Tertiary Minerals plc said that a new drill rig and variable ground conditions had made progress a little slower than expected at its Konkola West copper project in Zambia.
Operator Kobold Metals Company began drilling the first hole KWDD001 during April and reached a depth of 1,023 metres by 21 May.
The hole has now reached 1,341m and continues in the hanging wall sequence above the target horizon, added Tertiary.
Drilling will continue until the target horizon is reached while planning for a second drill hole has started.