There were significant performance improvements at Mothae following the plant and operational changes made at the beginning of 2023. Modifications made to the plant flow sheet and upgrades to the XRT (X-Ray Transmission) sorter eliminated the previous processing limitations related to hard ore.
Following the modifications to Mothae’s plant, capacity increased to exceed nameplate by 30 percent. A mobile crusher which reduced the need for oversize blasting and rock breaking, was also deployed in Q3 and had a positive impact on the plant throughput as it reduced the amount of over-sized material delivered to the primary crusher.
Mothae set new annual records for tonnes mined and processed, carats recovered and average price per carat. More than 2.34 million tonnes of ore and waste was mined in 2023, up 23 percent from the previous year, while 1,468,909 tonnes of ore was processed through the plant, up 22 percent on 2022.
Mothae recovered 32,884 carats in 2023. This was an increase of 7 percent compared with 2022. Production included 219 Special sized diamonds of +10.8 carats, 11 percent higher than the previous year. The largest diamond recovered in 2023 weighed 86 carats and several fancy pinks and yellow coloured diamonds were recovered. Rough diamond revenue of US$24.9 million was 13% higher than the previous year.
From Q1 to Q3, the value of stones recovered from Mothae was in line with expectations. However, in Q4, the size and quality of the diamonds declined as the lower-quality Type I stones dominated recoveries. This in turn sent the average price per carat achieved in Q4 lower to US$541 per carat from US$896 in Q3.
The average price per carat achieved for Mothae production for the full year was US$775, 12 percent higher than the previous year, however approximately 20 percent lower than guidance for 2023.
