Tondu (Welsh for black sward) is a small town near Bridgend in south Wales.
Tondu lies on the A4063 from Bridgend to Maesteg, and was established in the late 18th century as a mining village servicing the Parc Slip colliery. In later years, an iron works was also established, and in the 19th century, a brick works was constructed using the clay from the Carboniferous coal measures to make a variety of bricks, mostly for engineering. The brick works was eventually demolished in 1977. The association with the coal industry was also reflected in the large area office of the National Coal Board in the town and a centre for the Mines Rescue Service. Parc Slip colliery was opened by the Llynfi, Tondu and Ogmore Coal and Iron company, which in 1899 became North's Navigation Colliery Company Ltd. On the day of the annual St. Mary Hill Fair, August 26, 1892, a huge explosion shook the mine; 112 men and boys died with just 39 survivors, some remained trapped underground for a week before being rescued. Sixty women were widowed and 153 children left fatherless. The mine closed in 1904. A memorial to the disaster still stands consisting of 112 stones - one for every death. Much later, the coal seams were re-worked as part of the Parc Slip opencast coal mine.
The town has several railway lines and provided access to collieries in Wern-Tarw and the Ogmore and Garw valleys, along with maintenance facilities. All were closed to passenger traffic in the 1960s. They were used extensively by coal trains until the mine closures in the 1980's. The Wern-Tarw line was disused and lifted first, followed by the Ogmore line sometime afterwards. The Garw line is disused, but still extant. During the early 90's the Bridgend to Maesteg line was re-opened to passenger traffic and provides a service from Maesteg to Bridgend and Cardiff. Occasional steel trains can be seen using Tondu as an alternative route via the Margam to Tondu and Tondu to Bridgend branch lines. The Margam line is now used by the new Parc Slip opencast mine for coal traffic.
The River Llynfi flows alongside Tondu on its way to its confluence with the River Ogmore. The Llynfi at this point has had a history of severe pollution. Historically, the pollution started with the coal industry. The coal seams in this part of the south Wales valleys are quite wet and the coal itself is rich in pyrites and thus also rich in sulphur. Such mine waters have a very high burden of coal and rock solids and also contain heavy metals such as nickel, iron and copper in acidic solution. In the 20th century, with the introduction of coal washeries, the mine waters became very rich in fine rock solids. The river also takes away the sewage from Maesteg, originally as crude sewage and then later as treated sewage in a treatment plant that was severely overloaded for much of its life. The establishment of a large paper mill and a cosmetics factory in the 20th century only added to the pollution load. As a result, the people of Tondu became inured to a river in their presence which was visibly very polluted and even changed colour as different types of paper were manufactured at the paper mill, and which also smelled strangely: a mixture of perfumes from the cosmetics factory and sewage from Maesteg.
Tondu is now rapidly becoming a dormitory suburb of Bridgend. It has lost its primary school and its identity as a separate small town is eroding away.