The Lambton Colliery consisted of seven pits with coal transported on horse-drawn wagonways to staithes on the River Wear. From the early 19th Century transport was by rail directly to Sunderland. Many of the ships taking coal to Europe would return laden with silica sand and red Flemish bricks. Sand supplied the bourgeoning glass industry in Sunderland and the bricks were used at Lambton Park, including it is believed, in their millions, as rubble to stabilise the mines beneath the Castle.
The first Earl had a genuine concern with the difficult life of the coal miners. He established and largely financed the Lambton Collieries Association, providing accident insurance and a rudimentary pension scheme for his miners. The Earl also corresponded with Humphry Davy, who in 1816 produced the Davy lamp, which saved many lives, detecting poisonous and flammable gases. It is believed that Davy trialled the lamp at one of the Lambton pits.
The Lambton Colliery Company went steam powered from 1814 and by 1860, the Lambton Railway was the largest of all the colliery railways in the north east, with over 70 miles of track.
In 1947, all private coal companies in the UK were nationalised. Lambton Colliery closed on the 27th February 1965 and across the region disused colliery structures were removed and spoil heaps landscaped, leaving very little evidence today of this once-dominant industry. There is however, still evidence in the Park, as it is possible to see parts of the wagonways and unusually the banks of the River Wear, in front of Lambton Castle, were hard-lined to enable ‘keel boats’ at the time to ferry the coal down to the deeper water and the larger waiting ships at Sunderland.