the twin shafts in 1911 reached the coal seam at a depth of more than 850 yards in 1915, placing them 2000 ft below sea level and making Nantgarw the deepest pit to be sunk in the South Wales Coalfield up to that time. Having suffered from various geographical issues, Powell Duffryn designed a development scheme in 1937, but work was suspended when World War II broke out in 1939. A later project to re-open the colliery was approved by the Ministry of Fuel and Power in 1946, and after nationalisation in 1947, the National Coal Board invested £5 million on modern surface constructions and modern mining methods. Having survived the mass pit closures of the 1960s, the geographical problems meant the closure of the mine working in 1974, and the unit merged with Windsor Colliery, Abertridwr, Caerphilly from 1975. By 1979, the combined Nantgarw/Windsor Colliery employed around 650 men, producing over 4,000 tons of coal per week, making a profit of over £0.5 million. The unit lost £7 million in 1981, employing: 142 on development; 131 on the coalface; 197 below the ground; 101 on the surface. In 1982 output declined steeply as a major coal seam at Windsor became unworkable, while in 1984 an overtime ban led directly to the 1984/5 UK miners strike spreading to South Wales. Although profitable post the strike, both sites of the whole unit closed as part of the NCB regional review on 6 November 1986. Village today The village declined after the 1969 construction of the A470, which destroyed most of the historic old village. The only original buildings that remain are Nantgarw Pottery and a handful of houses in close proximity. After the closure of the Nantgarw/Windsor Colliery and Coking works 18 months after the miners' strike, the site was developed as Parc Nantgarw, joined to the larger Trefforest Industrial Estate. All that now remains of Nantgarw colliery are two small concrete pyramids marking the sites of the two shafts and a commemorative winding wheel. Parc Nantgarw is home to the headquarters of Cadw (the Welsh equivalent of English Heritage), and a large office for the newly relocated Santia Consulting. The social side of the estate provides a cinema, indoor 10 pin bowling and various restaurants. GE Aviation Wales, located on the Caerphilly Road, employs about 1500 people in the testing, repair and maintenance of aircraft engines, including GE90, GP7200, CFM56