RE:RE:Root cause
Processing
During the three months ended December 31, 2023, a total of 2.1 million tonnes of ore was stacked on the HLF at a throughput rate of 22.3 k tpd. A total of 1.4 million tonnes of ore was stacked on the HLF at a throughput rate of 14.8 k tpd for the prior comparable period in 2022.
Ore stacked on the HLF increased by 51% for the three months ended December 31, 2023. In Q4 of 2022, the operations experienced a belt splice failure resulting in approximately 18 days of lost production. In addition, there was a period of extreme cold temperatures where operations were curtailed for 6 days (see 2022 Q4 MD&A). During the most recent period, these challenges were not encountered, and coupled with reliability improvements seen over 2023, resulted in stacking rate improvements.
Ore stacked for the quarter had an average grade of 0.65 g/t Au, compared to 0.90 g/t Au in the prior comparable period in 2022. Although grade was expected to be lower due to mine sequencing, the grade was also impacted by the stacking of lower grade bonus ore (material outside of the mine plan above cut off grade) and the processing of lower grade stockpiles.
During the year ended December 31, 2023, a total of 9.0 million tonnes of ore was stacked on the HLF at a throughput rate of 24.6 k tpd. A total of 6.6 million tonnes of ore was stacked on the HLF at a throughput rate of 18.1 k tpd for the prior comparable period in 2022.
Ore stacked on the HLF increased by 36% for year ended December 31, 2023 primarily due to successful implementation of year-round stacking as well as the above noted challenges in 2022 that did not impact 2023. Crusher utilization in 2023 improved by 30% over 2022.
Ore stacked for the year ended December 31, 2023 had an average grade of 0.72 g/t Au, compared to 0.85 g/t Au in the prior comparable period in 2022. The grade difference is primarily due to mine sequencing coupled with the stacking of lower grade bonus ore and stockpile material.
As at December 31, 2023, the Company estimates there are 86,073 recoverable oz within mineral inventory.