Rock Valley Works was located in the River Maun Valley at Mansfield, Nottinghamshire.
The first known industrial use of the site is in 1835 by a water powered mill, known as Rock Mill, located on the river and it was used for the production of mustard. The site expanded with more industrial units including a colour mill, a tannery and wood-turning and saw mills. Mustard production was the principal commodity at the works and Rock Mill expanded utilising a steam powered process designed by the Barringer and Brown Company which included the manufacture of tin containers. The demand for tin containers became so great that after a major fire in 1873 the rebuilding of the factory saw production shift to tin ware.
The tin ware and mustard production expanded and took over the site at Rock Valley so by 1895 that a separate company, Barringer, Wallis and Manners, was established in the former bleach works south of the site. The site divided into two separate sections, with 'Rock Valley Mill' at the north end producing mustard and 'Rock Valley Tin Works' to the south. Over the next thirty years, the bleach works site was intensively developed with four new three storey blocks being built. In 1919, a further phase of development began with the construction of the four-storey Tower Block, designed by Mansfield architects, Cook, Howard and Lane. The building, with its prominent landmark clock tower, was completed in 1927, and provided spacious production floors and a machine-tool room, which considerably enhanced the company's production capacity.
The mustard business was sold to Coleman's of Norwich in 1919, and in 1939 Barringer Wallis and Manners was incorporated into the Metal Box Company. It now forms part of Crown Specialty Packing. The west wing of the original mustard mill complex was demolished in 1953. The Rock Valley Mill site was recently sold to Walkers Transport of Mansfield.
No part of the site was deemed worthy of a listed status. It was demolished in 2011 leaving the clock tower standing. The clock tower was severely damaged by metal thieves who stole many of the copper tiles from the domed roof.