This is another mine which started
during the tin boom of the early 20th century. However, although it
lasted for longer than many other operations from this period very little
mineral production took place. The mine first
appeared in May 1906 when
North Boscaswell Mine was floated with a capital of £10,000. By September
the mine had a winding engine installed and the new shaft (Trease) was 84
feet deep. The lode was over 2 foot 6 inches wide and assayed 43 lbs of
black tin per ton.
Early the next year the company was
called Boscaswell United Tin & Copper Mines, Ltd and the property
included the setts of North Boscaswell, Pendeen Consols, Trease, Calartha
Farm, Boscaswell Downs, Calartha Common and Portheras. Douglas S. S. Steuart was the managing director
and Pore, Petit and Steuart the
consulting engineers. The day-to-day management was handled by Willie
Thomas who was also managing Botallack; he was the local agent for Steuart.
Back to top^
By 1908 Trease Shaft was sunk 190 feet,
the lode at 180 feet reported as carrying 24.7% copper and 71.2 lbs per ton
black tin. By the end of the year the shaft was down 282 feet and a level
driven 322 feet east. In 1909 Douglas Steuart acquired the surface plant
of Worvas Downs and South Providence mines near St Ives. The equipment included a
20-head Californian stamp battery and some Frue vanners. Later the mill
would include quite exotic
equipment in the form of Pinder tables
(circular rotating shaking tables also called Sturtevant concentrators)
and a Merton roasting furnace. Another shaft, Treweeks, was sunk at some
point. This shaft is located to the north-west of Trease Shaft, close to
the mill.
The mine seems to have spent much time
not working, and there is a gap in the reports from 1910 to 1922 although
it appears to have been working on and off through this period. By 1918
ownership of the property had been transferred to
Home Minerals Ltd, which
also owned Carnelloe Mine near Zennor and Silver Valley near Liskeard. In
the three months to December 1918 the mine had sold 6.3 tons of black tin
worth £1,060. The mine was still being worked in 1919; it is not known
when it closed.
Back to top^
Production:
1911-12: 23.7 tons black tin (Burt et al)
1911-12: 22 tons black tin (Dines)
