Danygraig Colliery

Crynant, Dulais Valley

The Dan-y-Graig was located at ngr784064 and was worked under license from the NCB in 1959 & early 1970s by the Danygraig Colliery Co (Crynant) Ltd. In 1960 it produced 4,910 tons of coal from the Ynysarwed seam and employed 8 men underground and 2 men at the surface. It was abandoned in 1964.

The No.2 was opened in 1966 working the Ynisarwed seam and employed 14 men. G.I. Thomas was the manager in 1972 when it employed 14 men. From 1975 the owner was J. Horlock who employed J. Morgan as the manager in 1976/78 and O.J. Williams in 1979.

In 1980 the No.2 Slant (c785067) was owned by V.E. Williams and worked the Upper Pinchin seam. The No.2 level was worked by the Three D’s Mining Limited in 1992, while the No.4 level was worked by the same company in the 1994 to 1996 period.

A system called the Trench Method was proposed for this mine, below is the application for that type of mining;

3Ds MINING LTD TRENCH AUGER METHOD STATEMENT OF COAL EXTRACTION.

Executive Summary

The application proposes the extraction of 12,000 tonnes of coal by ‘Trench and Auger’ methods from an approximate 4 hectare area of a Forestry Commission plantation on the Western side of the Dulais Valley.

Mineral extraction would take place over a 6 month period, following which the site will be restored to a combination of deciduous, and conifer forestry and native vegetation. During this extraction period, if required, production from the Dan-Y-Graig drift mine will be reduced by the amount of coal excavated by auger mining so as to comply with the current Dan-Y-Graig mine permission to transport up to 1800 tonnes of coal from the site each week.

Description and Location of Site

The site comprises a 300 metre long strip of land located on the Dulais higher flank of the Mynedd Meurig, an area of highly forested, Forestry Commission woodland situated 1 km north of Crynant in the Dulais valley. The site accesses onto the Treforgan Road and the A4109 is located within the administrative area of Neath and Port Talbot District Council.

There are no groupings of properties near to the site. The nearest residential property, which is in excess of 500 metres from the proposed workings and completely screened from the same is located adjacent to where site accesses on to the Treforgan road to the North West of the auger mining area.

History

The application site has a long history of mining operations. An area occupying part of the current application was worked by underground drift mining and opencast methods from the 1960s to the present time. The site and adjacent areas are also covered by planning permission granted in 2010 for the working of coal by underground methods from Dan-Y-Graig No. 4 drift mine.

These permissions expire in 2020 and provide for the underground mining of high-quality anthracite coal that is contained in an area adjacent to the current proposed auger mining application. The site also includes a small infill mine waste landfill site situated adjacent to Dan-Y-Graig drift mine.

Proposal

The application proposes the phased extraction of 12,000 tonnes of coal over a period of 12 months from a total site area amounting to some 2.38 Hectares. This amounts to 0.18 Hectares for surface development, 0.63 Hectares for storage of overburden and 1.57 Hectares of underground coal seam area. It is proposed to extract the coal by a ‘Trench and Auger’ method where a small surface excavation is made (the Trench) within the existing old opencast cut. A surface Auger is then sited in the Trench and used to extract the coal by conventional surface Auger mining methods. The development involves progressive extraction and restoration, commencing in the South near to the existing Dan-Y-Graig No 4 mine and then working progressively northwest towards the old Dan-Y-Graig Nos. 3 and 2 mines and up to the abandoned Brynant drift mine.

Operations will commence just to the north of the existing Dan-Y-Graig No 4 mine by removing approximately 4 metres of infill material from the old opencast operation in order to create the initial working trench. The loose spoil materials from the previous opencast workings that make up this excavation would be removed and stockpiled along the side of the excavated trench and then reinstated on completion. The Trench would be an average of 5 metres deep 6 metres wide and approximately 300 metres long in order to intercept the coal stratum. The Auger machine will then be sited in the base of the excavation Trench and employed by boring into the coal seam ‘like a giant drill’ up to a maximum distance of 100 metres from the surface to extract coal from the Upper Pinchin seam that had been un-worked by previous mining operations. The coal will be transported from the Auger machine, initially by a chain conveyor delivered onto a belt conveyor prior to loading into a dump truck that will take the coal along a screened haul road to a stockpiling area where it would be loaded into road vehicles.

Access to the surface excavation will be via the haul road already constructed and serving the Dan-Y-Graig No. 4 mine which is currently being reopened. The area required for the development is screened by a densely forested area screening both working operations and the passage of vehicles carrying coal from the surface excavation area to the stockpiling area and down to the main road.

A number of water treatment areas supplemented by cut-off ditches would be used to control runoff from the site and allow for the settlement of solids prior to discharging into existing streams.

Dust created by the Auger machine is not thought to be problematic and any created will be dealt with at the source furthermore any dust created from hauling operations will be contained by water sprinklers as required Debris deposited from transporting the coal will not be a problem as any dirt will be removed from the vehicles before entering onto the public highway. Backfilled areas of the surface excavation would be restored by translocating materials stripped from the area of the advancing excavation supplemented by additional mine materials to bring and restore the area to its original profile. This area will be planted in keeping with the area.

The hours of operation would be restricted to 0700-1800 Mondays to Fridays and 0700-1300 on Saturdays. No vehicles will travel between the hours of 08:30 to 09:30 or 15:00 to 16:00 Monday to Friday to avoid “School Run” traffic. The export of the coal from the site would be via the existing forestry access track which is approximately 1 kilometre long and then onto the Treforgan Road linking with the A4109. Auger mining will generate a maximum of 5 lorry loads of 20 tonne capacity of coal from the site per day. It is estimated that the mining development would generate 4 jobs with a further 3 in associated road haulage.

At the end of the Augering operation the manpower, including haulage positions, will be absorbed into the Dan-Y-Graig No 4 mine.

Other Considerations

Visibility – It is evident from the accompanying sections that the access road is between 4 to 6 metres above the excavated area and any of the auger and coal filling operations are well below the line of sight from neighbouring properties and the main road between Ystradgynlais and Crynant the B4599, the area is also partly screened by trees.

Noise – The diesel generator driving the Auger is an enclosed containerised set with very low decibel levels, machinery used in excavations Volvo loading shovel and Volvo dump truck and 25 tonne excavator are all low noise this coupled with the fact that all operations as explained above take place in the opencast cut and partly screened by trees should greatly reduce the noise which could reach the neighbouring properties, when Auger drilling operations take place a noise survey will be carried out and the results recorded and any remedial action that may be required will be executed.

Water – the coal seam dips away from the opencast cut towards the old underground workings at a gradient of 1 in 12. The Auger will cut through into the underground workings, all surface water will flow via the Augured holes where it will then flow into the existing mine water treatment lagoon that is located within the underground workings of Dan-Y-Graig No. 4 Colliery.

Dust – The cutting operation of the Auger should not generate dust of a quantity to be a nuisance, although during drilling operations this will be monitored and should a problem evolve then systems will be put in place to alleviate any problem, during dry weather periods the traffic on the haul road will be monitored and should a dust problem be encountered due to the movement of lorries both from the Auger operation and lorries from Dan-Y-Graig No. 4 Colliery then a system of towed sprinkler bowsers will be initiated to water down the haul road and suppress the dust. The water used for dust suppression will be sourced from the Dan-Y-Graig No4 site where a 100,000 litre surface water storage system is already in place.

Traffic – The maximum output of coal from both the Auger operation and the output from underground at Dan-Y-Graig No4 Colliery will be limited to a production figure already approved under Danygraig No4 Colliery consent, to alleviate any interaction between lorries accessing the main highway and normal highway traffic, this production figure will give a daily maximum of 18 lorries movements exiting the site.

Information supplied by Ray Lawrence and used here with his permission.