Ann: 41 Diamonds Recovered From Lulo Kimberlite L164 Bulk Sample, page-5

Proof! For all the talk, there is finally tangible proof that at least one kimberlite hosts the source to the alluvials. Now, the credibility has jumped considerably.

With multiple host sources suggested, now the stress is off (with the first one found), and we can keep methodically checking the rest. I wouldn't be surprised if the bulk sample gave them more information, of which other ones are most likely to be the same, and thus speed up the discovery rate.