Hi Mike-- while I'm certainly no expert, the fragmentation discussed occurs in the RC (reverse circulation) drilling, which, to my knowledge, is usually 2-3" and less, in DE. This was what Ashton used for first stage drilling. How can a diamond become shards, you ask, if it's the hardest substance on earth known to man? Read the following and it should easily clear that up for you:
amnh.org
(cleavage)
As you point out, the larger diam.core drills, commonly used for minibulk and bulk sampling, will have less damaging effect on the matter at hand, since more of the substance extracted is left in tact.
-Gotta Run-
Cheers,
-j
:>
ps, I assume the larger the core the better the sample for assay and interpretation |
