Aim-listed Hummingbird Resources' Yanfolila gold mine, in Mali, produced 23 807 oz of gold in the first quarter of this year, up 33% from the 17 895 oz produced in the fourth quarter of 2018.
Mining rates were, however, lower than expected.
"In the period, production was impacted by ore depletion from the Komana West pit from historical artisanal workings, which was greater than forecast in the reserve model. We are taking immediate steps to reverse the impact of this dilution through working closely with the mine contractor and, as we progress deeper in the pits, the impact of this is expected to reduce significantly in the near term as we access areas of expected higher-grade ore," CEO Dan Betts said on Tuesday.
Despite the lower-than-expected first-quarter output, Hummingbird is confident the mine will meet its full-year production guidance of 110 000 oz to 125 000 oz.
However, as a result of additional costs being incurred to deal with mining technique changes and plant availability, the full-year all-in sustaining cost may be higher than the previously guided $800/oz to $850/oz, the company warned.
Meanwhile, Betts said the company was looking forward to receiving an updated reserve/resources report in the second quarter, which would allow it to publish a new life-of-mine plan for Yanfolila.
"It is also pleasing to note the strong progress we have made on the second ball mill project and we look forward to the positive impact that will bring to our process plant capacity once completed," he added.
The construction of a second ball mill at the mine is on track for completion in the third quarter of this year.
The second ball mill will increase the processing plant's throughput capacity to 1.24-million tonnes a year, compared with the current one-million tonnes a year.