In old California you didn't cry Eurkea if you found gold, you just looked quietly over your shoulder to see if anyone saw you and would report you to the government. Then you kept it a closely guarded family secret.

Okay, say a rancher notices a good show of gold in a stream, and he does as you suggest. He pans a few ounces now and again, hoping nobody notices. Along comes a prospector who discovers the same gold in the stream. He already knows what claims are staked in the area and when he discovers that there is no claim on that stream, he's gonna stake his claim and go to work. The rancher shows back up to his favorite panning spot to find a massive sluce operation going on. Tough luck, buddy. And he better not try to jump the claim, or commit mineral trespass. That sort of behavior usually ended in gun fire.

Gold discoveries have a way of leaking out no matter how closely guarded the secret. It's part of "gold fever".

No. In California there were what is known as a staking rush...prospectors pour into an area and stake damn near every square inch of ground. Investors come in to try and buy good claims to consolidate them. There is no way you are going to hide even a small mine in a hot district.

(more wiki reading Gold Rush and California Gold Rush)

As you can read in the second article, Mexico did have a system of staking mineral rights. I'm still looking for a good reference that covers those laws.

And I agree, Capitalism enhances mineral exploitation. But Empires and Caliphates and Dynasties were all pretty good at discovery and mining as well. The Romans were excellent miners, as were the Egyptians and the Chineese.

Sorry, must get back to work, got gold to find.