The AIM-listed company (HUM) has been treading water on the market in the past 12 months as it sought to boost operational performance at Yanfolila, which started production at the end of 2017, to take advantage of stronger gold prices. It aims to lift output next year to 130,000ozpa from the 110-125,000ozs targeted this year based on higher plant throughput in the current half from a second ball mill installation.

Yanfolila's June quarter production of 27,466oz was up 15% on the first quarter, with AISC of US$998/oz 23% down on the $1,297/oz in the first three months of the year as average head grades rose 16% to 2.86gpt. The mine started with pre-production reserves of 710,535ozs grading 3.14gpt, and about 1.8Moz of total resources.

Hummingbird is more closely studying underground mine economics with a view to further sweetening milled grades and lifting production, based on a current modest underground reserve inventory that could grow in future.

"The company is pleased to report a steadily improving operational performance in Q2," CEO Dan Betts said.

"The issues previously communicated which adversely affected production in Q1 have largely been addressed and this has translated into an improved production profile. April saw 7,582 ozs produced with May and June returning to circa-10,000oz/month.

"Costs have been reducing, grade increasing, and volumes mined and processed have both increased resulting in almost 200,000 tonnes of ore on the ROM at the current time.

"In the last few weeks, post quarter end, we have seen the second ball mill being commissioned. The mill is currently ramping up and has already experienced periods operating at design throughput. This will materially increase our ability to process more ore against the original design parameters as we move down the pits into predominantly fresh and harder material."