The reason is that helium accumulates subterraneously in conjunction with natural gas over hundreds of millions of years as a consequence of decay of uranium and thorium. Once the easily recoverable global resources of natural gas have been exhausted, humanity will also have eliminated its supply ...
Malaysia. Mount Weld contains one of the largest and highest grade known deposits of rare earths. The deposit is additionally unusual because it contains very low levels of thorium, a radioactive contaminant commonly found
pollution, population, and food. It did not get into financial aspects to any significant extent, except where flows of resources indicated a problem–namely in providing investment capital. One thing the model did not include at all was debt. ...