PERTH (miningweekly.com) – Mining major BHP has produced its first ore from the high-grade underground expansion at the Southern Mining Area (SMA) of its Olympic Dam operations, in South Australia.

The miner previously abandoned plans to expand its openpit operations at Olympic Dam, opting rather for an underground development pathway that could see copper production increase to 450 000 t/y from 2025.

Olympic Dam asset president Jacqui McGill said on Monday BHP was taking steps towards unlocking the potential of one of the world’s largest orebodies.

“The move into the SMA forms the foundation of Olympic Dam’s long-term expansion plans, and successful tests of the heap-leach copper extraction technology have the potential to support an increase in production to over 450 000 t of copper a year,” she said.

“We believe Olympic Dam can underpin jobs and economic development in South Australia for generations to come.

“An estimated A$250-million had been invested in the SMA expansion by the end of the 2017 financial year. A dedicated team of approximately 180 people have accelerated the development of the SMA over the past 15 months, and confirmation today of first ore is a testament to their hard work and commitment.”

Meanwhile, the miner also produced the first copper cathode from its heap leach trials, with McGill saying the heap leaching technology could revolutionise production at the Olympic Dam mine.

“Integrated heap-leach ore processing is a low-cost processing option being assessed for Olympic Dam to extract copper, uranium, gold and silver from our unique polymetallic orebody, and support our future growth plans in the state.”

A series of larger scale experiments and testing on the heap leach process are being undertaken over the next three years.

McGill said the milestones came on the back of BHP’s recent announcements of investment of around A$600-million this financial year to support underground development and upgrade surface processing facilities for long-term growth.

“Seeing the first output from the heap leach trials and from the SMA supports moving toward unlocking Olympic Dam’s potential and building a foundation for long-term, sustainable growth in South Australia.”