McArthur River’s mineral footprint indicate undiscovered, high-grade zinc deposits

Based on a CSIRO study of existing drill holes around the McArthur River zinc mine in the Northern Territory, the geology of the area is replicated in older rock underneath. For the researchers, it was evidence of similar geological processes that happened millions of year before the rocks were deposited on top of the McArthur River.

These mineral footprints could be an indicator of high-grade zinc deposits waiting to be discovered, CSIRO scientists say. Because of this lead, Armour Energy, a junior explorer and collaborator in the study, would expand the exploration programme further.

New zinc discoveries, even if bulk commodity prices have been falling, are still welcome developments in Australia’s mining industry. New finds could fill in the gap in the supply hole and boost the country’s sagging minerals and mining industry hit by falling prices and demand in the international market.

To drive the next wave of discoveries, says Dr Sam Spinks, lead study author of CSIRO, the agency would focus its research efforts on under-explored areas and those with surface over. It would continue using state-of-the art x-ray techniques at its Advanced Resources Characterisation Facility to gain a better understanding of rock mineralogy. The information it gets is combined with geochemical models which show how the zinc deposits were formed. The study was published in Ore Geology Reviews.

Spinks admits no deposits have been found yet, however, the metal haloes in the rocks and high zinc concentrations in the area are considered by geologists as distal footprints of potential metal mineralisation. The team studies those processes that lead to deposits formation which is vital in greenfield exploration.

Following those steps lead to more targeted exploration drilling which helps miners save costs while cutting impact on the environment. For more than 130 years, Australia was a leading global producer of zinc, but the closure of Century mine in 2015 slowed down the zinc sector.

Zinc is used for various products and processes, such as galvanizing steel and in advanced technologies. According to Metal Miner, because of the seven-year low zinc prices, Horsehead Holding temporarily stopped production at its zinc smelter plant in North Carolina. Before 2015 ended, zinc price was near the $0.70 (AUD$0.97) level, down from the peak of almost $1.10 (AUD$1.52) per pound in May.