Numerous factories, steelworks, collieries, and potteries were closed, including the renowned Shelton Bar steelworks. The quays were also used to ship coal from local collieries owned by the Priory. The board also took over power stations at some collieries and railway sidings. The Secunda collieries form the world's largest underground coal operations. Telangana is a mineral-rich state, with coal reserves at Singareni Collieries Company. This was a driving force behind the eventual merger with United Anthracite Collieries Limited. The county contained several mill towns and the collieries of the Lancashire Coalfield. Already the riverbanks are showing evidence of past industrialisation, with former collieries and chemical works. Hughes built a steel mill and established several collieries in the region. By 1725 the Newcomen engine was in common use in mining, particularly collieries. Trophy beating Whitby Town and Atherton Collieries. He suggested a tunnel from Hollins Mill, similar to those used for draining collieries. The development was by no means confined to the collieries in the South Wales Valleys. The Oldham Coalfield was the site of over 150 collieries during its recorded history. These included the Hub, Harbour, Caledonia and Glace Bay Collieries.