When most people think of the Botallack Mines they inevitably think of the dramatic ruins of the engine houses perched precariously on the edge of the cliffs.
Less well known are the remains of the Lambreth (Cornish dialect for labyrinth) used to separate the tin ore from the containing rock by a process, akin to distillation, known as sublimation.
The ore bearing rock was heated and the fumes lead along a long maze-like flue that at one point crosses over entrance way on an arched bridge before eventually reaching the tall chimney where the waste gases escaped. The impurities contained in the ore would settle out along the flue, and was then scraped off the walls, often by young boys.
Needless to say the whole area is still contaminated with heavy metals (including arsenic), and washing your hands at the earliest opportunity after visiting the site is advisable.
Whilst in this area, don't miss the preserved winding engine at the adjoining Levant Mine, now in the care of the National Trust and in steam frequently through the summer. Check the National Trust site for details.