That's correct, and Asia-India currently gets most of their FeNb...

That's correct, and Asia-India currently gets most of their FeNb from CBMM because CBMM is 90% of the market. I like the FeNb market set-up for WA1 very much and posted it back in that link (positive analysis yet most can only see through he suspicious lens I'm a downramper).

If the FeNb market was evenly split between 10 producers, no monopoly swing producer would exist and every producer needs to keep production at max nameplate to keep costs low or go out of business. Then WA1 is faced with pushing into a competitive supply market with no reduction capacity without pushing someone out of business, which means a price war against producers without debt, and equity investors required to get WA1 funded would know that and not want to risk their money investing into a imminent price war that either sends WA1 broke because of the large debt carry, or WA1 survive but the share price is smashed over a few ugly years of low prices while the war rages (think lithium 2018-19).

The CBMM monopoly is very good for WA1 at 15Ktpa FeNb, which they will allow into the market and take a short term hit (excluding demand growth potential for the moment). If two new producers want to enter same time for 30Ktpa extra supply, maybe CBMM isn;t happy to take that size sales hit and fights back on price, especially if Nb demand growth fails to take off.