Varteg Hill Reclamation & Coal Recovery Scheme, Blaenavon, South Wales
Hydrogeological and Contaminated Land Assessment
Interpretative Report
Amended by: …………………………………………… Checked by:
Philip Smart Murtala Bashir
Technical Director (Hydrogeology) Principal Hydrogeologist
Approved by: ……………………………………………
Claire Parkinson
Regional Director
Varteg Hill Reclamation & Coal Recovery Scheme, Blaenavon, South Wales Hydrogeological and Contaminated Land Assessment - Interpretative Report
Rev No / Comments / Checked by / Approved by / Date0 / Final – Updated for inclusion in revised ES / 22 April 2009
1 / Modified final to support amended scheme / mb / clp / 9 October 2014
Colmore Plaza, Colmore Circus Queensway, Birmingham, B4 6AT
Telephone: 0121 262 1900 Website:http://www.aecom.com
Job No 60327633 Reference 03 – Final Date Created August 2014
This document has been prepared by AECOM Limited for the sole use of our client (the “Client”) and in accordance with generally accepted consultancy principles, the budget for fees and the terms of reference agreed between AECOM Limited and the Client. Any information provided by third parties and referred to herein has not been checked or verified by AECOM Limited, unless otherwise expressly stated in the document. No third party may rely upon this document without the prior and express written agreement of AECOM Limited.
f:\projects\geo - environmental - 60327633 varteg occs\03 execution\03 documents\03 geo-report 2014 report\word version\varteg hill reclamation geo-environment assessment report final 09102014.docx
Table of Contents
1 Introduction 4
1.1 Instruction 4
1.2 Project Objectives 4
1.3 Sources 4
1.4 Limitations 5
2 Site Location and Background Information 8
2.1 Site Location and Description 8
2.2 Environment Agency Conditions 8
2.3 History of the Site 9
2.4 Proposed Site Works 10
3 Environmental Setting 12
3.1 Topography and Hydrology 12
3.2 Geology 12
3.3 Mining 14
3.4 Hydrogeology 17
3.5 Hydrology 18
4 Ground Investigation Works 23
4.1 Methodology 23
4.2 Boreholes 23
4.3 Trial Pits 23
4.4 Sampling 24
4.5 Groundwater Instrumentation 24
5 An Interpretation of the Results of the Ground Investigation – Geology 27
5.1 Geology 27
5.2 Borehole BH1 27
5.3 Borehole BH2 28
5.4 Borehole BH3 28
5.5 Borehole BH4 28
5.6 Borehole BH5 29
6 6 An Interpretation of the results of the ground investigation - Hydrogeology 31
6.1 Introduction 31
6.2 Groundwater levels 31
6.3 Summary 33
6.5 Groundwater Quality 35
6.6 Surface Water 37
7 An Interpretation of the Results of the Ground Investigation – Ground Contamination 40
7.1 Introduction 40
7.2 Data Assessment 41
7.3 Leachate Test 44
7.4 Statistical Analysis 46
7.5 Summary 47
8 Conceptual Site Model 50
8.1 Introduction 50
8.2 Conceptual Model of Hydrology and Hydrogeology 50
8.3 Conceptual Model for Contaminated Land 51
9 An Assessment of the Impact of the Proposed Scheme on Controlled Waters 54
9.1 Hydrology and Hydrogeology 54
9.2 Proposed drainage strategy 57
9.3 Water treatment areas 58
9.4 Drainage-related site activities 59
9.5 Licensing 60
9.6 Monitoring 60
10 An Assessment of the Impact of the Proposed Scheme on Human Health 62
10.1 Contaminated Ground 62
10.2 Mitigation 62
11 Conclusions and Recommendations 67
11.1 Summary 67
11.2 Conclusions 67
11.3 Recommendations 68
List of Figures
Figure 2.1 Plan showing site location
Figure 2.2 Plan showing the site location
Figure 3.1 Plan showing the approximate locations of shafts and adits
Figure 4.1 Plan showing locations of exploratory holes and lines of section
Figure 5.1 Geological cross-section through the proposed coal extraction area (north-south)
Figure 5.2 Geological cross-section through the proposed coal extraction area (north west-south east)
Figure 6.1 Groundwater hydrograph for borehole BH1
Figure 6.2 Groundwater hydrograph for piezometer BH2a
Figure 6.3 Groundwater hydrograph for piezometer BH2a October and November 2005
Figure 6.4 Groundwater hydrograph for piezometer BH2b
Figure 6.5 Groundwater hydrograph for piezometer BH4a
Figure 6.6 Groundwater hydrograph for piezometer BH4b
Figure 6.7 Groundwater hydrograph for borehole Bh5
Figure 6.8 Groundwater hydrographs for piezometer BH2a, Bh4a and BH5 equipped with data loggers
Figure 6.9 Plan showing the groundwater contours for the Upper Sandstone (July 2006)
Figure 6.10 Plan showing the groundwater contours for the Gellideg Rock (July 2006)
Figure 6.11 Plan showing the water quality monitoring points
Figure 7.1 Plan showing soil contamination
Figure 8.1 Schematic Hydrogeological conceptual site model of the proposed extraction area
Figure 9.1 Plan showing the extent of the workings where groundwater ingress is anticipated
Figure 9.2 Plan showing the proposed monitoring scheme
List of Tables
Table 3.1: Regional Geology
Table 4.1 Laboratory Testing Suites
Table 4.2: Details of Piezometers
Table 6.1 Groundwater monitoring installations
Table 6.2: Groundwater levels
Table 6.3 Water quality analytical suite
Table 6.4 Groundwater quality 2006
Table 6.5 Surface water quality
Table 7.1: Summary of the Laboratory Analysis of the Soil Samples
Table 7.2: Summary of leach test results
Table 7.3 Summary results of the statistical analysis
Table 9.1 Catchment areas of new Water Treatment Areas.
Table 10.1 Impact Assessment and Proposed Mitigation Measures
Appendices
Appendix A - Copies of EA/NRW correspondence dated 18 November 2009 and 8 July 2014
Appendix B - Plan showing the restoration proposals
Appendix C - Plans showing the extent of former underground coal workings
Appendix D - Borehole logs 1979
Appendix E - Rainfall and evaporation data
Appendix F - Ground Investigation
Appendix G - Geophysical Report
Appendix H - Laboratory data sheets for the water quality analyses
Appendix I - Laboratory data sheets for soil samples
Appendix J - Statistical analysis of soil laboratory testing results
Appendix K - Proposed environmental monitoring scheme
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Introduction
AECOM Varteg Hill Reclamation & Coal Recovery Scheme, Blaenavon, South Wales 6
1 Introduction
1.1 Instruction
AECOM Limited (AECOM) is instructed by Harmers on behalf of Glamorgan Power Co Ltd, to provide an interpretative report in respect of hydrogeological and contaminated land issues associated with the proposed Varteg Hill Reclamation and Coal Recovery Scheme site, near Blaenavon. The report will support the Environmental Statement which will accompany the revised planning application for land reclamation and coal recovery at Varteg.
A report on the hydrogeological and contaminated land elements of the proposed scheme initially was prepared in September 2006 by Faber Maunsell Limited (now AECOM) in support of the original Environmental Impact Assessment for the proposed development.
Following the implementation of Minerals Technical Advice Note 2: Coal in 2009 and concerns raised by the Council leading up and a planning inquiry held in February 2012, it was necessary to reduce the proposed coal extraction area from 14ha to 11.6 ha. Subject to the implementation of appropriate conditions, the Planning Inspector recommended that planning permission should be granted. This was supported by the first Welsh Minister’s Decision letter dated 4th February 2013 who was minded to grant permission subject to revisions to the Section 106 Agreement. However, this decision was over-ruled by the second Welsh Minister’s Decision Letter dated 22 November 2013, principally in respect of the lack of consideration of alternatives for carrying out the land reclamation other than the extraction of coal and the adequacy of the Unilateral Undertaking in respect of the Restoration Bond.
Whilst the outcome of the Public Inquiry had no significant implications in respect of hydrogeological and contaminated land aspects of the scheme, the initial report on the contaminated land and hydrogeological conditions has been reviewed and updated to address new guidance and documents issued since 2006. The report also addresses the points raised by Natural Resources Wales (NRW) in the response to the request for an amended scoping opinion dated 8 July 2014.
1.2 Project Objectives
The principal project objectives have been identified and are listed below:-
· Review published and unpublished sources of information and data pertaining to the site, including historical Ordnance Survey maps;
· Construct a conceptual model of the site and its environs focussed particularly on hydrogeology and contaminated land;
· Present the ground investigation works, interpret and evaluate the geochemical testing of soil samples, surface water and groundwater monitoring results in order to clarify the groundwater and contaminated land conceptual models;
· Undertake qualitative and quantitative risk assessments of the potential impacts of the development on controlled waters and on human health; and;
· Provide proposals for water management and pollution control.
1.3 Sources
The following sources of information have been consulted in the preparation of this report:-
· Viponds Top and Washery Spoil Heaps: Report on the investigation into security of Tips 527 and 528. Sir William Halcrow & Partners, October 1979;
· Viponds Top and Washery Tips No. 527 and 528: Report No. 2 on disused colliery spoil heaps. IMCL. Reference 527/32/3, May 1994;
· Landmark Envirocheck Report reference EC11507571, June 2005;
· British Geological Survey (BGS) 1:50,000 sheet 232, Abergavenny and 1:10,560 scale map SO20NE;
· A reserves assessment on land at Varteg, Abersychan, near Pontypool. Blandford Consulting. Reference BC/MC/05.02.02, 2002;
· Cementation Co Ltd, Brace’s pit drillers’ logs, 1996, copy held at Blandford Consulting archives;
· NCB Opencast Executive, Eastern Area Office, Brace’s Pit borehole schedules, copy held at Blandford Consulting archives;
· NCB Opencast Executive South West Region No. 7. Prospecting Site Area: Brace’s Pit, Site No. 070842, Scale 1:2500, Drawing No. 07D455. Annotated plan showing constraints and prospecting borehole locations. 29 September 1964;
· NCB Opencast Executive South West Region No. 7. Prospecting Site Area: Aqueduct, Site No. 070852, Scale 1:2500. Annotated plan showing limits of previous opencast workings in the vicinity of the Varteg Hill Reclamation and Coal Recovery Scheme site. Undated;
· Anon. Varteg WA/8/96. Cross-sections 1-1, 2-2 and 3-3 and vertical section, 1:500. Undated;
· Report on Geophysical Logging at Varteg Hill R&CR Scheme. European Geophysical Services, August 2005;
· Varteg Hill Reclamation & Coal Recovery Scheme: Water Features Survey, Faber Maunsell Limited, March 2004;
· Varteg Hill Reclamation & Coal Recovery Scheme, Blaenavon, South Wales: Phase I – Desk Study, Faber Maunsell Limited, September 2005.
· Rainfall and evapotranspiration data for the area provided by the Meteorological Office;
· Groundwater level monitoring information for the period August 2005 and September 2006;
· The results of groundwater and surface water quality monitoring in February and July 2006;
· A site walkover in July 2014; and,
· Correspondence from Torfaen CBC and the Environment Agency/NRW between February 2005 and July 2014.
1.4 Limitations
This report has been prepared on behalf of and for the sole use of Harmers and its client Glamorgan Power Co Ltd (the Client). Any third party relies on this report solely at its own risk unless it is the beneficiary of a warranty executed by AECOM Ltd specifically for the purposes of creating a duty to it.
The interpretation of the hydrogeological and geological conditions at the site is based on an assessment of published information, ground investigation and laboratory results, and on an extrapolation of point-source information using geological experience. There is a degree of subjectivity in any interpretation.
The effects of ground and water borne contamination on the environment are constantly under review and authoritative guidance values are potentially subject to change. The conclusions presented herein are based on the guidance available at the time this report was prepared. No liability can be accepted for the retrospective effects of any changes or amendments to the legislation or guidance.
This report addresses the hydrogeological conditions at the site and potential land contamination arising through historical industrial use of the site. The report does not consider ground engineering aspects of the proposed development, including effects of the proposed excavations on the stability of adjacent areas of backfilled spoil.
The copyright in this document (including its electronic form) shall remain vested in AECOM Ltd but the Client shall have a licence to copy and use the document for the purpose for which it was provided by AECOM. This document shall not be reproduced in whole or in part or relied upon by third parties for any use whatsoever without the express written authority of AECOM.
Site Location and Background Information
AECOM Varteg Hill Reclamation & Coal Recovery Scheme, Blaenavon, South Wales 10
Capabilities on project: Environment
2 Site Location and Background Information
2.1 Site Location and Description
The site of the proposed coal recovery and land reclamation scheme occupies land immediately west of the village of Varteg, beside the B4246 Varteg Road, running from Blaenavon in the north to Abersychan in the south. It is centred on approximate National Grid Reference (NGR) SO26150610, as shown on Figure 2-1.
The site comprises two main land holdings joined by a narrow isthmus following the bed of a former mineral railway track, currently used as access to farms to the west (Figure 2-2). The larger eastern land holding (“Main Area”) incorporates the proposed coal extraction site and the site facilities and includes the former drift mine compound, spoil tips and relatively flat-lying poorly – drained grazing land. This part of the site covers an area of approximately 62ha of which the proposed coal extraction site is approximately 11.6ha.