In 1734 Carlisle Spedding built two salt-boiling pan houses at Saltom Pit.

One of the colliery Newcomen engines pumped seawater into the pans. Salt pans were normally 22 Feet long 12 foot wide and 6 inches deep. The pans were made from thick iron plate or lead and were operated by four women and one man. Coal from the pit was burned to boil the seawater.   The pans could produce 2 gallons (9.1 litres) of salt in 4 hours.

Dr William Brownrigg used the opportunity to examined the salt-boiling process.  He and Spedding would have worked together to find the best methods.  Their work made money for Saltom (salt was as profitable as coal and lighter to carry!), and it made Saltom famous.

In 1755 Angerstein an industrial spy from Sweden visited Saltom to find the secret of their success.  His notes describe a 'substantial masonry sump' on the foreshore at Saltom.

The salt pans were closed in 1780.  One of the pan houses was converted into a foundry making furnace bars and cast iron goods for the colliery.