of Aberdare and Rhymney Valleys, South Wales
1835 Thomas Powell, a timber merchant of Newport, established his first colliery
1840 Powell sunk the first deep mine at Cwmbach, Aberdare.
1840-1863 He opened many further deep mines, both in Aberdare (Cwmdare, Abernant, Abergwawr, Middle Duffryn and Cwmpennar) and in the Rhymney Valley. At their peak these collieries produced over 400,000 tons of coal each per annum.
1863 Thomas Powell instructed T. E. Forster, William Armstrong and George Elliot (later to become Sir George) to put a valuation on all his collieries.
1863 Powell died.
1864 George Elliot formed the Powell Duffryn Steam Coal Co Limited (PDSC) for the purpose of working the whole of Thomas Powell's collieries. At this time the wealth of the South Wales Coalfield was only just being realised.
1864 The company was registered on 28 July.
1867 The PDSC bought the Aberaman Estate from the iron master Crawshay Bailey. This included Aberaman Colliery, Aberaman Ironworks, Aberaman Brickworks, the Mansion and all adjoining land. The acquisition of the Aberaman Estate was an important purchase, as underneath lay some of the best steam coal in the world, with easy access to the ports. Aberaman became the headquarters of the company. PDSC coal reached markets worldwide including the railways of India, Argentina, Uruguay and Brazil.
1879 E. M. Hann started work for the company
1896 Owned 11 coal mines
1908 The total mineral area of the properties, situated in the Aberdare and Rhymney Valleys, was about 15,000 acres, of which 1,070 were freehold as regards the surface and two-thirds of the underlying minerals. 
1914 The market in France was so large that they registered as Compagnie Francaise des Mines Powell Duffryn, with their main offices at Rouen.
1916 An able businessman, E. M. Hann (who had started his career in the company in 1879) was made director of the PDSC and enabled the company to become the greatest coal-producing company in the world. Hann acquired all the adjoining collieries (Aberaman, Lletysiencyn, Abernant, Gadlys and Blaengwawr). He succeeded in sinking every one of the company's collieries in the Aberdare Valley to the lowest seam. Hann also saw the erection of the Coal Washery and Electric Generation Station at Middle Duffryn, Aberdare introducing electric power for lighting, haulage, winding, pumping, coal cutting machines etc. Hann's activities also influenced the social welfare and local government of Aberdare.
1920 Acquired the Rhymney Iron Co and its extensive estate; the company also bought thousands of acres in the Llantrisant area.
1927 See Aberconway Chapter 17 for information on the company and its history.
1928 Took over some other Welsh collieries:
and on the distributive side: