I'm assuming it's not a giant 15M ton chunk of (highly reactive) metal in the ground, but rather they took a bucket of dirt, analyzed it, and extrapolated how much lithium is available in the ground. My question is, how much "earth" do they need to dig up and refine to extract this amount of lithium?
from what i can see the media/government minister have blown this out of proportion.
First off it looks like they identified 15M tonnes of lithium hosting rock (pegmatite) which has a grade of 0.4% of lithium in the form of spodumene (which then needs ot be processed to extract the lithium out of).
But in general, how it works is they drill a bunch of holes in the ground and analyse the cores. From that that interpolate the size/shape of the ore body and calculate an estimate of size.
The more holes they drill the greater the confidence.
Rocks tend to be 5-10x denser than water, so assume 2 million cube meters. That is just 2 square kilometers 1 meter high, so not mountains or so. As a comparison, for a large iron mine they dig up many billions of tons of rock, and that is for very cheap iron, so you wouldn't need a very large operation to dig this up.
Normally an announcement like this would be based on a program of drilling. But yes there would be a lot of interpolation and I think some extrapolation.
