Multi-million pound losses have forced the closure of a South Yorkshire coal mine after 90 years of production.
UK Coal faced geological problems at the Rossington site
UK Coal, Britain's biggest coal producer, closed its site at Rossington, near Doncaster, on Friday.
The company said £20m was needed to open up more reserves at the pit, but it could not finance the investment.
The Rossington pit once produced a million tonnes of coal a year and employed more than 1,000 miners but it has faced costly geological problems.
UK Coal chief executive Gerry Spindler said: "The men at Rossington have done an excellent job, often in geological conditions more difficult than any you experience in mining elsewhere in the world.
"There are still reserves remaining at Rossington, but they require a major investment which we just cannot finance at this time.
Remaining UK deep mines
Kellingley, West Yorks
Maltby, South Yorks
Daw Mill, near Coventry
"However, we will continue our efforts to identify a partner who is willing to underwrite the investment, though the options are limited."
Miners at Rossington will next week start the process of preparing for the recovery of equipment, much of which will be refurbished before being installed at other mines.
UK Coal announced last year that production at Rossington would cease, as its half-yearly losses reached £30.6m.
About 80 miners have left since then and most of the remaining 224 workers are expected to stay to recover equipment.
Rossington, which opened in 1915, was closed by British Coal in 1993 but was reopened the following year, since when it has produced 8.4 million tonnes of coal for industrial, domestic and power station use.
The Rossington closure leaves just seven deep mines in the whole of the UK. UK Coal has six other pits, while the seventh is in Tower in south Wales.