Harraton Colliery. This was served by a Tramway and Harraton Wagonway, (HER 3023 and HER 3036 respectively). A colliery at Harraton may have been amongst the first in Washington to operate, with a shaft possibly being sunk as early as around 1590 {Durham County Record Office NCB 24/117}.

In 1603 a London merchant, Robert Bromley, leased Harraton Colliery for £300 per annum and that year it had 6,000 chaldrons of coal available. In 1605 Sir John Bourchier leased the colliery for £500 per annum on behalf of a group of London businessmen. By the 1630s it was producing 6,000 tons of coal (10,000 were shipped annually from Wearside). An account of 1635 says Harraton Colliery had 'divers ingines, trammes, shouells'. John Shepardson and his family then ran the colliery, followed by a consortium led by Robert Conyers. In 1644 the colliery was leased to Sir William Wray of Beamish. In 1647 George Grey of Southwick and George Lilburne of Sunderland became lessees. In 1649 with the establishment of the Commonwealth, Sir Arthur Hazelrigg, Governor of Newcastle, seized Harraton Colliery on behalf of the state, and it was leased to three officers in his army. After the Civil War, Harraton estate was divided into three. Two parts were held by Colonel John Jackson and one by the dower of Dame Dorothy Hedworth (widow of John Hedworth). She married Colonel Jackson in 1655. In 1696 Dorothy Hedworth married Ralph Lambton.

On 11th Jun 1794 there was an explosion, 28 lives were lost. Another explosion on 29th Nov 1808 killed more than 4 people. An explosion on 30th Jun 1817 at Row Pit killed 38 people. On 2nd Jul 1817 choke damp killed 8 people. By the 1820s there were three pits - Big Pit, Billy Pit and Row Pit (HER 3024). The colliery was being operated by Messrs Lamb & Co. In the 1850s it was run by Stobbart, Bell & Co. The landowner of the Harraton Estate, the 2nd Earl of Durham, died in 1879 and his estate passed to Lord Lambton. By 1896 the Lambton Colleries LTD owned Harraton Colliery. In that year 688 people worked at the mine. They became part of the lambton and Hetton Collieries Ltd in 1911.

In 1924 it became part of the Lambton, Hetton and Joicey Collieries Ltd, the largest colliery company in County Durham, owning 22 collieries. In 1947 the National Coal Board took over. The colliery closed on 29 May 1965, employing 762 people. For many years Harraton Colliery was known as 'Cotia Pit'. This was because of the large number of Scottish people working there, who had migrated south for work.

The name 'Cotia Pit' comes from Nova Scotia, which the area became known as to the local people.