C.F. Casella & Company Ltd. manufactured this thermal precipitator from around 1935. It was used to test coal dust samples taken from the mine.
The increasing use of explosives at the coalface, and the progressive mechanisation of mining during the 20th century, increased the amount of coal dust generated through coal extraction. Although at first it was thought that the increased levels of dust caused no adverse health risk, as the century progressed the need for environmental testing equipment to monitor the levels of dust in the mine became more apparent.
High volumes of coal dust in the mine atmosphere were found to be explosive. Dust was also eventually linked to health complaints suffered by miners including silicosis and miners' asthma.