Police are appealing for information following a fire at Navigation Colliery in Crumlin on Saturday, June 30.
Police were called to the site at around 9.30pm after reports that two portacabins were on fire.
The cause of the fire has not yet been established and officers are investigating.
Despite the attendance of South Wales Fire and Rescue, both portacabins, that are used by a voluntary conservation organisation, were badly damaged.
A statement on the ‘Friends of The Navigation’ website said: “Everything in the storage cabin and the cabin itself has been lost.
“This included a display board constructed over many hours by one of our volunteers, various items relating to the Oral History Project, tables used for our markets, tools, and health and safety items.”
“We are in the process of a clean-up, and any help you can give would be appreciated. You can contact us on our Facebook page.”
Anyone with any information about this incident can call Gwent Police on 101 quoting log number 704 30/6/18.