David Mushet was born at Dalkeith, near Edinburgh in 1772. His father, although a weaver, established a foundry in Dalkeith and David occasionally went with his to the ironworks. Age 19 he left school and took a job as an accountant at the Clyde iron Works. While there he began experimenting with the iron processes, but later was prevented to do so. He continued he research at various locations in Scotland and eventually was recognised as an expert in the field of iron and steel making.

David Mushet moved to Derbyshire in 1805 and continued to research and published articles on his thoughts and finds. In 1808 he was appoached by Thomas Halford, a wealthy investor fom London, and owner of two furnaces at Whitecliff, just west of Coleford, in the Forest of Dean. Halford asked Mushet for help and offered to pay for his services to improve the quality and quanity of the iron produced.

Mushet recommended a major rebuild of Whitecliff and remained to supervise the work In February 1810 he moved to Coleford and was later joined by his wife and family. He became full-time manager at Whitecliff and invested a quarter share in the business. It seems the major invester, Thomas Halford, began to lose money in other businesses and was bankrupt by 1816.

In 1818 over a period of two years he built a foundry at Darkhill, just south of Milkwall. He continued to produce iron there, but his main interest was in experiementation and research. He became a director of the British Iron Company and, over the next ten years, built a significant empire in iron mines, coal mines, tramways and joined the board of the Severn and Wye Railway and Canal Company. In 1845, at the age of 73, David Mushet retired to Monmouth, leaving Darkhill to his three sons. Robert Mushet, his youngest son, became manager of Darkhill. David Mushet died at Monmouth in 1847 and was buried in Staunton churchyard, in the Forest.

One of Robert's greatest achievements was perfecting the Bessemer process, but his patent expired. Henry Bessemer then claimed to have discovered the same thing independently! In 1857 he produced steel at Darkhill, which was used to produce steel railway lines. They were purchased by the Midland Railway, who were replacing iron rails every 3-5 months. Some of Robert Mushet's steel rails lasted more than 16 years! His second great invention was Mushet's Special Steel. This was tool steel and air-hardening steel and transformed industrial metalworking.

The sad part of the story is that Mushet never really capitalised on his success. While others prospered and made fortunes using Mushet's discoveries he did not. By 1866 he was in ill-health and destitute!

Robert Mushet died at Cheltenham in 1891.

Even though Dark Hill has been partially excavated, the iron works, brick works and partial tramway have survived extremely well! The complex stands on a series of terraces down the hillside. It remains an industrial archaeoloical site of great international importance and is open to the public.