I understand that mineral rights and surface rights can be separated. I should have mentioned that, as many people are unaware of the fact. What I was highlighting was that in the US individuals and/or companies own property rights to sub-surface minerals below private land, not the government, unlike most countries.

People in the US can still claim federal land in the US for basically free, if they are going to mine productive minerals due to The General Mining Act of 1872[1]. Oil and coal leases are different and the government takes a 8%-12.5% royalty. Still not very much. Most of the value goes to a large number of people in the country, not to the government.

[1]https://en.wikipedia.org/wiki/General_Mining_Act_of_1872