In 1864 David Davies took a lease of coal in the Upper Rhondda Valley and sank the Parc and Maendy pits. David Davies and Co. was formed as a private company under his chairmanship in 1867 to work these ‘Ocean Merthyr’ pits, and new collieries were sunk — Dare (1868), Western and Eastern (1872), Garw (1884), and Lady Windsor (1885). In 1887 the output had so increased that it was deemed advisable to set up a limited liability company, the Ocean Coal Company Ltd. The inability of the Taff Vale railway and the Bute docks at Cardiff to cope with the Ocean traffic led Davies to promote a new dock at Barry with a railway connection from the Rhondda. The project was carried through after a severe parliamentary fight, and was brought to completion in 1889.

His industrial enterprises made Davies a man of wealth, and he bought various estates and entered public life. In 1865 he unsuccessfully contested Cardiganshire against another Liberal, but in 1874 and again in 1880 he was returned unopposed for Cardigan district. He was returned in 1885 after a contest, but in 1886 he disagreed with Mr. Gladstone over home rule for Ireland and was defeated by nine votes. He was one of the first governors of the University College of Wales at Aberystwyth and in 1875 was elected treasurer, a post which he held till 1887. He was returned unopposed in 1889 to represent Llandinam on the first Montgomeryshire county council.

In 1851 Davies m. Margaret Jones, of Llanfair Caereinion. They had one child, EDWARD (1852-1898). Davies d. 20 July 1890.

Davies was a ‘self-made’ capitalist in an age of expansion. The simple virtues of his youth of penury were unspoilt by the great wealth which he acquired and which he distributed to religious and educational causes and deserving individuals with a generous hand. A Calvinistic Methodist by upbringing, he was imbued with a deep religious sense and was a rigid Puritan in his attitude to drink and Sunday observance. His speech was untutored but with a homely eloquence and a native humour.