The veins are made in the process, thought the gold itself was already present in the water which was vaporized due to the pressure of earthquake
"""In 1980, he transmuted several thousand atoms of bismuth-209 into gold (197 Au) at the Lawrence Berkeley Laboratory. His experimental technique, using the lab's Bevalac particle accelerator, was able to remove protons and neutrons from the bismuth atoms by bombarding it with carbon and neon nuclei traveling near the speed of light.[47] Seaborg's technique would have been far too expensive to enable routine manufacturing of gold, but his work was close to the mythical Philosopher's Stone.[48][49] As gold has four fewer protons and (taking the only naturally occurring bulk isotopes of either) eight fewer neutrons than bismuth, a total of twelve nucleons have to be removed from the bismuth nucleus to produce gold using Seaborg's method."""
the building where plutonium was first synthesized still exists ont he berkeley campus although IIRC they had to clean it up: https://en.wikipedia.org/wiki/Gilman_Hall#Room_307
There's a critical distinction between the abundance of chemical elements within Earth's crust and how, where, and when they are concentrated. I'm not generally familiar with the topic, but of a few instances:
- Most iron ore is of biological origin, with so-called "banded iron formations" (BIFs) being largely formed in two episodes, ~3 billion and 1 billion years ago, largely by early bacteria.
- "Rare earths" aren't so much rare as unconcentrated. By overall abundance, these are fairly common, but because they do not form ores, they're found at low concentrations, and are often recovered as by-products of other mining activities.
Keep in mind that the issue of ore formation and its reliance on processes specific to Earth's geological evolution, including plate tectonics and biological activity, mean that prospects for mining on other worlds (the Moon, Mars, asteroids) are likely to face radically different circumstances. Then again, mining in such areas would also likely be focused strongly on substances considered generally abundant on Earth, such as oxygen and water.