The practice of burning limestone to make quicklime has been carried out since Roman times. Most of this quicklime was then ‘slaked’ or mixed with water to make hydrated lime that was the basis of lime wash and lime mortar.
Early production methods were fairly simple. Layers of limestone and fuel were stacked in a mound and then covered with turf and burned slowly, in the same way that charcoal was made.
As demand increased production methods became more sophisticated and the limestone was burned in stone kilns. The kilns on Halkyn Mountain vary in size but the most spectacular is a block of five large commercial kilns at Waen y Brodlas that were designed for high output. Hydraulic lime from here was used to build docks at Liverpool, Birkenhead and Belfast between 1860 and 1890. Lime burning ended on Halkyn around 1914.