Helium One Global has increased the size of an ongoing fundraise to approximately £9.9mln due to what it said was significant demand for the share issue.
Last night, the junior said it wanted to raise a minimum of £7mln but added today that it had upped the amount due to the strong interest.
The funds will provide greater financial flexibility for its 2023 drilling programme in Tanzania, it added.
Shares were issued at 5p per share, a 26% discount to the close on 12 December 2022.
Earlier this month, Helium One said it was on track to spud a well at the Tai prospect on its Rukwa licence in Tanzania in the first quarter of next year.
David Minchin, chief executive, added: "Capital raised through the proposed fundraising will allow the company to progress its Phase II exploration drilling.
“A discovery made at Tai will help to unlock the value of our entire portfolio and help grow the company into a strategic player in developing a new supply in this high-value, high-demand, high-tech commodity."