elvis-is-here- I wouldn't get too excited about this sentence "As far as they know currently, 45 of the kimberlites are diamondiferous and 30 of those contain macrodiamonds, which are stones with at least one side greater than 0.5 millimetre."
When I spoke to George Read, SG IR, he said that while the above is true, most of the kimberlites are NOT of economical value. That would then make most of the 10 B Tonnes of kimberlite meaningless. As for the macros to mean something, they have to find them in sufficient quantities. That is what they are now in the process of finding out.