Nullagine Achieves Production Run-rate Ahead of Schedule
Over the past two weeks, daily production from Nullagine has averaged approximately 400 oz/d, including record daily production of 540 oz of gold on August 30. Millennium had expected to achieve an annualized run-rate of 100,000 oz/y in the fourth quarter, however, a strong production performance over the past two weeks has enabled the company to achieve this goal ahead of schedule.
The increase in gold production is mainly driven by a higher average head grade as the new Bartons underground and higher grade open-pit ore are brought online, supported by an increased mining rate and materially improved mill throughput — all of which are expected to be maintained over the remainder of 2018 and into 2019, the company said. Ore feed at Nullagine is currently still being blended with low-grade ore from the pre-strip of the Golden Eagle deposit, which is now almost completed, indicating that further increases in head grade could yet be achieved.
Millennium CEO Peter Cash said the outstanding production performance justified the company’s strategy of targeting larger, more sustainable ore sources at Nullagine while also demonstrating the significant impact of introducing higher grade ore to the plant.
“We have put in a huge amount of ground-work over the first half of this year to establish these high-grade ore sources, and to have achieved our annualized production target ahead of schedule is a great credit to the team,” Cash said.
The mining rate at Nullagine has risen from a monthly average of approximately 400,000 bank cubic meters (BCM) for the first six months of 2018, to more than 600,000 BCM over the past two months. This increase has been achieved by employing more efficient mining strategies in its open pits, delivering a strong boost to productivity without the need to employ any additional equipment. The Bartons underground development in August increased to more than 400 m with one jumbo drill.
Mill throughput has lifted from a monthly average of 154,000 mt over the first six months to 175,000 mt over the last two months through the implementation of a number of improvement projects including optimization of the SAG mill performance through process control enhancements and changes to mill liner design.
Collectively, these enhancements have put the Millennium on-track to achieve its forecast production guidance of 20,000 to 22,000 oz in the third quarter, and 25,000 oz in the fourth quarter.