Gold is the 5th most abundant element on Earth – there is 455 million tonnes of it in the Earth core. But it is soluble in high pressure and temperature water. So as water comes up from the Earth's mantle, it is gold laden.
But as it get to under 34 meters from the surface, it precipitates out. But mining these gold deposits is expensive. South Africa now uses air conditioning to cool the rock, then chips it out. And separates out the gold at the surface.
Far simpler, use ground sonar to locate a mantel pocket. This will be shifted 2o from the river at a valley bottom. This is a guess – do some work hey!
We get the water up to the surface, and pass it through a double helical flow inverter: a Dyson made from stainless steel. We will get a constant precipitation of metal dust – as we drop the pressure to 7.8 bars: again do some work!
So we get an endless stream of heavy metal power, we sell on to process into ingots. 40% of it will be gold – just so much gold. Each plant will produce 20 tonnes of gold a year. $40,235,528.00 at today's prices. $40 million.
But the steam we use to generate power - $60 million annually. Carbon 0 electricity. With no fuel cost. For one little ground sonar and hole drilling.
Trouble is, man only has 2000 tonnes of gold. And we are going to do that every year, for ever. What are we going to do with it? Sea breaks comes to mind. And it will be cheaper than copper – so all wiring.