Shares in Tungsten West PLC fell 16% to 25p after the company launched a fundraising of at least £43 million to support the restart of production at its Hemerdon mine in Devon.
The company has secured £29.3 million from a new international investor via a direct subscription.
It is also targeting up to £11 million from an institutional placing and a further £3 million from retail investors.
Shares are being offered at 18p each. This was a 39% discount to the previous closing price after the shares shot to a three-and-a-half-year high earlier this week after the company revealed a sharp uplift in project economics.
The offer price is a 10% premium to the 30-day average prices.
The company said the proceeds would be used alongside project debt financing to deliver a feasibility study, repay a £2 million bridge facility, and prepare for early-stage commissioning in the second half of 2026.
Full production is targeted by late 2027, with Hermerdon seen as one of the largest tungsten and tin resources in Europe, one of the few sources of tungsten outside China, amidst surging demand from the defence and aerospace sectors.
Chief executive Jeffery Court said: "We are very pleased to open our equity raise to commence the formal fundraising part of restarting operations at Hemerdon."
Earlier in the week, he noted that since releasing the project's updated Feasibility Study in August 2025, tungsten prices have increased over 200% and tin prices over 70%.
Using updated market prices, a forecast net present value of the project has jumped from $190 million to $1.7 billion, with the internal rate of return increasing from 29% to 197%.
Debt funding was said to be progressing well, with several potential lenders at the term sheet stage.