2.25 tons of charcoal are required to forge 1 ton of bar iron. (18 tons of wood)
2.75 tons of charcoal are required to forge 1 ton of ordnance iron (guns)

Therefore, based on the Dowlais Iron Company 1857 statistic of 118,562 tons of iron being produced, nearly a million tons of timber would have been required for conversion to charcoal.

It should be noted that the Derby's had been using coke at Coalbrookdale for at least fifty years prior to the Dowlais works being opened.

Initially, the amount of coal needed to produce one ton of iron was approximately eight tons, but, with production improvements, this reduced in 1839 to approximately three tons. However, forward planning of coal production was far from evident, thus a great effort resulted in the opening of levels, drifts and balance pits in order to initially maintain and ultimately increase the production of iron.

With the discovery that coke was more efficient than charcoal, coal was used for making the coke. The ironstone was obtained from levels, and leases were granted for men to dig for coal and iron in "patches".

They bored and blasted into the hillsides; water from brook and pond was dammed up to give a head of water which would wash away the loose earth and clay, leaving the heavier ironstone clean and ready for the furnaces. The head of the Rhymney Valley proved to be ideal for the development of iron smelting and, in time, works were established on both banks of the river as far south as Pontlottyn. When they became amalgamated in 1836 they were known as the Rhymney Iron Company.

The South Wales Black Country.

The scars of the coal and iron workings, together with the mounds of iron slag and ash from the furnaces, were still to be seen in the 1970’s, but, as the result of colliery and tip remediation schemes and opencast coal workings, these have now been mostly removed and replaced by grass planted contoured areas between Pontlottyn and Pantywaun, a landscape which formed part of the old South Wales "Black Country", stretching from Aberdare to Abergavenny.