The Twrch valley was also heavily industrialised with numerous coal mines and small coal levels along its length as well as two industrial plants for the manufacture of tin plate. In Lower Cwmtwrch the Gurnos works, on the banks of the River Twrch, opened in September 1880 and was closed in 1944 and the Phoenix works on the eastern side of the valley adjacent to the main road through the village opened in October 1879 and closed in the late 1930s.
The Gurnos works site was redeveloped as the Bethel Road Industrial Estate and is also home to Cwm Wanderers A.F.C. (Parc Afon Twrch) whilst the Phoenix site was reclaimed and became the site of the former Ysgol Gymraeg Cwmtwrch. The school has now closed and its pupils transferred to a purpose built Welsh medium primary school for the Ystradgynlais area a few hundred metres away. The new school, Ysgol Gymraeg Dyffryn y Glowyr (The Miners' Vale Welsh School), is built near the site of the former Brynderi coal mine.
There were a number of collieries in the Upper Cwmtwrch area including Brynhenllys (opened in 1872), Henllys Vale (opened in1886) and Brynmorgan (opened in 1807). Little remains of these sites now but the Brecon Beacons National Park Authority has restored a series of lime kilns near the site of Henllys Vale Colliery. Brynhenllys Colliery was powered by the large waterwheel shown in the picture gallery. Other sites down the valley were similarly powered by the River Twrch. There is an excellent pamphlet, prepared by the Town Council, called Ffordd y Glowyr (The Miners' Trail) which describes a pleasant and interesting walk in this area and the pamphlet outlines the area's industrial heritage.
The Welfare Hall in Upper Cwmtwrch, opened in 1924, is the venue for a number of the village's cultural activities. It was erected on a parcel of land leased from Lord Tredegar in 1895 for recreational use in the community. The building was funded from the weekly contributions of the local miners. Ffynnon Cwmtwrch (Cwmtwrch fountain), Lower Cwmtwrch, is a sulphur spring whose medicinal qualities have been greatly appreciated by past generations of the community. The fountain and surrounding land was donated to the public by Colonel Fleming Gough as a 'sign of peace' after World War l.
Maes y Ffynnon was the site of the annual Eisteddfod at Cwmtwrch where a large marquee was erected. The best bard became the recipient of a carved chair. (An example of which – carved Eisteddfod Cwmtwrch 1930 - is displayed at the Parc Howard Museum, Llanelli. This chair was awarded to the winning bard Mr. E. Cadivor Samuel of Llanelly (sic) at the Fourth Annual Eisteddfod held on 14th June 1930 at the Welfare Hall, Upper Cwmtwrch.) It was at Maes y Ffynnon that William Abraham, the charismatic miners' leader of the early twentieth century whose bardic name was Gwilym Mabon, (popularly known as 'Mabon') addressed a large gathering. Mabon brought together the associations of anthracite miners into a single trade union that in 1898 joined the South Wales Miners' Federation (the 'Fed').
The Twrch valley has a number of chapels servingthe various religious denominations. The oldest chapel being Bethania Calvanistic Methodist, Lower Cwmtwrch erected in 1851 with its present building constructed in 1935. The Temperance Hall, in Upper Cwmtwrch was erected in 1860. Originally as a school room it came into being when membersof the nearby Cwmllynfell Independent Congregational Chapel decided a new venue was needed to meet local demand. In 1893 it also became the vestry for the newly-built Ebenezer chapel opposite. It has hosted operettas and even inquests including the deaths of two teenage boys killed in an accident at nearby Hendreforgan Colliery in 1896. It was sold for residential use in early 2012.
Cwmtwrch also has a number of inns which provide wholesome Welsh cooking to a high standard and is the location of the 18 hole Palleg Golf Club and the Brynhenllys Fishery both constructed on reclaimed land following the completion of open cast coalmining in the area.
Upper Cwmtwrch is the home of Cwmtwrch R.F.C. formed in 1890 and whose pitch lies at the foothills of the Black Mountain. The impressive Twrch aqueduct, constructed in 1798, carries the Swansea Canal over the River Twrch in the neighbouring village of Ystalyfera. Hydraulic lime concrete was used in its construction to waterproof the canal bed. This is reputedly the first time the material was used for this constructional purpose. The aqueduct now forms part of Route 43 of the National Cycle Network. South of the villages of Upper and Lower Cwmtwch is the hamlet of Gurnos. The Swansea Canal skirted the village boundary before crossing the impressive Twrch aqueduct . The canal at this point was the terminus of Martin's tramroad, constructed by Edward Martin in 1794 along the Twrch valley from the Bryn Morgan Colliery in Upper Cwmtwrch to convey coal to the Gurnos Wharf for onward transport to the docks at Swansea When the Swansea Vale Railway was extended to Ystalyfera and Brynamman in 1868 Gurnos junction became an important railway hub. It provided a coal marshalling yard for the collieries of the Twrch and upper Tawe valleys, a parcels service for the community and carried the passenger service to Brynamman. The depot closed in April 1962. It is now the location of the small Bethel Road Industrial Estate.
The Gurnos Housing Estate is now the largest estate in the Council's area. Adjacent to the estate is Coronation Park, once an area where iron ore was extracted for the Ynyscedwyn Ironworks but has now been landscaped for community recreation purposes.