Partial remains of the earliest known Hoffman type limekiln. The design, which was patented in Germany by Friedrich Hoffman, enabled the process of lime production to be continuous, with a burning zone progressing around a circular or oval tunnel to areas newly packed with stone. The kiln at Minera, which was built in 1868, is some 80m long with a continuous tunnel accessible through 24 entrance archways. A smoke chamber survives at the top level at the south end and stoke holes and flues are apparent throughout.
Source: Cadw scheduling description..