Zinc-focused base metals company Trevali has reported that recent drilling at its Perkoa mine, in Burkina Faso, confirms mineralisation remains open at depth, after drilling 240 m below the current modelled mining level.

The company said in a drilling exploration update on Wednesday that, since acquiring Perkoa, a re-interpretation of the geological model has recognised the significance of structural thickening of the deposit on an approximately 200 m periodicity.

The recent deep drilling has, for the first time, identified an emerging feeder zone, a common feature of volcanogenic massive sulphide (VMS) ore deposits, comprising chlorite-magnetite alteration and increasing abundance of copper mineralisation.

Mineral system analysis indicates that exploration is vectoring towards the higher temperature part of the system, suggesting that there is significant remaining depth potential for the discovery of additional resources.

“Integrated regional exploration of the Perkoa mine horizon is progressing well. In detail, ground time-domain electromagnetic geophysical surveys, air core drilling, surface geochemical sampling and mapping, are continuing to identify new unexplored geophysical and geochemical anomalies along strike from Perkoa along the postulated trace of the productive mine horizon,” the company said.

Trevali further noted that mapping and surface sampling have identified previously unknown gossan outcrops, and follow-up trenching and channel sampling has revealed these leached rocks to be anomalous in base metals, reporting similar elevated trace elements to the Perkoa discovery gossan.

“These will be drill tested in the coming months, and clearly demonstrate the exploration potential of this unexplored frontier VMS belt.”

The company also announced that it had increased beneficial ownership of its majority-owned subsidiary Rosh Pinah Zinc Corporation (RPZC), in Namibia, from 80% to 90%, owing to a partial share buy-back of issued RPZC shares under agreements with its Namibian shareholders.