Katoro Gold and Power Metal Resources said potential lithium and rare earths potential had been identified at their Haneti joint venture in Tanzania.
The Haneti exploration team had identified several pegmatite outcrops included within two abandoned artisanal pits.
The pegmatites consisted of coarse quartz, lepidolite, and red and black tourmaline.
Lepidolite contains significant lithium and its presence may be indicative of the presence of lithium minerals such as spodumene and petalite, the companies said.
The pegmatites could also prove prospective for rare earth elements as well as other exotic minerals such as tantalite-columbite.
Katoro owns 75% of the JV and Power Metal holds the remaining 25%. Power Metals has a right to increase to a 35% interest through a cash payment of £25k to Katoro, until 15 May 2020.
At 2:36pm: (LON:POW) share price was 0p at 0.55p