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Summary

Trease was a centre of operations of Boscaswell United during the 1907 workings.

Protected Status: None recorded

Other References/Statuses

• Cornwall PROJECT ID: WH
• Primary Record No. (1985-2009): 162189
• SHINE Candidate (Yes)

Monument Type(s):

• MINE (Post Medieval - 1540 AD to 1900 AD)

Full description

Trease was a centre of operations of Boscaswell United (42731) during the 1907 workings. The shaft was re-opened and a group of buildings constructed around it. Little development work was done underground before the company went into liquidation.
Site surveyed by Sharpe in 1992 (b1). The principal shaft worked was at SW 3802 3502. This sits at the centre of a large, partly-revetted mound of spoil. A timber cover (presumably installed by Geevor) secures the shaft, which was collared in concrete. Fuel ash in the dump suggests that there was a small steam engine somewhere nearby. To the rear of the shaft dump, a raised stone-revetted tramway leads away to the south. This can be picked up where it crosses the footpath, where the wheel ruts for a narrow gauge tramway are visible. To the south of this, the tramway survives as a narrow holloway, but the remainder of its route across the fields to Treweek's Shaft (shown by the Ordnance Survey in 1908) has been grubbed up. There was a second tramway or cart road just to the east (possibly an earlier system connecting production shafts to the dressing floors) which can be traced as a hard-surfaced roadway from SW 3807 3501 back to SW 3825 3477.
To the south of the shaft were three rectangular stone buildings with concrete floors (SW 3806 3500, SW 3803 3498, SW 3802 3497), now partly demolished which must have been the service buildings for the mine. Their precise functions could not be identified, but are likely to be documented in detail (the Geevor archive may house this information). To the east of the shaft (SW 3803 3503) are the possible foundations of a rectangular building, perhaps the power source for winding and pumping. To the south-west of the shaft (SW 3800 3500) are the remains of a concrete-constructed building, possibly the site of the ore bin.
The remainder of the dressing floors lay downslope, and were centred at SW 3802 3511. At the head of the terraced, concrete-constructed floors can be seen machine bases and ore chutes where primary crushing took place. The remainder of the mill area is heavily overgrown with gorse, and features are difficult to pick out, but there appear to have been a series of terraced areas where shaking tables, buddles, etc. were sited. Gorse clearance followed by survey together with documentary research would greatly clarify the layout of the site. The sites of two large rectangular reservoirs flank the mill site at SW 3800 3507 and SW 3807 3511.
A little way to the north-west (at SW 3800 3515) are the arsenic calciner and associated tin floors. The calciner is of an unusual design, though seems to incorporate castings from a standard pattern Brunton calciner. Although parts of the structure have been demolished, some of the ironwork survives. The calciner hearth appears to have fed gases into two arch-headed condensing chambers (rather than a conventional labyrinth), connected to a short stone-built stack. To the north-east, enclosed within a concrete structure is a single conical-centred concrete buddle, whilst at the end of the building, the floor is marked by circular impressions which suggest that kieves were sited here. Further rectangular tanks and an additional buddle were sited downslope from the calciner, whilst downslope again was a small stone-faced loading dock. The function of a small overgrown square-plan building at the end of the loading dock (at SW 3802 3518) is unknown.
Although the shaft at SW 3802 3502 was that used in the last working of the mine, other shafts lie in the surrounding landscape. A line of prospecting pits extend from SW 3804 3500 back to SW 3808 3496. Additional shaft or lode-back pit sites are at SW 3800 3505, SW 3799 3804, SW 3798 3505 (Trease Shaft), SW 3798 3506, SW 3797 3507 (possible site), SW 3796 3507. There is what might have been a flat rod trench from SW 3796 3507 to SW 3794 3510, apparently heading for a shaft at SW 3788 3517. At SW 3794 3526 is an elongated spoil dump that may have been associated with a shaft, whilst another shaft was probably at SW 3778 3512, where a large dump of spoil stands at a field junction.

Historic Environment Projects, 2014, Trease, Pendeen, Cornwall (Report). SCO27180.

Cornwall Archaeological Unit, 2016, Trease, Pendeen, Cornwall (Report). SCO27427.

<1> Sharpe, A, 1992, St Just, an Archaeological Survey of the Mining District Vol 2, 36-38 (Bibliographic reference). SCO4373.

Sources / Further Reading

Associated Finds: none recorded

Associated Events

• ECO1489 - Cornish Mining World Heritage Site Bid
• ECO1781 - CM World Heritage Bid: Devon Great Consols
• ECO2465 - Cornish Mining World Heritage Site Bid
• ECO2466 - Cornish Mining World Heritage Site
• ECO4347 - Trease, Pendeen, Cornwall (Ref: 2014R041)
• ECO4587 - Trease, Pendeen, Cornwall (Ref: 2016R005)

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