The future of a huge fertiliser mine in North Yorkshire will be decided later on Tuesday as shareholders decide whether to back a rescue takeover.
Many shareholders in Sirius Minerals are small investors who oppose the deal, saying it undervalues the firm.
But Sirius has warned it will fall into administration if a proposed takeover by Anglo American is not approved.
The firm blamed market conditions and Brexit uncertainty for its struggle to raise cash to help fund the mine.
The Yorkshire project is set to be the world's largest mine for polyhalite, a naturally occurring fertiliser which is used in agriculture. Due to open in 2021, it is expected to create more than 1,000 jobs.
The £405m takeover already has the approval of the board, but about 85,000 retail investors are expected to cast votes on Tuesday.
Many live locally and could suffer large losses from the deal, which values Sirus at 5.5p a share - less than a quarter of the 24p share price nine months ago.
'Locals were susceptible'
Andy Baldock, who recently sold his shares, told the BBC he had lost about £25,000, or a sixth of his pension pot.
"I'm disappointed in the way it's gone. This firm worked really hard to get the population on side - it was sold very hard to the local community who were susceptible because of the employment situation and the history of mining in the area," he said.
For mining giant Anglo American's bid to be successful, 75% of the shareholders must vote to approve the offer.
Sirius had hoped to raise $500m (£403m) via issuing bonds in September to allow it to borrow $2.5bn (£1.9bn). Sirius Minerals' share price has fallen by 58% over the past six months.
Many small private investors have clubbed together to try to find an alternative to Anglo American's deal.
But they also have support from hedge fund tycoon Crispin Odey, who has voted against the takeover, claiming that the 5.5p-a-share offer "does not represent fair value for shareholders in Sirius". Mr Odey's fund owns a 1.3% stake in Sirius.