I spoke to an exploration professional and he informed me that companies are using a portable XRF (X-Ray Flourescene) analyzer and recorder which cost about $50,000 to measure grades for Ni and Cu in core. It is accurate in homogeneious materials where grade is fairly consistent but where large crystals or varying grades occur, it is naturally less accurate. Apparantly there are mining companies in Austrailia who are reporting readings from this instument.

Obviously, there is technology available onsite to give fairly reliable indications of Ni/Cu. Now rumours can be sourced from analytical information rather than just visuals by drillers and onsite geologists.