Semafo reported in late June that follow-up drilling has more than doubled the strike length of the recently discovered Yaho gold zone 20 km south of the mill at its Mana operations in western Burkina Faso. Initial drilling identified a continuous strike length over a distance of 600 m. Follow-up drilling has extended the zone to the south and to the north and increased the total strike length to more than 1.5 km. The zone remains open on strike and at depth.
The Yaho zone is hosted by a clastic sedimentary unit that varies from a conglomerate to a quartz-rich sandstone. The conglomerate beds are polymictic, with abundant quartz-rich clasts and occasional rounded clasts of volcanic origin. The clastic unit is bounded by basaltic flows to the west and a sequence of fine graphitic sediments and volcanoclastics to the east. Alteration is constrained to the clastic unit and consists of strong, pervasive sericitization and silicification. Some quartz veining is also present, although not pervasive. Mineralization occurs as a series of stacked zones varying in widths of up to 19 m on the three newly drilled sections. Mineralization includes disseminated pyrite and arsenopyrite in varying amounts, ranging up to 5% to 10% locally.
Semafo has experienced significant delays in obtaining drill results due to substantial backlogs at the independent assay laboratories in Ouagadougou, the capital of Burkina Faso. Consequently, the company has decided to build an exploration laboratory at the Mana property. The new facility is expected to significantly reduce turnaround time for drilling assay results and to accelerate the reporting process.