I'm going to go out on a rather small limb here, and suggest that neither the Bloomberg article
NOR Mr Musk is correct wrt the graphite brouhaha.
My mining background does not include graphite/plumbago specifically, but I know something about the material generally.
China does produce a goodly amount of the world's graphite. Of the three types of primary sources, almost all Chinese graphite occurs as a difficult-to-work fine-grained (powdery) substance and, indeed, it is easy to envision its processing as being conducive to air pollution (as an aside, probably less than an asterisk in China's air pollution problems, but that's not the issue here).
Other sources of graphite - Brazilian, for example - mine occurrences of lump or flake graphite; the processing of which is a far, far less dusty process than working the powdered form. In the United States and in Japan, almost all graphite is formed from coke, a waste product from a varieties of smelting activities. So if Mr Musk is correct in citing Japan as its graphite source, it's very likely not to have been mined, but is synthetic graphite.
Now, China
does produce most of the world's graphite - about two-thirds, or about ten times what the US now manufactures. Not all that graphite goes into your "lead" pencil - most assuredly, some goes into batteries. It's not a stretch to conjecture that if a battery is made in China, it's using Chinese graphite. But if the battery is Japanese - synthetic graphite is a likely component (thus my suggestion that Mr Musk may be wrong).
Lastly, and again as an aside, effectively all graphite
began its cycle in the same way oil and coal did - as organic carbon (those famous "dinosaurs", donchaknow?
). Coal, subjected to intense pressures and temperatures, has its carbon reduced to graphite. If there were some way for a coal bed to be subducted to ridiculous depths in the earth - very unlikely - then not graphite, but diamond, might be the result. But now I really digress.
On edit: It is difficult - a euphemism for "impossible" - for any even moderately complex manufacturing process to ensure unequivocally that every last one of its materials, labor, and capital inputs are "green"/"socially acceptable"/"good". It doesn't take but a moment's thought to realize that your criteria differ from my criteria and are antithetical to the criteria of that guy over there.
HOWEVER, one can set one's own criteria and attempt to meet them. The issue on the table here
suggests that TMInc. may wish to ensure that the graphite used to create the anodes in its battery Gigafactory be definitively sourced from synthetic graphite (and, for chauvinistic sentiments, US or possibly Japanese-derived syn-graphite...but I'm not going to go there any more than that one line).