Sentence:  The Arran coal was used for heating saltpans to produce salt from sea water, and also to fire limestone kilns. Remnants of this industry are still present in the landscape at the Cock of Arran, where mineshafts and the <WSD>panhouse</WSD> (where the iron saltpans were kept) remain, with ruins of the miners' cottages. 
Meaning of the word marked with <WSD> tags:  A building in which seawater is evaporated to make salt.