We use a Hammermill kit. Our main case was a large data set on heavy minerals tracing. It did well with RC cuttings. For cores, we used direct shoots on the split face, as we had no intention of quantifying resources - we were after mapping layers or levels.

However, the Hammermill is more suitable for scattered field samples, milled in the boot of a car, than for large numbers of core or cuttings samples. Despite its good build quality, it has a very limited throughput. When submitted to heavy sample loads, the small engine may overheat, and the hammers wear quickly.

On a drilling site, it might be more efficient to use a small benchtop unit, as 110/220V supply is usually available. 

Thanks for the feedback. Some years ago (talking mid 1980s!) I had the job as sampler grinding 2 m long samples from drill cores on a base metal project. The tool that was used was a diamond encrusted wheel with a rounded head that was set into a bench and could be adjusted so as to grind a reasonably large groove from the side of the core. The product was a coarse powder which could then be sent off for assay. These days could be milled pretty quickly and an onsite portable XRF read or two would be useful for first pass sample selection and I expect would also help with logging.

I recall the grinder was pretty quick, save and appeared to be reliable to sort out the chaff from the seeds in zones of disseminated mineralization. The method also left plenty of cores to be cut for follow up 'correct' samples. Interestingly I went looking for the device recently under the misapprehension that this must be a commercial tool that people would still be using widely in the industry but was surprised to find that no such thing existed on the net, other than a reference in Roger Marjoribanks excellent book on exploration (see image page 58 http://is.gd/yBOTYo). Somebody else found the reference to the direct rock sampler - but this does not seem to be as good as the grinder I was using all those years ago.

I believe that this may be the "Core Grinder" you are looking for / referring too? -http://is.gd/FzOQGc It is manufactured in South Africa and is similar in make to the Almonte Core Saws. I have a full PDF product brochure.

With respect to the Direct Rock Sampler - it is now available from the OEM Company called Bear Claw Scientific.
I have heard that it does work quite well, but the OHS issues around dry grinding make it an issue for most companies. You also need a well trained sampler to ensure you are getting a good consistent cross section and not destroying your expensive and valuable drill core!

These are nice prototypes worth of small scale industrialization in many labs! We might talk further about yours; I may have the right contacts. 

Thanks I suspect this is what I'm looking for - do you know if there are any suppliers in Oz? If you could put a link up to the flier that would be helpful.

I have not yet bought this clever tool (a battery grinder fitted with a dust collector) but this obviously something that may allow more representative rock analysis on field than direct shooting.

Compared representativity, grain size and contamination issues would be a nice subject for discussion.