Research scientists at the Geological Survey of Finland (GTK) have developed a process for disaggregating rock samples which, unlike traditional approaches, preserves the original morphology of mineral gains (main resposibility of the actual design was with the contracting civil engineers Markku Koivurova/Atol Avion Oy and Matti Rahkala/Rovaniemi Polytechnic). The process uses a Marx Generator (also known as a Sparks Unit) to transmit a short (<500 nanoseconds) high-voltage (>200 KV) electric shock into fist-sized rock samples. The samples are placed in a chamber formed from a bell-shaped top with a sieve on the base, which also form the electrodes.

Repeated shocks break the rock down along the boundaries of individual minerals. As the rock disaggregates, individual mineral grains fall through the sieve. According to GTK, the end result of the process is a sample composed of monomineralic fragments.

GTK says that the primary use of the technology is in peterological studies, noting that the EPD handles diamonds as any other mineral and that it has also been used in the study of platinum group minerals. GTK says that the advantages of the system include the preservation of mineral-grain morphology; a reduction in the production of fines/slimes; the preservation of the natural grain-size distribution; and allowing the concentration of target mineral fractions by sieving.

Contact:
Dr Markku Iljina
Geological Survey of Finland
Tel: +358 (0)205 504 213
Fax: 205 5014
markku.iljina@gsf.fi