Proposed Taf Ely Learning Campus Coleg Morgannwg, Glamorgan

Mine Working Risk Assessment

Nantgarw Colliery under construction June 1951

Nantgarw in 1974

Seam Approx. Thickness (m) Approx. Depth to (m)

Dirty Coal 1.30 25.4

Brithdir Rider 0.30 93.50

No. 1 Rhondda 1.00 445.0

No. 2 Rhondda 0.30 475.0

No. 3 Rhondda 1.00 570.0

Lower Pentre Seam 0.65 640

Gorllwyn Rider Seam 0.30 650

2 Foot 9 inch Seam 0.65 690

4 Foot Seam 1.20 700

6 Foot Seam 1.80 715

Upper 9 Foot Seam 1.50 735

Lower 9 Foot Seam 1.0 765

Bute Coal Seam 2.40 780

Yard / 7 Foot Seam 2.60 825

Standard 5 Foot or Gellideg Seam 1.50 860

Table 5-2 Conjectured Stratigraphical Success beneath the Site - Bedrock Source: BGS Geology of the Country around Newport. Memoirs for Sheet No. 249 Note. The Yard or 7 Foot Seam and the Standard 5 Foot / Gellideg Seams were not recorded within the geological sequence for the South Shaft at Nantgarw Colliery detailed within the Geological Memoirs and so their depths have been extrapolated from the stratigraphical column from the published geological sheet No. 249

The generalised stratigraphical section indicates those mineral seams for which it is known or which it is reasonable to assume mining has taken place to some extent beneath the site.

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6 Mine Workings 6.1 Coal Mining Report

A coal mining report was obtained for the site from the Coal Authority and is included within Appendix C. Details on the findings from the report and discussed in the following sections. 6.1.1 Underground Coal Mine Workings

The property is in the likely zone of influence from workings from 5 coal seams at depths ranging between 570 and 970 metres with the last seam worked in 1962.

Ground movements associated from these coal mine workings should have stopped.

The Coal Authority believes that there is coal at, or close to, the rockhead level below the site that may have been worked at some time in the past, although, from a review of the abandonment coal mine plans for the site there is no evidence to substantiate the presence of shallow mine working beneath the site.

The site is not within a zone of influence from current operational underground coal workings and also the site is not within an area for which the Coal Authority is determining whether to grant a licence or whether a license has been granted to remove coal using underground methods.

The property is not in an area that is likely to be affected at the surface from any planned future workings. However, coal reserves exist in the local area which could be worked at some time in the future.

No notice of the risk of the land being affected by subsidence has been given under the Section 46 of the Coal Mining Subsidence Act 1991. 6.1.2 Mine Entries

There are no known coal mine entries within or within 20 metres of the boundary to the site. However, it should be noted that it only became legislation in 1872 with the Coal Mines Regulation Act that abandonment mine plans were to be undertaken, and so many shallow workings would have been abandoned prior to this time and so it is possible that unrecorded shallow mine entries and workings may be present at the site. 6.1.3 Opencast Coal Mining

The site is not within the boundary of a former opencast site or within 200 metres of an operational opencast coal mine.

The site is not within 800 metres of the boundary of an opencast site for which the Coal Authority is determining whether to grant a licence or whether a licence has been granted to remove coal by opencast methods. 6.1.4 Coal Mining Subsidence

The Coal Authority has not received a damage notice or claim for the site since 1 January 1984, which is based on when the first standard mining report enquiry form was introduced in 1989,

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which asked whether any claims had been made or pursued ‘in the lat five years’ i.e. since 1984 and so all subsequent editions of the standard enquiry form have retained this 1984 start date.

There is no current Stop Notice delaying the start of remedial works or repairs to the property. The Coal Authority is not aware of any request having been made to carry out preventive works before coal is worked under Section 33 of the Coal Mining Subsidence Act 1991. 6.2 Mine Workings – Envirocheck Report

An Envirocheck Report included within the Interpretative Report on the Site Investigation, Report No. J9045 dated December 2009 prepared by Soil Mechanics noted the following:

The site is within an area affected by coal mining activity and that the site is approximately 140 metres from a recorded BGS mineral site, Nantgarw Mine that extracted coal by underground working methods which has ceased operations.

The report considers that there is no hazard associated with the potential for collapsible ground stability, whilst there is a moderate risk associated with the potential for compressible ground stability hazards.

There is no hazard associated with the potential for ground dissolution stability, whilst the risk associated from shallow mining is considered to be low to moderate. 6.3 Coal Mine Abandonment Plans

A review of the Coal Mine Abandonment Records for the site held at the Mine Records office of the Coal Authority based in Mansfield, Nottinghamshire was undertaken with the plans reviewed for the site detailed within Section 3, with extracts from the plans included within Appendix D 6.3.1 Mine Entries

The ‘North’ and ‘South’ Shafts associated with the former Nantgarw Colliery are located approximately 150 metres to the east of the site boundary to the proposed Taf Ely Learning Campus with the location of these shafts shown on Drawing Nos. 0004-NE02987 to 0010- NE02987, in Appendix D.

These shafts were completed in 1910 and reached depths of 760 metres and 785 metres for the ‘North’ and ‘South’ shafts, respectively.

Record SWA3224 Sheet: Shaft Infilling Scheme – Nantgarw Colliery obtained from the Coal Authority indicates that these shafts were infilled with stone, with the infilling works completed in January 1987.

The risk associated with these shafts is considered to be low as these mine entries have been infilled and are shown to be outside the site boundary, however, it is recommended that these mine entries are located and identified to confirm their location in relation of the proposed works. 6.3.2 Underground Coal Mine Workings

The coal mine abandonment plans relevant to the site refer to the historical underground mine workings from the Nantgarw and Windsor Colliery.

A summary of the historic underground workings beneath the site is provided within Table 6-3.

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PLAN COLLIERY SEAM DATE APPROX. TYPE OF EXTENT OF WORKINGS AT SITE PRELIMINARY RISK ASSESSMENT REFERENCE ABANDONED DEPTH TO WORKINGS WORKINGS BASED ON ‘SOUTH SHAFT’ STRATIGRAPHI CAL RECORD

(METRES)

Risk: Low. Roadways and galleries from Nantgarw North and Due to the depth of the workings; it is considered that South Shafts within 20 metres of the eastern site the risk from mining subsidence is low based on the boundary. Main workings are outside footprint of site to SWA1016 Nantgarw Colliery No. 8 Seam April 1959 530 Long wall guidance provided within CIRIC SP32. the east and south.

Refer to Drg No. 0004-NE02987, Appendix D.

Risk: Low.

Due to the depth of the workings; it is considered that 2 Foot 9 inch Roadways and galleries from Nantgarw North and 9274 Sheet 3 of 4 Taff Rhondda the risk from mining subsidence is low based on the Seam Pillar and South Shafts extent below the eastern area of the site. dated October Navigation Colliery - October 1927 690 guidance provided within CIRIC SP32. Stall Main workings are outside footprint of site to the east. 1927 Nantgarw

Refer to Drg No. 0005-NE02987, Appendix D.

9274 Sheet 2 of 4 Taff Rhondda Risk: Low. Pillar and Workings below footprint of proposed development. dated October Navigation Colliery - October 1927 Stall Due to the depth of the workings; it is considered that 1927 Nantgarw Refer to Drg No. 0012-NE02987, Appendix D. the risk from mining subsidence is low based on the 4 Foot Seam Roadways and galleries from Nantgarw North and guidance provided within CIRIC SP32. 700 (No.18) South Shafts within 20 metres of the eastern site SWA1016 dated boundary. Main workings are outside footprint of site to Nantgarw Colliery January 1954 Long wall November 1954 the east and south.

Refer to Drg No. 0006-NE02987, Appendix D.

Roadways and galleries from Nantgarw North and Risk: Low. South Shafts within 20 metres of the eastern site 9274 Sheet 1 of 4 Taff Rhondda Pillar and boundary. Main workings are outside footprint of site to Due to the depth of the workings; it is considered that dated October Navigation Colliery - October 1927 Stall the north and east. the risk from mining subsidence is low based on the 1927 Nantgarw guidance provided within CIRIC SP32. 6 Foot Seam 715 Refer to Drg No. 0013-NE02987, Appendix D. (No. 22)

SWA1131 dated Nantgarw Colliery January 1973 Long wall Sept 1956 Workings below footprint of the site.

January 1987 Long wall Workings below footprint of the site. SWA3224 dated Nantgarw / Windsor

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PLAN COLLIERY SEAM DATE APPROX. TYPE OF EXTENT OF WORKINGS AT SITE PRELIMINARY RISK ASSESSMENT REFERENCE ABANDONED DEPTH TO WORKINGS WORKINGS BASED ON ‘SOUTH SHAFT’ STRATIGRAPHI CAL RECORD

(METRES)

1981 Colliery Refer to Drg No. 0007-NE02987, Appendix D.

Roadways and galleries from Nantgarw North and Risk: Low. 9274 Sheet 4 of 4 Taff Rhondda South Shafts extent below the eastern area of the site. Pillar and dated October Navigation Colliery - October 1927 Main workings are outside footprint of site to the north. Due to the depth of the workings; it is considered that Stall 1927 Nantgarw the risk from mining subsidence is low based on the Refer to Drg No. 0011-NE02987, Appendix D. guidance provided within CIRIC SP32.

Roadways and galleries from Nantgarw North and SWA3215 dated South Shafts within 20 metres of the eastern site Nantgarw Colliery November 1956 Long wall Nov 1956 Upper 9 Foot boundary. Main workings are outside footprint of site to 735 Seam (No. 24) the north and east.

Roadways and galleries from Nantgarw North and South Shafts within 20 metres of the eastern site boundary. Main workings are outside footprint of site to SWA3224 dated Nantgarw / Windsor January 1987 Long wall the north and east 1986 Colliery Refer to Drg No. 0008-NE02987, Appendix D.

Roadways and galleries from Nantgarw North and Risk: Low. South Shafts within 100 metres of the eastern site SWA3224 dated Nantgarw / Windsor Yard / 7 Foot boundary. Main workings are outside footprint of site to Due to the depth of the workings; it is considered that January 1987 825 Long wall 1986 Colliery Seam the east the risk from mining subsidence is low based on the guidance provided within CIRIC SP32. Refer to Drg No. 0009-NE02987, Appendix D.

Roadways and galleries from Nantgarw North and Risk: Low. Standard 5 South Shafts within 20 metres of the eastern site Foot / Gellideg SWA1250 dated boundary. Main workings are outside footprint of site to Due to the depth of the workings; it is considered that Nantgarw Colliery Seam February 1976 860 Long wall January 1976 the east the risk from mining subsidence is low based on the guidance provided within CIRIC SP32. (No.28 Seam) Refer to Drg No. 0010-NE02987, Appendix D.

Table 6-3 Coal Mine Abandonment Plans Note. The Yard or 7 Foot Seam and the Standard 5 Foot / Gellideg Seams were not recorded within the geological sequence for the South Shaft at Nantgarw Colliery detailed within the Geological Memoirs and so their depths have been extrapolated from the stratigraphical column from the published geological sheet No. 249

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7 Conclusions and Recommendations

The site for the proposed Taf Ely Learning Campus at Nantgarw near Pontypridd in South Wales is within an area affected by coal mining activity with numerous coal seams having been worked both beneath and in the vicinity of the site from the former Nantgarw Colliery within the South Wales Coalfield.

Coal mine records obtained from the Coal Authority indicates that the closest mine entries to the site were the ‘North’ and ‘South’ shafts from the former Nantgarw Collliery, located approximately 150 metres to the east of the site boundary.

These mine entries reached depths of up to 785 metres and records from the Coal Authority indicates that these shafts were infilled and reinstated with stone by January 1987. It is, however, recommended that these mine entries are located and identified to confirm their location in relation of the proposed works.

Numerous coal seams were extensively mined from these shafts both by ‘Pillar’ and ‘Stall’ techniques that adopted a number of narrow roadways driven into the coal seam to a predetermined boundary. Then two sets of roadways are driven at right angles to each other, and the seam is divided into a large number of square or rectangular pillars. These pillars are extracted at a later period.

Subsequently, this technique was replaced by ‘Long Wall’ mining techniques, which involved a full-extraction method for mining large panels of the coal seam in one operation by means of a long working face or wall. The workings advance (or retreat) in a continuous line, which may be several hundred metres in length. The space from which the coal has been removed (the gob, goaf, or waste) either is allowed to collapse (caving) or is completely or partially filled or stowed with stone and debris.

The recorded workings from the Nantgarw Colliery have taken place in the No. 8 Seam; 2 Foot 9 inch Seam, 4 Foot Seam (No.18), 4 Foot Seam (No.18), 6 Foot Seam (No. 22), 9 Foot Seam (No. 24), Yard / 7 Foot Seam, Standard 5 Foot / Gellideg Seam with the Colliery closing in late 1986.

It is considered that the risk from ground surface mine subsidence associated with these workings is low based on the depth that these coal seams were worked and the guidance provided within CIRIA SP32 Construction over Abandoned Mine Workings in relation to the potential migration of voids to the surface from the collapse of the mine workings.

This is based on the approach that considers the summation of the coal seams worked beneath the site, to be in this case approximately 15 metres thick and with the shallowest worked coal seam from surface being approximately 560 meters below ground level. Therefore, by adopting the conservative bulking factor of 10 to 1 the voids from these seams would only migrate approximately 150 metres and so still remain at a depth in the order of 400 metres below the site. Consequently, any voids from the workings beneath the site will not affect the proposed foundations to the proposed development.

The risk from shallow mine workings of the ‘Dirty’ and ‘Brithdir Rider’ seams that subcrop beneath the site at the interface with rockhead, is also considered to be low. This is because the depth to these mineral veins based on the site investigation undertaken by Soil Mechanics proved a minimum thickness of greater than 20 metres of ‘drift’ deposits at the site, which is considered too deep and with the high groundwater table would preclude their mining by ‘bell pit’ mining techniques and so it is deemed not necessary to undertake any rotary probe boreholes to investigate the potential of shallow mine workings at the site.

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Furthermore, a review of the site investigation records included within the Interpretative Report on the Site Investigation, Report No. J9045 dated December 2009 prepared by Soil Mechanics indicates that no voids where encountered within the boreholes that extended into the bedrock.

Finally, given the depth of mine workings beneath the site, it is considered that no special foundation measures are required as the risk of subsidence at the surface from the former mine workings is considered to be low.

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Appendix A

Site Location Plan

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Appendix B

Geological Maps: Drift and Solid

Appendix C

Coal Authority – Mining Report

Issued by: The Coal Authority, Mining Reports Office, 200 Lichfield Lane, Berry Hill, Mansfield, Nottinghamshire NG18 4RG ON-Line Service: www.groundstability.com - Phone: 0845 762 6848 - DX 716176 MANSFIELD 5

Person dealing with this matter: Paul Heap CUSTOMER SERVICES, Our reference: 00039911-09 LANDMARK INFORMATION GROUP LIMITED, Your reference: 28789365 ABBEY COURT UNIT 5/7, Electronic Ref: EME_00012325210006_005 EAGLE WAY, RRUID: 005.00012325210006 SOWTON INDUSTRIAL ESTATE, Date of your enquiry: 07 September 2009 EXETER, Date we received your enquiry: 07 September 2009 DEVON, Date of issue: 09 September 2009 EX2 7HY

This report is for the property described in the address below and the attached plan.

Coal and Brine Report Site At Coleg Morgannwg, Nantgarw Campus, Heol Yr Odin, Parc Nantgarw, Cardiff

This report is based on and limited to the records held by, the Coal Authority, and the Cheshire Brine Subsidence Compensation Board's records, at the time we answer the search.

Coal mining Yes

Brine Compensation District No

Information from the Coal Authority Underground Coal Mining Past The property is in the likely zone of influence from workings in 5 seams of coal at 570m to 970m depth, and last worked in 1962.

Any ground movement from these coal workings should have stopped by now. In addition the property is in an area where the Coal Authority believe there is coal at or close to the surface. This coal may have been worked at some time in the past.

Present The property is not in the likely zone of influence of any present underground coal workings.

Future The property is not in an area for which the Coal Authority is determining whether to grant a licence to remove coal using underground methods.

© The Coal Authority CON29M Non-Residential 00039911-09 Page 1 of 4 Printed:09 Sep 2009 The property is not in an area for which a licence has been granted to remove coal using underground methods. The property is not in an area that is likely to be affected at the surface from any planned future workings. However reserves of coal exist in the local area which could be worked at some time in the future. No notice of the risk of the land being affected by subsidence has been given under section 46 of the Coal Mining Subsidence Act 1991. Mine entries There are no known coal mine entries within, or within 20 metres of, the boundary of the property. Coal-mining geology At the surface, there are no known faults or other lines of weakness due to coal mining that have made the property unstable. Opencast Coal Mining Past The property is not within the boundary of an opencast site from which coal has been removed by opencast methods.

Present The property does not lie within 200 metres of the boundary of an opencast site from which coal is being removed by opencast methods.

Future The property is not within 800 metres of the boundary of an opencast site for which the Coal Authority is determining whether to grant a licence to remove coal by opencast methods. The property is not within 800 metres of the boundary of an opencast site for which a licence to remove coal by opencast methods has been granted. Coal-mining subsidence The Coal Authority has not received a damage notice or claim for the property since 1 January 1984. There is no current Stop Notice delaying the start of remedial works or repairs to the property. The Authority is not aware of any request having been made to carry out preventive works before coal is worked under section 33 of the Coal Mining Subsidence Act 1991. Mine gas There is no record of a mine gas emission requiring action by the Coal Authority within the boundary of the property. Hazards related to coal mining The property has not been subject to remedial works, by or on behalf of the Authority, under its Emergency Surface Hazard Call Out procedures.

Withdrawal of Support The property is not in an area for which a notice of entitlement to withdraw support has been published. The property is not in an area for which a notice has been given under section 41 of the Coal Industry Act 1994, revoking the entitlement to withdraw support.

© The Coal Authority CON29M Non-Residential 00039911-09 Page 2 of 4 Printed:09 Sep 2009 Working Facilities Orders The property is not in an area for which an Order has been made under the provisions of the Mines (Working Facilities and Support) Acts 1923 and 1966 or any statutory modification or amendment thereof. Payments to Owners of Former Copyhold Land The property is not in an area for which a relevant notice has been published under the Coal Industry Act 1975/Coal Industry Act 1994. Comments on Coal Authority information In view of the mining circumstances a prudent developer would seek appropriate technical advice before any works are undertaken.

Therefore if development proposals are being considered, technical advice relating to both the investigation of coal and former coal mines and their treatment should be obtained before beginning work on site. All proposals should apply good engineering practice developed for mining areas. No development should be undertaken that intersects, disturbs or interferes with any coal or mines of coal without the permission of the Coal Authority. Developers should be aware that the investigation of coal seams/ former mines of coal may have the potential to generate and/or displace underground gases and these risks both under and adjacent to the development should be fully considered in developing any proposals. The need for effective measures to prevent gases entering into public properties either during investigation or after development also needs to be assessed and properly addressed. This is necessary due to the public safety implications of any development in these circumstances.

Information from the Cheshire Brine Subsidence Compensation Board The property lies outside the Cheshire Brine Compensation District. Additional remarks This report is prepared in accordance with the Law Society's Guidance Notes 2006, the User Guide 2006 and the Coal Authority and Cheshire Brine Board's Terms and Conditions 2006. The report is compliant with Home Information Pack requirements.

The Coal Authority owns the copyright in this report. The information we have used to write this report is protected by our database right. All rights are reserved and unauthorised use is prohibited. If we provide a report for you, this does not mean that copyright and any other rights will pass to you. However, you can use the report for your own purposes.

Approximate position of property

Enquiry boundary These maps are reproduced from Ordnance Survey material with the permission of Ordnance Survey on behalf of the Controller of Her Majesty's Stationery Office. © Crown copyright. Unauthorised reproduction infringes Crown copyright and may lead to prosecution or civil proceedings. The Coal Authority. Licence number: 100020315. [2006]

Key

Approximate position of enquiry boundary shown

Appendix D

Coal Mine Abandonment Plans

CONTENTS

1 EXECUTIVE SUMMARY ...... 1 2 INTRODUCTION...... 2 3 SOURCES OF INFORMATION ...... 3 4 SITE DESCRIPTION ...... 4 4.1 Site Location ...... 4 4.2 Site History ...... 4 5 Ground Conditions ...... 5 6 Mine Workings ...... 7 6.1 Coal Mining Report ...... 7 6.2 Mine Workings – Envirocheck Report ...... 8 6.3 Coal Mine Abandonment Plans...... 8 7 Conclusions and Recommendations...... 12

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Tables Table 5-1 Conjectured Stratigraphical Success beneath the Site – Made Ground and Drift 5

Table 5-2 Conjectured Stratigraphical Success beneath the Site - Bedrock 6

Table 6-3 Coal Mine Abandonment Plans 11

Appendices Appendix A Site Location Plan Appendix B Geological Maps: Drift and Solid Appendix C Coal Authority – Mining Report Appendix D Coal Mine Abandonment Plans

1 EXECUTIVE SUMMARY

Coal mine records obtained from the Coal Authority indicates that the ‘North’ and ‘South’ shafts from the former Nantgarw Collliery, are located approximately 150 metres to the east of the site boundary, and that these mine entries were infilled and reinstated with stone by January 1987.

Numerous coal seams were extensively mined at depth from these shafts both by ‘Pillar’ and ‘Stall’ and by ‘Long Wall’ mining techniques both beneath and within the vicinity of the proposed Taf Ely Learning Campus site.

It is, however, considered that the risk from ground surface mine subsidence associated with these deep coal mine workings is low, whilst the risk associated with shallow unrecorded mine workings at rockhead is also considered to be low, due to the depth of the overlying Glacial Drift deposits and the high groundwater table at the site would preclude the extraction of the coal seams by ‘bell pit’ mining techniques and so it is deemed not necessary to undertake any rotary probe boreholes to investigate the potential of shallow mine workings at the site.

Given the depth of mine workings beneath the site, it is considered that no special foundation measures are required as the risk of subsidence at the surface from the former mine workings is considered to be low.

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2 INTRODUCTION

Gardiner and Theobald (G&T) commissioned Hyder Consulting UK Ltd (Hyder) to provide Professional Engineering Design Services for the proposed Taf Ely Learning Campus at Nantgarw near Pontypridd in South Wales.

As part of this commission, Hyder undertook a mine working risk assessment for the proposed site, with the following elements of this commission have been considered within this report:-

A review of desk study and ground investigation information incorporated within the Interpretative Report on the Site Investigation, Report No. J9045 dated December 2009 prepared by Soil Mechanics. A review of the Coal Mine Abandonment Records for the site held at the Mine Records office of the Coal Authority based in Mansfield, Nottinghamshire. A review of the Coal Mine Abandonment Records in relation to the guidance provided within CIRIA SP32 Construction over Abandoned Mine Workings. Define extent of the historical mine workings at the site. Provide recommendations for the proposed development in relation to mitigating the risk from ground subsidence associated with historic coal mine workings.

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3 SOURCES OF INFORMATION

In the course of research reference has been made to the following sources of information:

BGS Geological Map Sheet 249 for Newport. Solid and Drift Editions. BGS. Geological of the Country around Newport. Memoirs for Sheet No. 249 Interpretative Report on the Site Investigation, Report No. J9045 dated December 2009 prepared by Soil Mechanics. Healy, P. R and Head, J. M. 1984. CIRIA SP32 Construction over Abandoned Mine Workings. Coal Mine Abandonment Plans obtained from the Coal Authority. SWA3224 Sheet: Shaft Infilling Scheme – Nantgarw Colliery SWA3224 Sheet: New Sinking Shaft Record – Nantgarw Colliery SWR3026 Sheet. 6 Foot Coal Seam Abandonment Plan for Nantgarw Colliery. Scale 1 to 2500 SWA3215 Sheet. 9 Foot Coal Seam Abandonment Plan for Nantgarw Colliery . Scale 1 to 2500 dated November 1956 SWA3224 Sheet. Shaft Section for 9 Foot Coal Seam for Nantgarw Colliery. Scale 1 to 2500 dated December 1986 SWA3224 Sheet. 6 Foot Coal Seam for Nantgarw / Windsor Colliery. Scale 1 to 2500 dated December 1986 SWA1131 Sheet. 6 Foot Coal Seam for Nantgarw Colliery. Scale 1 to 2500 dated November 1973 SWA1016 Sheet. 4 Foot Coal Seam for Nantgarw Colliery. Scale 1 to 2500 dated October 1970 SWA1016 Sheet. No. 8 Seam for Nantgarw Colliery. Scale 1 to 2500 dated October 1970 SWA1250 Sheet. Standard 5 Foot or Gellideg Seam (No. 28 Seam) for Nantgarw Colliery. Scale 1 to 2500 dated January 1976 SWA3224 Sheet. 7 Foot or Yard for Nantgarw / Windsor Colliery. Scale 1 to 2500 dated December 1986 9274 Sheet 1 of 4. 6 Foot Coal Workings for Taff Rhonda Navigation Colliery – Nantgarw. Scale Two chains to 1 inch (1:1584) dated October 1927. 9274 Sheet 2 of 4. 4 Foot Coal Workings for Taff Rhonda Navigation Colliery – Nantgarw. Scale Two chains to 1 inch (1:1584) dated October 1927. 9274 Sheet 3 of 4. 2 Foot 9 inch Coal Workings for Taff Rhonda Navigation Colliery – Nantgarw. Scale Two chains to 1 inch (1:1584) dated October 1927. 9274 Sheet 4 of 4. 9 Foot Coal Workings for Taff Rhonda Navigation Colliery – Nantgarw. Scale Two chains to 1 inch (1:1584) dated October 1927. www.museumwales.ac.uk http://www.welshcoalmines.co.uk/GlamEast/Nantgarw.htm http://webapps.rhondda-cynon-taff.gov.uk/heritagetrail/taff/nantgarw/nantgarw.htm

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4 SITE DESCRIPTION 4.1 Site Location

The site for the proposed Taf Ely learning Campus is located within the Treforest Industrial Estate at Nantgarw near Pontypridd at National Grid Reference ST 117 857.

The site forms an undevelopment plot of land within the Industrial Estate with residential properties to the south and west, commercial units to the north and recreational, commercial and offices units to the east.

The River Taff meanders approximately 150 metres from the south-western boundary of the site.

A site location plan is presented on Drawing No. 0001-NE02987 in Appendix A. 4.2 Site History

A summary of the historical development at the site is included within the Interpretative Report on the Site Investigation, Report No. J9045 dated December 2009 prepared by Soil Mechanics. This report describes the mining history in the vicinity of the site.

From a review of the abandonment mine plans held at the mine records office of the Coal Authority in Mansfield, Nottinghamshire, coal seams have been worked both beneath and in the vicinity of the site from the nearby Nantgarw Colliery that was subsequently linked with the Windsor Colliery within the South Wales Coalfield.

From information provided on the Rhondda Cynon Taff Heritage website, the Nantgarw Colliery was one of the largest collieries in Taff Ely during the twentieth century. Thomas Taylor of Taylor’s Navigation Steam Company Ltd, Pontypridd, began the construction of the two shafts at the colliery in 1910 that reached depths of up to 785 metres making them the deepest pits to be sunk in the South Wales Coalfield up to that time.

In 1924, whilst employing more than 850 men, the colliery was sold to the Taff Rhondda Navigation Steam Coal Company, where the miners worked the ‘Four’ and ‘Six’ Foot coal seams. The company encountered difficult geological conditions and after three years of trying to work the mine they abandoned it in 1927. It remained unworked until the Powell Duffryn Steam Coal Co Ltd bought it, however, following further attempts to work the pit, it was put into a 'care and maintenance' situation.

In 1937, Powell Duffryn designed a development scheme to put Nantgarw Colliery back to work but this was delayed by the war. The development scheme was revived in 1946. On nationalisation of the mines in 1947, the National Coal Board (NCB) took up the scheme as its first major project of the newly formed South Western Division and invested £5 million into the colliery, both on modern surface constructions and modern mining methods. New coke ovens were opened in 1951 and production started once more in the colliery the following year.

Coal was worked successfully from 1952 until 1974. Nantgarw Colliery and Windsor Colliery, Abertridwr were then combined as a single production unit. The colliery made a good recovery after the 1984/5 miners strike but failed to survive the huge closure policy of the time and was subsequently closed in November 1986.

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5 Ground Conditions

BGS Geological Map Sheet 249 Drift and Solid Editions were reviewed as part of this study and indicates that the site for the proposed Taf Ely learning Campus at Nantgarw near Pontypridd in South Wales comprises ‘drift’ deposits in the form of Alluvium associated with the nearby River Taff overlying Glacial sand and Gravel and Glacial Till deposits.

The ‘solid’ geology comprises the Lower Pennant Measures from the Upper Coal Measures (Caroniferous). The Lower Pennant Measures typically comprises an interbedded sequence of sandstones, mudstones, coal seams and seatearth.

The ‘Dirty’ and ‘Brithdir Rider’ seams are shown to subcrop beneath the site at the interface with rockhead, striking approximately WNW-ESE and dipping towards the northeast. The site is located approximately 100 metres east of the ‘Daren-Ddu fault’ that trends in a north-west to south-east orientation, whilst the site is 75 metres north of the Nantgarw Thrust Fault.

An extract for the drift and solid geological maps for the site are presented on Drawing No. 0002-NE02987 and 0003-NE02987, respectively in Appendix B.

The area in the vicinity of the site has been extensively mined over a long period of time. Recorded workings have taken place in the No. 8 Seam; 2 Foot 9 inch Seam, 4 Foot Seam (No.18), 4 Foot Seam (No.18), 6 Foot Seam (No. 22), 9 Foot Seam (No. 24), Yard / 7 Foot Seam, Standard 5 Foot / Gellideg Seam from Nantgarw / Windsor Colliery.

The conjectured stratigraphical succession for the Made Ground and Drift deposits provided within Table 5-1 is based on the proven ground conditions recorded during the site investigation undertaken by Soil Mechanics between October and November 2009.

Seam of strata base Min. Thickness (m) Min. Depth (m)

Made Ground 2.90 2.90

Drift 22.50 25.40

Table 5-1 Conjectured Stratigraphical Success beneath the Site – Made Ground and Drift

Reference should be made to the Interpretative Report on the Site Investigation, Report No. J9045 dated December 2009 prepared by Soil Mechanics for a detailed interpretation on the ground conditions encountered during the site investigation. The conjectured stratigraphical succession through the bedrock is provided within Table 5-2 and is based on the geological sequence recorded within the ‘South Shaft’ for the Nantgarw Colliery. An exception is the depth noted for the ‘Dirty Coal’ that is anticipated to subcrop at rockhead and so is noted below at the minimum depth to rockhead as proven from the ground investigation undertaken by Soil Mechanics between October and November 2009. The information shows for clarity only the mineral and coal seams; intervening strata are not shown.

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