Lewis was born in 1837 in Merthyr Tydfil, Glamorganshire, the second son of Thomas William Lewis, an engineer at the Plymouth, and his wife Mary Anne. He was educated at a local school run by Taliesin Williams until the age of thirteen when he was apprenticed to his father as an engineer. In 1855 Lewis was appointed as an assistant to W. S. Clark, the chief mining engineer of John Crichton-Stuart, 3rd Marquess of Bute. He spent ten years in that post before succeeding Clark in 1864. Lewis was given the occupancy of Mardy House as part of his job, which became his long-term residence in Aberdare. The same year he married Anne Rees, daughter of William Rees, and granddaughter of Lucy Thomas, the legendary "mother of the Welsh steam-coal trade". Lewis and Anne had two sons and six daughters. He at first worked for the Bute coal mining pits in southern Wales, but between 1870 and 1880 he acquired his own pits in Rhondda, which became known as Lewis Merthyr Consolidated Collieries Limited. He was also the founder of the Monmouthshire and South Wales Coal Association as a response the growing strength of the trade unions.
Public life
Lewis commenced his career in public life in 1866, when he was elected to the Aberdare Local Board of Health. In 1889 he was stood for election to the Glamorgan County Council for the Hirwaun ward. The contest was marked by accusations that Lewis, as a prominent coal owner and land agent, had refused requests by nonconformists for land to build chapels. He publicly refuted these allegations, at a meeting held at Ebenezer, Trecynon. Lewis's supporters also counterred these claims by publishing old correspondence, including a letter by the late Thomas Price which refuted the accusations. There is evidence that Lewis's personal popularity transcended any political considerations. Lewis defeated the Liberal candidate, a local Methodist minister, Richard Morgan, and was immediately made an alderman. At the end of his six-year term he did not seek re-election.
One of the pits owned by Lewis was the Senghenydd Colliery. Following a failure to implement a safety plan in early 1913, an explosion in the mine on 14 October of that year killed 439 miners and one rescuer. This remains the worstmining accident in the United Kingdom. Lord Merthyr, together with the colliery manager, was subsequently fined a total of £24.
