Leakages and tree roots are damaging the viaduct
A £50,000 grant has been awarded by English Heritage to carry out a detailed survey of a 19th Century viaduct in Cornwall.
The Treffry Viaduct in the Luxulyan Valley near St Austell was built by Cornish engineer Joseph Thomas Treffry.
The massive granite structure was built to provide a horse-drawn tramway link to carry copper, china clay and granite from his nearby mines and quarries.
The scheduled monument last carried granite traffic in the 1930s.
The viaduct is 89ft (27m) high and 650ft (198m) long, with each of its 10 arches having a span of 40ft (14m) feet.
The structure, which also carried water to provide power for the Carmears Inclined Plane, forms part of the West Devon and Cornwall Mining World Heritage Site.
Rebecca Child, historic buildings architect for English Heritage, said Treffry was a symbol of Cornwall's mining and quarrying heritage and a monument to the county's engineering skills.
The English Heritage grant will help to pay for essential surveys of the viaduct.
"We hope this will enable proper repairs to be carried out which will ensure the viaduct's future for generations to come," Ms Child said.
Major structural repairs are needed because water and mature tree roots are damaging the viaduct.
The total cost of the work is £90,000 and funding is also being provided by Cornwall Heritage Trust, Cornwall Council and the West Devon and Cornwall Mining World Heritage Site.
Cornwall Heritage Trust said the funding would hopefully lead to the eventual restoration of an iconic structure of national importance.
The iconic granite viaduct was built in the middle of the 19th Century by Cornish engineer Joseph Treffry