in solid rock?

Most placer equipment is really made with gold in the 30 and larger mesh sizes in mind, though if carefully used can often get reasonable recovery down to the 50 mesh size.

There are three basic power sources for rock drills—electricity, gasoline and compressed air. Before we go into big pneumatic drills, we’ll start with a quick rundown of each.