Good summary. For those who want to learn more, here's a more in-depth reply to the "Are running out of Helium?" questions. I'll just quote the definition that

Good summary. For those who want to learn more, here's a more in-depth reply to the "Are running out of Helium?" questions. I'll just quote the definition that he uses, which in itself sheds light to teh matter: "a mineral reserve is that amount of some mineral that we have identified the location of, weighed, measured, tested the extraction of and proven (and the proof is the extremely important part here) that we can, with current technology, and at current prices, make a profit by extracting it." Perhaps a loose analogy would be with TAM/SAM/SOM.