Mining

Comminution of rocks to liberate target minerals is the single greatest energy requirement of the mining industry, and even small reductions in energy usage have the potential for large economic gains. With an increasing drive towards energy efficiency, SELFRAG high voltage pulse systems offer several advantage to mineral processing operations, including the early removal of gangue and the selective fracturing of hard ores. The former reduces transportation costs and increases grade, while the latter makes the ore softer to reduce milling time and media wear, while dramatically increasing surface area and therefore leaching potential.

Because of its selectivity all minerals are liberated in their natural occurring sizes. This enables to remove gangue at early stage and reduce mass flows. SELFRAG systems liberate metallic particles at overall coarser sizes than traditional mining, removing the need to mill all of the ore to the size of the target. The early separation of ore from gangue allows pre concentration of the ore, and reduces transportation of low value material. The reduced fine production of high voltage fragmentation reduces the potential losses ore to tailings. 

 

The SELFRAG Scoria system

 

Improving Ore Grindability

By reducing the treatment energy, SELFRAG systems can fracture a material instead of fully fragmenting it. This introduction of microcracks into an ore is called ‘pre-weakening’ and significantly improves ore grindability, offering up to  50% increase in JKMRC A*b value and a 25% decrease in the BWI. SELFRAG Can optimise this process to reduce grinding energy consumption and wear of grinding media, or increase mill throughput by up to 30%.

 

Porphyry ores weakened by high voltage discharge

 

The SELFRAG process is able to produce a dense network of micro-cracks along grain boundaries. The effective creation of sufficient pathways for leaching agents improves the leaching performance. Even encapsulated particles like Au or Ag in pyrites or silicates can be exposed thanks to SELFRAG. The fractures introduced by high voltage pulse treatment occurs at the contact between ore and gangue, exposing additional metallic ore surface area to leach solutions.