if we are talking 0.2t from 90t, then that is a very small yield...

if we are talking 0.2t from 90t, then that is a very small yield of that high quality stuff. But it is not possible to know if that is derived from a smaller proportion of the sample, or if it took a concerted effort processing the whole lot to get this.

I think it is an obvious question to expect answered in such an announcement, as we need to be able to estimate some economics. So the lack of that info may be telling as well, assuming not enough info has been provided to calc this.