60 70 80 90 500000 10 20 30 40 50 60

BGS maps covering and the Boroughs of Barnet, HYDROCARBONS PEDL36 Enfield, Harrow and Hillingdon CANUK Conventional Oil and Gas

ASHWELL Hertfordshire occupies a tract of land beneath which Palaeozoic basement lies at shallow depth. Permian and 204 205 Mesozoic rocks are relatively thin, with the outcrop of overlying Chalk widespread across the county. Palaeogene deposits of the London Basin crop out along the southeastern areas of the county.

Few seismic lines have been acquired in the county and the and Ashwell hydrocarbon exploration boreholes 220 221 222 both only just lie within the county. Up to early 2002, no licence blocks are wholly located within the county. PEDL36 (operated by CANUK) extends into the extreme NE of the county. As of July 2002 this licence appeared to 40 HERTFORDSHIRE have been relinquished. At present therefore, Hertfordshire appears to offer little or no hydrocarbon potential. 40

and Mine Gas Drainage, Coal Mine Methane and Coalbed Methane (CBM) potential Report 104

The county shows negligible potential for mine gas drainage, coal mine methane and CBM development. Report 52 NW LONDON BOROUGHS Report 46 Licensing

(comprising Hertfordshire and London Boroughs TRING 1 The Department of Trade and Industry grants licences for exclusive rights to explore for and exploit oil and gas 239 240 onshore within Great Britain. The rights granted by landward licences do not include any rights of access, and the of Barnet, Enfield, Harrow and Hillingdon) licensees must also obtain any consent under current legislation, including planning permission. Report 69 Report 67 Mineral Resource Information in Support of National, 200 Report 71 Report 112 Regional and Local Planning Mineral Resources 238 255 Scale 1:100 000 Arlesey Road Sand Pit (Sg) ENFIELD Hydrocarbon well Report 12 BARNET Holwell Sand Pit (Sg) Anstey Chalk Compiled by A.J. Benham, A.N. Morigi, A.J. Bloodworth, D.G. Cameron, D.J. Evans, HARROW G.K. Lott and D.E. Highley. Petroleum Exploration and Development Licence Quarry (Ch) PEDL issued under the Petroleum (Production) Act 1934 Project Leader: D.E. Highley. (as at March 2002) Greystone Limeworks (Ch) HILLINGDON Digital cartography by N.A. Spencer, British Geological Survey. 500 550 Published 2003. Butts Hill (Ch) 256 30 South End of 30 Railway Station (Ch) This map comprises part of a summary of the 'Mineral Resources of the East of 269 270 Region'. For further imformation see www.mineralsUK.com BRICK CLAY West Mill Chalk Pit 'Brick clay' is the term used to describe clay and shale used predominantly in the manufacture of bricks and, to a lesser extent, roof tiles St Ippollitts (Ash Brook) (Sg) Pit (Sg) (Down Hall Chalk Pit) (Ch) BIBLIOGRAPHIC REFERENCE and clay pipes. These clays may sometimes be used in cement making, as a source of constructional fill and for lining and sealing landfill sites. The suitability of clay for the manufacture of bricks depends principally on its behaviour during shaping, drying and firing. This will Report 12 Benham, A.J., and 6 others. 2003. Mineral Resource Information in Support of National, Regional and Local Planning: Hertfordshire and 239 1:25 000 map published (Industrial Minerals dictate the properties of the fired brick such as strength and frost resistance and, importantly, its architectural appearance. 1:63 360 and 1:50 000 map published NW London boroughs (comprising Hertfordshire, London Boroughs of Barnet, Enfield, Harrow and Hillingdon). British Geological Survey Assessment Sand and Gravel Resource Map)

Commissioned Report CR/03/075N Most facing bricks, engineering bricks and related clay-based building products are manufactured in large automated factories. These Vicars Grove (Sg) represent a high capital investment and are increasingly dependent, therefore, on raw materials with predictable and consistent firing Current digital availability of these sheets can be found on the British Geological Survey website, www.bgs.ac.uk Production of this map was commissioned and funded by the Office of the characteristics in order to achieve high yields of saleable products. Blending different clays to achieve improved durability and to provide a range of fired colours and textures is an increasingly common feature of the brick industry. Continuity of supply of consistent raw Deputy Prime Minister (Contract MP0677). materials is of paramount importance.

The sole remaining brickworks in Hertfordshire is located at near . This is a relatively small works that Stortford Lime Works produces mechanically made, 'soft-mud' facing bricks, although about 20 per cent of production is in the form of hand-made stock Langley Sidings Kiln Farm Pit (Sg) (Bishops Stortford) (Ch, Fi) bricks. The bricks are made from the mottled clays of the Reading Formation and Clay-with-Flints. These deposits are broadly similar, although varied in composition, because one (Clay-with-Flints) is largely derived from the other: they are therefore shown as a single (Depot) (CR) Chalk SAND & GRAVEL resource. However, the occurrence at Bovingdon is exceptional rather than typical. For this reason, and because of their patchy Pit (Hadham Lime) (Ch) occurrence and variable nature and thickness (up to 20 m), these deposits are shown as a resource in the Hemel Hempstead area only. Westland Green (Sg) Superficial deposits Frogmore Lodge (Lordship Estate) (Sg) Dowsetts Farm (Ch, Sg) Side Hilly (Sg) Sub-alluvial: Inferred resources The Cock Public House, r/o Rookery Pit (Frogmore Hall ( Road) (Sg) (Including Rookery Pit)) (Sg) 20 Plashes Farm Borrow Pit (Sg) 20 Sub-alluvial: Indicated resources (only in area assessed by BGS) Twyfordbury (Sg) Barwick Ford (Sawtree Wood) (Sg) Three Hills ( Heath) (Sg) Ware ( River terrace deposits Codicote Heath Pits (Sg) (Sg) Farm) (Sg) Three Hills (Codicote Heath) (Sg) Stoney Hills (Stoney Hills Brickworks) (Cl) River terrace deposits: Concealed (only in area assessed by BGS) Hadham Towers Poles Lane (Pallett’s Pit) (Sg) (Ashbourne Farm) (Sg) Southend Farm (Sg) (Oakhill) (Sg) Westmill (Downfield Farm) (Sg) Glaciofluvial sand and gravel (including Kesgrave Sand and Gravel) Westmill Farm (Sg) Poors Land (Sg) Codicote Chalk Pit (Ch) Rickneys (Sg) Golf Course (Sg) River Farm (Sg) Ware Quarry (Gentlemans Field, Garrick Land, Middle Field) (Sg) Waterford (Sg) Marshes (Kecksy’s Bridge) (Sg) Glaciofluvial sand and gravel: Concealed (only in area assessed by BGS) Hill Farm (Sg) Mortimer Road (Pallett’s depot) (Sg) Waterford (Bramfield Ware Quarry (Walton Road, Brazier Landfill site) (Sg) Plateau (Sg) Lane) (Sg) Ware Quarry (Park Road, Brazier Landfill site) (Sg) Sawbridgworth (Sg) Pitstone (Ch) Digswell Hill Brickworks (Sg, Cl) Waterford Pit (Sg) Ware Park Ware Quarry (Old Pit Park Road) (Sg) Glacial sand and gravel deposits Blackbridge (Sg) Quarry (Sg) High Wych (Rowney Gardens) (Sg) (Sg) Broad Oak End (Sg) (Sg) Gaddesden Row Brickpit Great Molewod Gravel Chadwell Hill (Ware Road Chalk Pit) (Ch) Cole Green (Holwell Pit (Molewood) (Sg) Amwell Quarry (The Thifts) (Sg) (Butterfields Pit) (Cl) Park Wood) (Sg) Alston Road (Rowenbury) (Sg) Glacial sand and gravel deposits: Concealed (only in area assessed by BGS) Bulbourne Road (Ch) Ware Road (Sg) Amwell Quarry (Sg) Twentieth Mile (Twentieth Amwell Quarry Redricks Lane (Sg) Mile Gravel & Brickworks) Boundary of area assessed for sand and gravel at the indicated Old Station Yard (Old Foxholes Farm (Sg) Presdales (Sg) (Sheepcote Farm) (Sg) Hollingson Meads (Sg) Station Road) (Topsoil) (Sg, Cl) St Margaret’s (Sg) Pogdens Wood (Sg) resource level Birchall Lane (Sg?) Pole Hole (Pole Hole Farm) (Sg) Goslings Stadium (Sg) (Sg) Land at Eastwick (Sg) Approximate southern/western limit of thick glacial deposits on Hempstead Road (Sg) Cole Green (Holwell Hyde Farm) (Sg) Rye Meads Depot (CR) Ryegate Farm (Rye Meads) (Sg) Redbournbury ( glaciofluvial and river terrace deposits Woodhall Farm (Sg) Water Hall (Sg) Rye Meads (Sg) Treatment Plant) (Ch) Rye Meads (STW) (Sg) 10 BUILDING STONE Hatfield Quarry (Coopers 10 Jersey Farm (Evans Farm) (Sg) Rye Road (off Rye Road) (Sg) Green Lane) (Sg) Broadwater (Sg) Water Hall (Pollards) (Sg) Bramble Lane (Sg) The Cretaceous and Palaeogene successions of Hertfordshire have yielded a limited number of stones for building purposes. Both Chalk Rye House (Sg) CHALK Widmore Brickworks (Cl) block and flint nodules from the Upper Cretaceous have been extensively used in the past for local building purposes. Berkhamsted Admirals Walk (The Lynch) (Sg) Brickworks Bedwell Park (Ch, Sg) Road (Rye House) (Sg) Brick Works (Cl) Culverwood (Sg) Chalk: Higher purity (93-98% CaCO 3) White Chalk Subgroup (Shootersway Charlton Quartz-cemented sandstones (or Sarsen stones), together with the conglomeratic beds of the Palaeogene succession (Hertfordshire Hatfield Quarry (Sg) Hoddesdonbury (Sg) Mead (Sg) Puddingstone) were also once widely worked for building material and are found extensively in older buildings in the county. There are Brickworks) (Cl) SAND & GRAVEL Farm (Borrow Pit) (Cl) (Cock Lane, Broxbournebury) (Sg) Admirals Walk (Sg) no building stone quarries currently operating. Smallford Pit (Colney Chalk: Low purity (<93% CaCO3 ) Grey Chalk Subgroup Heath, Butterwick & Blackfan Wood (Sg) Cock Lane Dobbs Weir (Sg) Sand and gravel are defined on the basis of particle size rather than composition. In current usage, the term 'gravel' is used for material that is coarser than 5 mm, with a maximum size of 40 mm, and the Broadway Farm (Sg) Sheepshyde Farm (Tyttehanger Smallford Farm) (Sg) Park) (Sg) (Broxbournebury) term 'sand' for the material that is finer, but coarser than 0.075 mm. Most sand and gravel is composed of particles that are rich in silica (quartz, quartzite and flint), but other rock types may occur locally. Acorn Brickworks (Cl) Swing Gate Lane Borrow (Sg) Mill Lane (Sg) BRICK CLAY Pit (Bottom Farm) (Sg) Gravel Pit (Sg) Tyttenhanger (Sg) Carneles Green (Sg) Hoddesdon The principal uses of sand are as fine aggregate in concrete, mortar and asphalt. The main use of gravel is as coarse aggregate in concrete. Substantial quantities of sand and gravel may also be used for CHALK Vale Farm Limex (Ch) Tyttenhanger Quarry (land Sewage Works (Sg) construction fill. Reading Formation/Clay-with-Flints (Hemel Hempstead area only) Borrow Pit (Sg) east of Coursers Road) (Sg) Church Lane (Sg) Chalk is a relatively soft, fine-grained, white limestone, consisting mostly of the debris of planktonic algae. It occurs as bedrock Slipe Lane (Wormley/ Hertfordshire produced almost 1.7 million tonnes of sand and gravel in 2001 and has estimated permitted reserves of just over 10 million tonnes. Recent production figures may be seen on the inset graph. Sheethanger (Ch) Potters Crouch (Sg) Park Farm (Sg) throughout most of the county and generally crops out above the 90 m contour in the north and north-west of the county, especially in Turnford Marsh) (Sg) Sand and gravel resources occur in a variety of geological environments. In Hertfordshire and the northwest London boroughs these resources occur within the category of superficial or 'drift' deposits, the Chiltern uplands where the land rises to over 160 m. Part of this higher ground falls within the Chilterns Area of Outstanding Natural Millhouse Lane (Sg) Napsbury Turnford Marsh (Sg) Beauty (AONB). Elsewhere in the county, younger rocks and superficial deposits conceal the chalk. Tyttenhanger (Extension) (Sg) Nunnery Farm (Mill Lane) (Sg) subdivided into glaciofluvial sand and gravel, glacial sand and gravel, river terrace deposits, and sub-alluvial deposits. MINERAL PLANNING PERMISSION (as at 01/04/03) Bovingdon Airfield (Cl) Radlett Airfield (Sg) Hospital (Sg) Toms Lane (Sg) Bell Lane () (Sg) Turnford Marsh (Sg) Source: Mineral Planning Authorities The White Chalk Subgroup (formerly Middle and Upper Chalk) varies from 60 m to about 79 m thick in central Hertfordshire and Holt Farm (Sg) South of Bell Lane (Sg) Seventy Acres (Cheshunt Junction) (Sg) Superficial deposits Bovingdon Brick Works comprises higher purity material (93-98% CaCO3 excluding chalk with flint) than the underlying Grey Chalk. Layers of large flint nodules Lane (Bell Lane) (Sg) (Pocket's Dell) (Cl) Moor Mill (Sg) Cheshunt Junction (Seventy Acres) (Sg) Parts of the area assessed for sand and gravel by BGS resource surveys are identified on the map. Resources shown here are taken from these maps where available. In these areas, the possible extent of are common in the White Chalk Subgroup. The White Chalk Subgroup occurs as bedrock under most of the county north of a line Bovingdon Brick Works (Cl) Black Boy Pit (Sg) Castle Chalk Pit Surface planning permission (valid and expired) All Saints Pastoral (Sg) Hooks Marsh (Sg) sand and gravel concealed beneath till and/ or other material is shown. These indicated resources were defined by overburden to mineral ratios. Outside these areas, available data are more limited. running through and , although much of it is covered by superficial deposits. South of this line, Chalk outcrops only Sunderlands Meadows (Sg) () (Ch, Fi) Turnershill Marsh (Seventy Acres, Cheshunt Junction) (Sg) along the sides of the valleys of the rivers Lea and Ash near Hertford, and the Colne valley. Shenleybury Farm (Sg) Turnershill Marsh (Sg) Generally, only exposed sand and gravel is defined, although sub-alluvial resources of sand and gravel occurring beneath modern river flood plains may be extensive in some places. In addition, narrow Netherwylde Farm (Sg) Harperbury Hospital (Sg) Wharf (Sg) (< 200 m) spreads of sub-alluvial deposits are mainly excluded from the map. Their limited width is likely to preclude economic working of any sand and gravel present.

The Grey Chalk Subgroup (formerly Lower Chalk) outcrops in the north and far west of the county. It generally contains more Old Parkbury (Sg) Theobalds Lane (Sg) Cheshunt Marsh (Sg) Glaciofluvial sand and gravel MINERAL WORKINGS interbedded calcareous mudstone than the overlying White Chalk and is of lower purity (generally <93% CaCO3). It has been worked in Flaunden Quarry (Springview Farm) (Ch) Harper Lane (Sg) the past as a raw material for cement manufacture. Kytes Estate (Sg) Road (Sg) Harper Lane (CR) Bulls Cross Farm (Sg) These are the most widespread sand and gravel deposits. They broadly correspond to the Westmill Gravel and Westland Green Gravel Formations in Hertfordshire and their downstream equivalent in 2 000 Panshanger Active site Essex and Suffolk, the Kesgrave Formation. The deposits were laid down during successive cold phases between about 1.5 and 0.5 million yrs BP (up to the beginning of the Anglian Glaciation) in braided 2 000 00 Although in the past there were many sites working chalk, essentially for local use, there are currently only three working chalk quarries Munden Estate (Sg) Ramney Marsh West (Enfield Lock) (Sg) 00 in Hertfordshire; Anstey, Bedwell, and Codicote quarries produced a combined total of 31,000 tonnes of chalk in 2000. Great Westwood (Sg) Ramney Marsh East rivers; the main swathe represents ancestral deposits of the River Thames which formerly flowed north-east across the area. It is probable that locally the upper part of the unit has been reworked by Ramney Marsh North (Enfield Lock) (Sg) (Enfield Lock) (Sg) meltwaters issuing from the Anglian ice-sheet but such reworking has not significantly modified the composition of the deposits. Ramney Marsh South (Sg) Sheethanger Inactive (including sites not yet worked), Hall Farm The Chalk is a major aquifer and is the most important source of groundwater in the county. Moses Dell (Kendall Brickworks) (Cl) Forty Hill (Enfield worked-out and/or restored site (SW of A41) (Sg) The Dell (Forty Hill) (Sg) Crematorium) (Sg) The deposits form a semi-continuous sheet across the county comprising 5-15 m of clean pale coloured sands and pebbly sands with subordinate gravels. The clasts present are rounded quartz, quartzite Great Westwood (Sg) and well-rounded flint in sub-equal proportions together with small amounts of angular-nodular flint and rare volcanic lithologies. The sand fraction is sharp; predominantly medium angular to sub angular Winfield Site (Sg) Bushey Hall Farm (Sg) Carterhatch Lane East (Sg) Forty Hill Brickworks quartz with flint. Active rail aggregate depot Patchets Equestrian (Patchetts Green) (Sg) (Hoe Lane) (Cl, Sg) Ladbroke Mercury Hotel (Sg) PLANNING PERMISSIONS FOR MINERAL EXTRACTION Cassiobridge (Sg) The dashed line shown on the map divides two distinct areas in which the unit occurs. To the north of the line the deposits are mainly overlain by substantial thicknesses (up to 20 m, average 8 m) of Little Bushey Lane (Sg) Anglian glacigenic deposits (mainly till), whilst to the south they are generally present at, or near, surface. Crown Brickworks (Cl Sg) Sg Sand & gravel Fi Flint Patchetts Green Farm (Sg) The extent of all known extant and former planning permissions for the extraction of minerals is shown on the map, irrespective of their Glacial sand and gravel current planning or operational status. The polygons were supplied digitally by Hertfordshire County Council or were subsequently Brimsdown (Sg) Cl Common clay & shale CR Crushed Rock digitised by BGS from Plotting Sheets and other documents supplied by Hertfordshire County Council and the London boroughs of This category comprises waterlain sands and gravels deposited in close proximity to the Anglian ice-sheet that covered most of the northern half of Hertfordshire. Barnet, Enfield, Harrow and Hillingdon and any queries regarding the sites shown should be directed to these authorities at the Catlips Farm Borrow Pit (Sg) Conduit Lane (Sewage Ch Chalk addresses shown below. The polygons cover active, former and restored mineral workings and, occasionally, unworked deposits. Works, M25 Borrow Pit) (Sg) These deposits reach thicknesses of between 2-8 m when fringing the glaciofluvial Kesgrave deposits in the centre of the county, but increase in thickness further to the north and north-west where they

Croxley Hall Farm (Sg) Pickets Lock (Sewage Works) (Sg) reach on average between 20-30 m within incised river valleys. In the Hitchin and area, glacial sand and gravel deposits reach up to 80 m in thickness within the deeply incised Cam buried Planning Permissions represent areas where a commercial decision to work a mineral has been made, a successful application has been Merchant Taylors valley. Deposits are commonly located along the valleys of the rivers Lea and Mimram, and in patches on the high ground around . They generally rest on bedrock, but in places are underlain by ENVIRONMENTAL DESIGNATIONS (as at 30/04/03) dealt with through the provisions of the Town and Country Planning legislation and the permitted reserve will have been depleted to a Long Lane (west of Long Lane) (Sg) Stocker’s Lake (Sg) School (Sg) Montague Road (Marsh Side) (Sg) till. Extensive glacial sand and gravel deposits are present in the area where they lie on the eroded surface of the White Chalk Subgroup. More patchily distributed deposits are located further to greater or lesser extent. Current planning status is not qualified on the map but is available in the underlying database. Land off Hive East of Cemetry on Montague the east in the Standon area where the deposits thin and occur with the glaciofluvial derived Kesgrave Formation. National nature conservation designations Springwell Lock (Sg) Harefield Road (Sg) Road (Cl) Road (Marsh Side) (Sg) South of Pickets Lock (Sg) Harefield Lime Quarry (Springwell Lock) (Ch, Fi) (SSSIs and NNRs) Springwell Lane (Sg) The deposits comprise approximately equal quantities of sand and gravel (48% and 42% respectively), with the remainder fines. Cobbles occur sporadically throughout the deposit and the gravel is Contact addresses: Montague Road, First Avenue (Sg) Lynsters Lake (Ware Cottage) (Sg) composed of approximately equal proportions of fine and coarse grades. In the sand fraction, medium-grained sand predominates over approximately equal proportions of fine and coarse grade material.

International nature conservation designations The clasts are predominantly angular and nodular flint with minor angular and rounded quartzite pebbles from the Triassic Kidderminster Formation (formerly Bunter Pebble Beds) of the Midlands and minor Hertfordshire County Council, Environment Department, County Hall, Hertford SG13 8DN, Tel: 01992 556265, Fax: 01992 556202, Web Weybreads Pit (Filocol Works) (Sg) vein-quartz pebbles. (SACs, SPAs and Ramsar sites) page: www.hertscc.gov.uk Lynsters Lake (Lynsters Farm) (Sg)

Lynsters Lake (Coppermill Lane) (Sg) Lynsters Lake (Pynesfield Farm) (Sg) River terrace deposits Barnet London Borough, Environmental Services Department, Barnet House, 1255 High Road, Whetstone, London N20 0EJ, Tel: 020 Troy Mill (Sg) Area of Outstanding Natural Beauty (AONB): Chilterns (part) 8359 2000, Fax: 020 8359 4616, Web page: www.barnet.gov.uk Church Hill (Sg) Post-Anglian river terrace deposits occur at several levels in most of the major valleys in the county flanking the present floodplain. They are generally dry in their upper parts and saturated at their bases.

90 These deposits comprise sequences of sands and gravels typically 3-6 m in thickness with sheet-like geometry and sub-horizontal upper surfaces. Compositionally, the main component of the gravels is 90 Enfield London Borough, Environmental Services Department, PO Box 53, Civic Centre, Silver Street, Enfield EN1 3XE, Tel: 020 8379 Broadwater Farm (Sg) flint, although they may locally contain a small percentage of quartz and quartzite reworked from the fluvioglacial sand and gravel. Scheduled Monument 3811, Web page: www.enfield.gov.uk Schematic map illustrating approximate distribution and composition of

Harefield (Sg) NE of Harvil Road (Sg) sand and gravel deposits in Hertfordshire and the NW London boroughs In south Hertfordshire, Pre-Anglian tributaries flowing northwards into the early Thames laid down spreads of fluvial deposits on higher ground. However, since these gravels contain fewer non-flint pebbles Harrow London Borough, Environment, Planning and Transportation Division, PO Box 37, Civic Centre, Harrow HA1 2UY, Tel: 020 8863 Harefield (North of Moorhall Road 1) (Sg) Denham (Sg) than the coeval glaciofluvial sand and gravel they have been classified as river terrace deposits with which they are compositionally similar. 5611, Fax: 020 8424 1551, Web page: www.harrow.gov.uk

ADMINISTRATIVE AREAS Broadwater Lake (Sg) Dews Farm (Sg) Sub-alluvial gravel Hillingdon London Borough, Planning Services, Civic Centre, Uxbridge UB8 1UW, Tel: 01895 250111, Fax: 01895 556202, Web page: South of Moorhall Road (Sg) Broadwater Lake (Sg) www.hillingdon.gov.uk Region Harefield Halt (Sg) Sub-alluvial gravels are encountered beneath the alluvium of the major valleys throughout the county. They were mainly laid down during periods of deep downcutting during the last major glaciation

(Devensian) when sea-levels fell to at least 100 m below the present level. The subsequent rise in sea-level enabled silting up of these river channels producing the overlying alluvial deposits (silty clays, South Harefield Halt (Sg) Fray’s Farm Meadow (Sg) Mineral Planning Authority peat). The gravels rest on an irregular channelled surface and are thus of very variable thickness, locally 5-10 m of deposits are present but they are commonly thinner. These deposits are generally similar

Fray’s Meadow (Sg) in composition to river terrace gravels, however, they are saturated and would require wet working if they were exploited. Deposits of sub-alluvial gravels occur within the valley of the rivers Mimram, Ver

and Colne, in the and Hemel Hempstead areas. Gravel deposits of the Colne and Ver valleys have been extensively worked in the past and resources hvae been exhausted in many locations. District Topography reproduced from the OS map by British Geological Survey with the permission of Ordnance Survey on behalf of The

Controller of Her Majesty's Stationery Office, © Crown copyright. All rights reserved. Unauthorised reproduction infringes Crown copyright and may lead to prosecution or civil proceedings. Licence number: GD272191/2003. Production of sand and gravel (in Hertfordshire only), 1979 - 2001

Total permitted reserves = 10,191,000 tonnes (as at 01.01.02) Administrative boundaries are reproduced with permission from Ordnance Survey Boundary Line. Licence number GD272671/2003. Thousand tonnes Aims and Limitations Digital SSSI, NNR, SPA, SAC and Ramsar boundaries © English Nature 2003. Stockley Road (Sg, Cl) 4000 4000 Contact address: Trident Site (Horton Road) (Sg, Cl) Colham Northolt Brickworks (Cl) The purpose of the maps in this series is to show the broad distribution of those mineral resources which may be of current or potential English Nature, Northminster House, Northminster, Peterborough, PE1 1UA, Tel: 01733 455000, Fax: 01733 455103, Web page: Green (Sg) economic interest and to relate these to selected nationally-recognised planning designations. The maps are intended to assist in the www.english-nature.org.uk North of Packet Boat Lane (Sg) consideration and preparation of development plan policies in respect of mineral extraction and the protection of important mineral East of Chapel West Dawley Yeading Brickworks (Cl) resources against sterilisation. They bring together a wide range of information, much of which is scattered and not always available in a South of Packet Boat Lane (Sg) Lane (Sg) Positions of Scheduled Monuments at 15th August 2001 as supplied by English Heritage. Road (Sg) Recreation Ground (Bothwell Common Road) (Cl) 3000 3000 convenient form. The majority of monuments are plotted using a centred NGR symbol. Consequently the actual area and/or length of a monument North of Trout Lane (Sg) Brookside Brickworks (Cl Sg) Predominantly exposed quartzose deposits protected by the legal constraints of scheduling cannot be represented here. Monuments scheduled since that date are not accounted The Lizards (Trout Road) (Sg) The maps have been produced by collation and interpretation of mineral resource data principally held by the British Geological Survey. for. © Copyright English Heritage. North of Grand Union Canal (Sg, Cl) Information on the extent of mineral planning permissions has been obtained from the relevant Mineral Planning Authority (MPA). Some South of Trout Lane (Sg) 80 Contact address: Thorney West Drayton (CR) Predominantly concealed quartzose deposits 80 of these permissions may have lapsed or expired. The status of individual areas can be ascertained from the appropriate MPA. Location English Heritage, 23 Savile Row, London, WS1 2ET, Tel: 020 7973 3132, Web page: www.english-heritage.org.uk Sipson Lane (Sg) West Mill (Sg) 2000 2000 information on national planning designations has been obtained from the appropriate statutory body (Countryside Agency, English Harmondsworth Lane (Holloway Lane) (Sg) Drayton (Sg) Hayes (CR) Scattered more flint-rich deposits Nature and English Heritage). For further information the relevant body should be contacted. Digital AONB boundaries © Countryside Commission 1986 (now Countryside Agency). North of Moor Lane (Sg) Thorney Mill (West Drayton) (CR) Frogsditch Farm (Sg) (Northern tributaries of Proto-Thames) Contact address: Egglesey Farm (Sg) The mineral resource data presented are based on the best available information, but are not comprehensive and their quality is variable. Harlington (Sg) Countryside Agency, John Dower House, Crescent Place, Cheltenham, Gloucestershire, GL50 3RA, Tel: 01242 521381, Fax: 01242 South of Moor Lane (Sg) The inferred boundaries shown are, therefore, approximate. Mineral resources defined on the map delineate areas within which 584270, Web page: www.countryside.gov.uk Cranford Lane (North & South Cranford Lane) (Sg) Scattered more fint-rich deposits Moor Lane (Sg) (Southern tributaries of Proto-Thames) 1000 1000 potentially workable minerals may occur. These areas are not of uniform potential and also take no account of planning constraints that Colnbrook (Sg) Imperial College Playing Fields (North) (Sg) may limit their working. The economic potential of specific sites can only be proved by a detailed evaluation programme. Such an Published for the Office of the Deputy Prime Minister © Queen's Printer and Controller of Her Majesty's Stationery Office 2003. North of Colnbrook By-pass (Sg) Wallgarden Farm (Sg) Approximate northern limit of glaciofluvial deposits investigation is an essential precursor to submitting a planning application for mineral working. Extensive areas are shown as having no (Kesgraves and equivalent) mineral resource potential, but some isolated mineral workings may occur in these areas. The presence of these operations generally This publication (excluding logos) may be reproduced free of charge in any format or medium for research, private study or circulation North of Bath Road (Sg) Cranford Lane South (North & South Cranford Lane) (Sg) Approximate southern limit of glaciofluvial deposits reflect very local or specific situations. within an organisation. This is subject to it being reproduced accurately and not used in a misleading context. The material must be Horton Road (Poyle) (Sg) Terminal 5 Imperial College Playing Fields (South) (Sg) (Kesgraves and equivalent) acknowledged as Crown Copyright and the title of the publication specified. 0 0 South of Bath Lane (Poyle) (Sg) (Heathrow) (Sg) 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 The maps are intended for general consideration of mineral issues and not as a source of detailed information on specific sites. The Robbs Nurseries (Sg) Approximate limit of generally thick glacial deposits on glaciofluvial Harmondsworth Lane (South side) (Sg) and river terrace deposits Source: Annual Minerals Raised Inquiry, Office for National Statistics maps should not be used to determine individual planning applications or in taking other decisions on the acquisition or use of a Applications for reproduction should be made in writing to: The Copyright Unit, Her Majesty's Stationery Office, St Clements House, Horton Road (Upper Mill, Spout Arch (Sg) particular piece of land, although they may give useful background information which sets a specific proposal within context. 1-16 Colgate, Norwich NR3 1BQ. Fax 01603 723000 or e-mail: [email protected] Stanwell Upper Mill) (Sg)

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