I think there’s different ways: - take random samples from the area and statistically come up with that value - put a radar/sonar/ xray etc in a hole and get an

I think there’s different ways: - take random samples from the area and statistically come up with that value - put a radar/sonar/ xray etc in a hole and get an outline of how big the deposit is. I did not work in this field explicitly, but worked on Gaussian processes which were first used as a way to aggregate data like this from multiple sources to minimize the number of drillings required to find oil.