Later designers and engineers, such as Thomas Telford, improved both the design and quality of the material in bridges (for example, at Buildwas upstream of Coalbrookdale) and aqueducts (such as the world-famous Pontcysyllte Aqueduct in North Wales).
Charles Bage designed and built the world's first multi-storey cast-iron-framed mill.
Seeing ahead clearly, Darby, sold off his brass business interests and relocated to Coalbrookdale with its plentiful coal mines, water power and nearby ore supplies.
The settlement, located some 5 km from Sasolburg, is a former colliery, and was originally named Coalbrook, probably named after Coalbrookdale in England.
Having had an eye for high-tech from the outset, the LC&N company's founders decided to try some of the railroad solutions put into place in England around Coalbrookdale, which birthed not only railroads, but both the Steam locomotive, and the fixed cable winch enginess which were used in many steep grades as well as for mining hoists.
Albert Edward Bridge, railway bridge spanning the River Severn at Coalbrookdale in Shropshire, England
Taking iron ore from Bo'ness and water from the Carron, they decided to use the new method pioneered by Abraham Darby at Coalbrookdale, using coke from coal mines in the vicinity as fuel rather than the usual charcoal.
Their experimentation using coal in 1766 at the Coalbrookdale iron works under the sponsorship of Richard Reynolds was a precursor to the work of Henry Cort, who further refined their techniques, together with those of Peter Onions, leading to his patent of 1784.
After some commercial failures in the United States, in 1844 the Hardford's family trust sold the works to partners Abraham Darby, Henry Dickenson, Joseph Robinson and J Tothill of Coalbrookdale, with partner Thomas Brown designated managing director.
Rosehill House, forming part of the Ironbridge Gorge World Heritage Site, has been documented in Emyr Thomas's book Coalbrookdale and the Darbys.
His father managed the works at Coalbrookdale from 1763 to 1768, following the death of Abraham Darby II and the coming of age of his son, Abraham Darby III.