Powell Duffryn�s coke ovens and by-product recovery plant at Bargoed were a fine example of colliery enterprise. The company used some innovative methods to fully utilise the by-products of the raised coal. This included washing small coal, coking in re-generative by-products ovens, the manufacture of sulphuric acid and sulphate of ammonia and tar distillation. There was also a benzol plant and an ammonia plant. Some of the coal by-products produced were presotim (a wood preservative), presomet (a black bituminous paint for metals) and syntharar and synthacold (tar products for road services).
In 1934 the company set up a research laboratory to devise new processes for increasing the efficiency of carbonising, distillation and coal cleaning. In 1939 a new tar distillation plant at Caerphilly was opened to distil all the tar produced by the company, and also tar produced by all of the steel companies in South Wales which had coke ovens.
There are many files of correspondence (1917-1951) of Joseph West who was manager of Bargoed Laboratory, then later kept on by the National Coal Board as Carbonisation Officer for No 5 (South Wales) Area. The files include analysis of coal and its by-products, details of coke production and shipments, correspondence specific to certain chemical processes, the ammonia plant, and gasholders and purification. The collection also includes goods outwards books (1925-1951) and would make an excellent resource for historians interested in the ancillary activities of the coal mining industry.