The Morwellham Quay museum and visitor centre is seeking private investors, after entering administration.
Devon County Council has refused to give more funding to the Morwellham and Tamar Valley Trust, which owns the museum, leading to the appointment of Grant Thornton as administrators.
The 150-acre mining museum opened near Tavistock in 1970 and attracted 150,000 visitors a year at its peak. This fell to 40,000 in 2007 while building work was undertaken, but recovered to 53,000 last year.
Devon County Council previously rescued Morwellham Quay from the threat of insolvency in 2006, loaning it £1.2m. Another £200,000 was advanced this summer on condition that a "credible" business plan was received.
But the council said that as a workable plan had not been submitted, no new funds would be provided, although it would not ask for immediate repayment of the original funds.
Council leader John Hart said: "It will now be up to the trust how it proceeds, but it will be its decision."
Limited opening this winter was planned for school parties, but a museum spokesman said: "We don't know what is happening."
A Grant Thornton spokesman said the museum's operation was "being reviewed on a weekly basis". He added that the museum's debts and future were still being assessed.
Devon County Council has refused to give more funding to the Morwellham and Tamar Valley Trust, which owns the museum, leading to the appointment of Grant Thornton as administrators.
The 150-acre mining museum opened near Tavistock in 1970 and attracted 150,000 visitors a year at its peak. This fell to 40,000 in 2007 while building work was undertaken, but recovered to 53,000 last year.
Devon County Council previously rescued Morwellham Quay from the threat of insolvency in 2006, loaning it £1.2m. Another £200,000 was advanced this summer on condition that a "credible" business plan was received.
But the council said that as a workable plan had not been submitted, no new funds would be provided, although it would not ask for immediate repayment of the original funds.
Council leader John Hart said: "It will now be up to the trust how it proceeds, but it will be its decision."
Limited opening this winter was planned for school parties, but a museum spokesman said: "We don't know what is happening."
A Grant Thornton spokesman said the museum's operation was "being reviewed on a weekly basis". He added that the museum's debts and future were still being assessed.
