This smelt mill is set just a few yards below Marrick High Lead Smelt Mill. Originally the two mills where distinctly separate, but in 1862 found that the High Mill was beyond use and concentrated improvements on the Low Mill. It was at this time the twin flues were extending up to the High Mill chimney. This allowed them to reclaim some of the 'fume' or 'lead soot'. A new waterwheel was also installed together with a new launder for the wheel.