Listed sites at a former Cornish tin mine shaft have been put on English Heritage's Buildings at Risk Register.
The complex is the focal point of a £30m regeneration scheme
English Heritage says the Grade II sites at the Robinson's Shaft complex, near the former South Crofty mine in Pool, are in a poor condition.
Houses for the compressor, boiler and pump engine, the carpenters' shop, workshops and forge have been added.
Also in Cornwall, the Insworke Chapel at Millbrook and Wheal Peevor monument were removed from the 2007 register.
South Crofty was the last working tin mine in Europe when it closed in 1998.
The Robinson's Shaft complex, which was once part of South Crofty, is the most complete surviving part of the mine.
Built in the early 1900s, it is under constant threat of vandalism and has been deemed by English Heritage as remarkable for its degree of preservation.
The carpenters' shop, sawmill, workshop and forge, built between 1903 and 1910, are not secure and deteriorating timber boarding is a cause for concern.
The 1903 boiler house is unroofed and internal machinery is at risk.
The compressor house is the only building still part-occupied.
The Robinson's Shaft complex is the focal point of a £30m regeneration scheme being promoted by Kerrier District Council and shortlisted for Big Lottery funding.
The Buildings at Risk Register is published annually and brings together information on all listed buildings and Scheduled Ancient Monuments known to English Heritage to be at-risk through neglect and decay.