Mortar outcrop at Trenear, 9m north east of Poldark Mine entrance
Listed on the National Heritage List for England. Search over 400,000 listed places
Overview
- Heritage Category:
- Scheduled Monument
- List Entry Number:
- 1021409
- Date first listed:
- 19-Oct-2009
Location
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Images of England Project
- Date:
- 2000-06-17
- Reference:
- IOE01/00005/02
- Rights:
- © Mr Alan Whitcroft. Source: Historic England Archive
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Discover moreOfficial list entry
- Heritage Category:
- Scheduled Monument
- List Entry Number:
- 1021409
- Date first listed:
- 19-Oct-2009
Location
The building or site itself may lie within the boundary of more than one authority.
- District:
- Cornwall (Unitary Authority)
- Parish:
- Wendron
- National Grid Reference:
- SW 68339 31568
Reasons for Designation
The mortar outcrop at Trenear, 9m north east of Poldark Mine entrance is the only known example of an early hand tin-crushing site in the South West of England. The outcrop survives very well because it has until recently been protected by a layer of soil, which may also preserve rich environmental and archaeological information; particularly in the area adjacent to the southern edge of the rock.
Details
The monument includes a large earthfast slab of granite with at least 17 circular or oval shaped hollows, here argued to have been ore-grinding mortars, worn into its upper face. The site lies within the 'Cornwall and West Devon Mining Landscape' World Heritage Site, site No. 17. The mortar outcrop is situated on the northern edge of the floodplain associated with the River Cober. The hollows are similar to those found on mortar stones associated with tin stamping mills, but their disposition precludes mechanical formation. The hollows vary considerably in size and depth with the largest one being 22cm long by 20cm wide and 10cm deep. The interior of all the hollows are worn smooth as a result of the crushing process. The hollows are all situated along the southern part of the outcrop and were formed by hand crushing of tin ore from the nearby alluvial streamwork. Hand crushing of ore is considered to have been carried out in Cornwall before stamping machinery was introduced during the medieval period. Using field evidence alone the precise dating of this tin ore crushing site is not possible. It would, however, fit most comfortably into the later prehistoric period when particularly rich ore recovered from the adjacent streamwork could have been economically crushed by hand. The modern barrier erected to prevent vehicles straying onto the monument is excluded from the scheduling, but the ground beneath is included.
MAP EXTRACT The site of the monument is shown on the attached map extract.
Legacy
The contents of this record have been generated from a legacy data system.
- Legacy System number:
- 36032
- Legacy System:
- RSM
Sources
Other
Fieldwork by S. Gerrard, Gerrard, S., (2004)
Legal
This monument is scheduled under the Ancient Monuments and Archaeological Areas Act 1979 as amended as it appears to the Secretary of State to be of national importance. This entry is a copy, the original is held by the Department for Culture, Media and Sport.
Map
This map is for quick reference purposes only and may not be to scale. This copy shows the entry on 06-Jun-2026 at 10:30:57.
Download a full scale map (PDF)End of official list entry
All text content is available under the Open Government Licence v3.0 , except where otherwise stated. Any supplied maps are © Crown Copyright [and database rights] 2026 OS AC0000815036 and may not be reproduced without permission.