The 13.5km section of M4 motorway between Llangyfelach (junction 46) and Pont Abraham Services (Junction 49) is known as the Pontarddulais bypass.
It was designed by a local firm, W S Atkins & Partners (who have kindly supplied the project with copies of the original plans) and was built by Sir Alfred McAlpine & Son Ltd at an estimated cost of £15.4 million. The stretch of motorway was opened on 29th April 19977.
The project was made difficult due to “unworked coal which was encountered unexpectedly in the largest cutting on the job at Penderi, which was excavated and taken to Morlais colliery for washing and subsequent sale. This operation slowed down the completion of this cut at a time when the fill was urgently needed to complete the embankment to the west.” (145) This was the section of the Motorway just below Llys Nini, and under the roundabout at Junction 47.
The plans left show the M4 engineers' drawings of the coal under the proposed path of the motorway.
The archive suggest that the Engineers knew about the mine workings at Llys Nini as it states “Old workings west of Penderi at Llysnini, indicated in the contract to be grouted, were also excavated and backfilled.” (145) However, Sion Alun, who was resident at Llys Nini at the time recalls that the extent of the workings were a surprise to the contractors. “When the people came to do the survey for the M4, my father warned them about the mines but they said that they had all the old surveys and there was no record of any mine workings. But the mines must have been older than the NCB and were not recorded.
“Before starting to build the motorway they had to move the electricity pylons. I remember they drove their bull dozer on to site, into the wood and through the trees – I remember it as it was so upsetting. They drove the bull dozer into the trees and it went straight down.
“When they realised what was happening they brought in specialists. They dug around the hole and opened it up. It was fascinating; to think that human beings could work in those conditions, some of the tunnels were no more than 3’ high. Some of the tunnels went over to Bachygwreiddyn Farm. They spent a long time filling in the runs underneath the motorway.”
Plans of the motorway section show the mine workings under the proposed carriageway. Perhaps the planners had not surveyed to the side of the motorway line, which caused the contractors moving the pylons problems. If the mine was charted it is possibly the St Dewi Colliery.
Frazer Gardiner (141), an engineer working on the site, told the project that he was involved in preparing for the work at Llys Nini. They knew that there was nothing of archaeological interest at the site but that they would have realign the pylons, reroute Llys Nini’s access road, possibly realign a water main and build some banking at the Penderi Cut.
He said that they opened up the mine at Llys Nini, he thought that it had closed sometime between 1910 and 12. It was a drift mine probably mining the Swansea 3’ seem. The pit props were still in place and the majority of the workings were in pristine condition. However, it looked like part of the mine had later been re-opened and mined without props and due care to safety. He wondered if this had happened in 1926, during the General Strike. Local “owned” mines would have been closed and the miners locked out, so possibly some enterprising locals, knowing of the seam, had opened it up in order to make some money.
Hugh Jones (142), another engineer on the project, believes the mine was the St David’s. “It was 6m deep and ran between sections 11300 to 11600”
The plans for the bank at Penderi clearly show the presence of coal.
The engineers built their first site office close to Llys Nini just off the A48. Unfortunately they could get a telephone line to the site and so couldn’t use it.
Frazer remembers that in the early days he lived in a caravan at Llys Nini.
Hugh Jones, now living in Pontlliw, was employed in the early stages of the construction. As a Welsh speaker, he had to liaise with local land owners, tenants and farmers whose land would be affected by the motorway construction.
He recalled how the people in Melin Llan Cottage could hear the coal drams in the Tir Donkin Colliery hundreds of feet below them. Mrs Fawcett-Gandy, who owned the house, fought the construction of the motorway, which originally wanted to demolish the bridge which gave access to the cottage. She had a preservation order put on the building and the contractors had to almost completely reconstruct the 300 year old bridge over the River Llan to the cottage.
The contractors based a number of their vehicles near Penderi Fawr Farm, This was where the roundabout for Junction 47 was to be built.
He remembers the farmer at Penderi Fawr having issues about the contractors damaging his land so he locked his gates trapping the construction vehicles until it was resolved.
When they were drilling for the foundations of the Penderi Bridge, they were expecting about 6m of rock and then river gravel but they encountered much more coal than expected. It all had to be dug out and given to the Coal Board. It was taken to the Brynlliw Mine where it was washed and then sold.
They had another surprise when they drilled just inside Llys Nini’s present gates. They hit gas, at first they thought it was methane from a disused mine, being brought to the surface by convection currents, but they soon found it was “town gas” as they had hit a gas main.
Ty’r Heol Cottage marked on map
Two houses had to be destroyed to make way for the road. Ty’r Heol which was just south of Penderi Cottages and the 400 year old Tal Y Clun at Hendy.
The actual construction was done by navies from the Stockport area, he didn’t remember any problems with them not them having problems in a predominantly Welsh speaking area.
M4 Construction – Memories of Frazer Gardiner and Hugh Jones