The Western Australia Branch of the Institute made a site visit to an industrial area near Perth on 17 July 2014. We were invited to inspect a new HPGR unit destined for the emerging iron ore producer, Top Iron. Its mine is east of Geraldton, Western Austrailan, some three hours drive north of Perth. Managing Director of Koeppern, the HPGR supplier, Andrew Gardula, showed us around the plant, and said that such relatively easy access made the supplier's job less stressful compared with many mine sites.
The unit was fabricated in Germany by Koppern and assembled in Perth by Koppern Machinery Australia Pty Ltd. The required thoughput of magnetite ore processing is modest, so only a small unit (about 90 tonnes) is to be supplied, capable of between 400 and 450 tonnes per hour. One of the important features of HPGR is that the rollers are not in direct contact with the ore but are protected by an autogenous rock layer considerably reducing wear and tear. The crushing is achieved by transient high pressure forces rather than rock being squeezed through a narrow metal to metal gap. These forces are transmitted through the tightly packed rocks, shattering the material along grain boundaries, simplifying subsequent mineral separation and increasing the production of fines and weakening the rock crystals. The energy saving compared to SAG or ball milling is about 15%, depending on the characteristics and water content of the feed material.
Honorary Secretary, IOM3 Western Australia Branch