1872 The sinking of No.1 shaft at Cambrian Colliery in the main Rhondda Valley was begun by S. Thomas and J. Riches and Co.
1874 No. 2 shaft was sunk.
1879 Thomas died. After his death the mines were carried on by Messrs. J. H. Thomas and D. A. Thomas, M.P.
By 1885 the Cambrian Collieries Ltd. had become the new owners and they sunk No. 3 shaft the same year.
1887 Osborne Riches died; control of the colliery passed to Thomas' sons, John Howard and David Alfred, who ran it until 1896
1891 A fourth shaft was sunk
1895 it became the first colliery of the Cambrian Combine.
1895 The company was registered on 4 December, to take over properties from Thomas, Riches and Co. .
1896 The colliery became part of Cambrian Collieries Limited, with a capital of £600,000.
1896 Cambrian Navigation No. 1 and No. 2 pits employed 2,488 men underground jointly, with a further 340 employed on the surface
1905 David Alfred Thomas began to implement his plan to control and regulate the steam coal trade in South Wales and this led to the formation of the Cambrian Combine whose policies led in 1910 to the Tonypandy riots.
1918 David Alfred Thomas died
1929 Cambrian Collieries Ltd. merged with other coalmining companies to form Welsh Associated Collieries
Sources of Information
- The Stock Exchange Year Book 1908
- From the Inspector of Mines' list 1896
- The Times Dec. 30, 1912
-  Welsh Coal Mines