Good luck extracting all the Thorium and Uranium from an average rock and refining it sufficiently to fuel a nuclear reactor.
Without understanding anything about it, it's natural to assume it must be difficult. Otherwise, why wouldn't more people be doing it? As noted in the article, coal mostly sat in the ground for thousands of years before 1750, when all of a sudden mining it was the obvious thing to do. Why?
Define "average rock," and cite a source for this factoid, please? I'd never heard anything of the sort.
...While you're at it, define "incredibly easy." I'd gathered that thorium fission was still a hard problem.
Average crustal abundance 10ppm * 2.6g/cm^3 * 1m^3 = 26g
26g * 8e16 J/t ≈ 2.6t * 1200ΔC * 0.79J/gΔC * 1000
How did you gather that?
The author apparently doesn't know that fissioning the thorium and uranium in an average rock yields 1,000 times the energy needed to melt it.[1] The ground you walk on is literally beaming with energy, and it's incredibly easy to have out.
[1] 2000 GJ and 2 GJ per cubic meter, respectively.