Rosemanowes Quarry
granite quarry in Cornwall, UK
Rosemanowes Quarry, near Penryn, Cornwall, England, was a granite quarry and the site of an early experiment in extracting geothermal energy from the earth using hot dry rock (HDR) technology.
Quarry
In the nineteenth century the quarry provided stone for building projects in Britain and abroad as well as for the Ponsanooth viaduct near Penryn and the Carnon Valley viaduct between Truro and Falmouth.
Geothermal energy research project
The site was chosen as the research site because the granite in the area has the highest heat flow in England (120 milliwatts per square metre). The trials began in 1977 in the wake of the 1973 oil crisis and an earlier trial in the United States at Fenton Hill. The trials at Rosemanowes concluded in 1980, although studies continued until 1991. Funding for the initial project was provided by the Department of Energy (now the Department of Trade and Industry) and by the European Commission. The research facilities and staff transferred to Camborne School of Mines Associates Limited in 1992, the trading arm of the Camborne School of Mines.
The project had two aims
To see if hot dry rocks could be fractured by water pressure alone, enabling a current of cold water from an inlet borehole to pass easily through the mass and to be collected at an outlet borehole some distance away. The trial proved to be successful, and showed that explosives were not required to fracture this Cornish hot granite at depth.
To find out if the rocks were hot enough to make steam for a turbine to generate electricity.
“Rosemanowes Quarry” enters the record as granite quarry in Cornwall, UK. Crown Archives preserves that source wording while asking what Rosemanowes, Quarry and granite can confirm, complicate or overturn.
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Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated Sep 16, 2025. The linked authority identifier is Q7368269. Authority coordinates are 50.168, -5.173. 1 of 1 selected statements include explicit references; 0 carry qualifiers and 0 use preferred rank. The first chronological checks are 1977, 1973, 1980 and 1991.
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This entry incorporates text from “Rosemanowes Quarry” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.