Much of the material we receive is already finely ground and ready for XRD or XRF analysis, but sometimes we receive bulk material which must be homogenized before we can take a representative split for analysis. This is one of the most frustrating parts of working with samples and very time-consuming as we’ve historically done it by hand. This usually means splitting out a large fraction of the material and breaking up larger rocks, etc by hand, sieving, then breaking again, then sieving, etc until we have a somewhat uniform particle size that can be split with some confidence that it is homogenous.
Looking at coarse crushers brings us into the world of large-scale mining exploration even on the laboratory side. These machines are designed to process a very large amount of material and contamination is not a primary concern. Fabricating our own tool was definitely a possibility, but we recently came across the OLESI orbital crusher. It’s small, inexpensive, and while it’s still designed for more material than we would generally use, it seems very capable of running small batches of a few kg.
The unit is designed to sit on top of a 5-gallon bucket, but it’s likely that we’ll fabricate a small base with a pull-out drawer to retrieve the material. We specified the AC motor-driven version, but there is also a 12V version for fieldwork. The first test was a batch of bauxite ore we received a few months ago. This material had sandy components, but also hard rocks of a different mineralogical makeup. Everything needed to be homogenized before we could hope to take a representative split. The OLESI 4 crushed all but the largest pieces which were easy enough to break up with a hammer before feeding. I attached a plastic bag to the bottom (inside the bucket) to catch the product.
The OLESI line is sold by Goldbelt Global which sounds like it would be an imported product, but it turns out that this is made in the USA. Support, spare parts, etc is all domestic.