Not all secondary deposits are the same, page-4

Yes but within the Maninge Nice they are mining primary rubies.

Actually what is more interesting is the minerisation of the two sites is very different to the point that they know the Maninge Nice is not the source of the secondary rubies.

For us what is more important is that if MUS were mining primary rubies we would not have a very good idea on the quality. Because they are mining secondary rubies we are very likely to be looking at the same resource and same quality.

In the GEM JORC they do mention that there is a negative correlation between yield and quality. MUS have been achieving lower yields per ton than GEM do out of their secondary sources so we might hope that we are getting better quality than GEM. I am not sure how much weight we can put on this now, but CJ did say in some tweet they were getting 80% gem quality out of the alpha deposit.