STONEHENGE FARM QUARRY DUST MONITORING SCHEME for: Hanson UK. August 2013

Transcription

1 Contaminated Land Air Quality Environmental Audit Partnership No: OC STONEHENGE FARM QUARRY for: Hanson UK August 2013 R1708-R02-v2 Smith Grant LLP, Station House, Station Road, Ruabon, Wrexham, LL14 6DL tel: fax: web: Members: A F Smith (Chairman), K E Hawkins, B J Thomas

2 1 DOCUMENT CONTROL SHEET Report Title: Client: Stonehenge Farm Quarry Dust Monitoring Scheme Hanson UK Report Reference Number: R1708-R02 Report Status: final Version: v2 Report Date: August 2013 For: Smith Grant LLP Author Name Position Signature Date pp L Dreiling BSc Consultant 22nd August AIEMA MIEnvSci 2013 MIAQM Checked A F Smith BSc PhD MCIWM SiLC Member 22nd August 2013 Document Revision Record: Version Report Status Date Details of Revision v1 draft 09/08/13 for client comment v2 final 22/08/13 minor edits/clarification

3 2 Contents 1 Introduction 2 Monitoring Rationale 3 Monitoring Methodology 4 Reporting and Review Drawing D02 Dust Monitoring Positions

4 3 1 Introduction 1.1 Hanson UK have been granted permission for the extraction of sand and gravel and associated processing, silt ponds, conveyors and ancillary works at Stonehenge Farm, Northmoor, Oxfordshire. 1.2 The operations will be governed by planning conditions which have been determined by Oxfordshire County Council (OCC), including the following condition in respect of dust management: 30 No development shall take place until a scheme of measures for the suppression of dust, has been submitted to and approved in writing by the Minerals Planning Authority. The scheme shall include: a) The suppression of dust caused by the moving and storage of soil and overburden, stone and other materials within the site; b) Dust suppression on haul roads, including speed limits The approved scheme shall be implemented and complied with at all times. 1.3 The operations will also be subject to other conditions which are relevant to dust emissions, including: 11 maintenance and cleaning of site access roads and vehicles, 12 sheeting of loaded vehicles. 1.4 Hanson UK instructed Smith Grant LLP (SGP) to prepare a dust management scheme in respect of condition 30. This was prepared and submitted to OCC who subsequently requested additional dust monitoring to accompany the scheme. This report describes the rationale behind the proposed monitoring scheme, the methodology to be used, reporting and review arrangements. 1.5 The dust monitoring scheme will be subject to regular review to ensure its continuing effectiveness. 2 Monitoring Rationale 2.1 Sources and Receptors The planned extraction area and mineral processing / storage areas are separated by a 1.5 km conveyor to transport sand and gravel in wet or damp condition for processing and loading to road haulage. The conveyor is not considered likely to be a significant source of airborne

5 4 dust, and largely follows a route through open farmland. The process and stock storage area is a long-established facility surrounded by farmland and flooded old gravel workings, and are remote from dust-sensitive receptors. This leaves the extraction area as a potential source of fugitive dust The site will be restored using topsoil and subsoil stripped from the site prior to the commencement of extraction. The soils will be placed in peripheral storage bunds or placed directly into areas ready for restoration. There will be no import of materials for restoration purposes The site will be worked in 6 phases. Phases 1, 3 and 5 will be worked wet and phases 2, 4 and 6 dewatered and dry worked. Wet working will utilise a 360 excavator to dig the mineral and to form a wet stockpile. A wheeled loader will transport the drained material to an electric powered conveyor. Dry working will be undertaken using a loading shovel to dig the material and load it onto the conveyor. Dewatering will take place in phases 2, 4 and 6 prior to extraction. The pumped water will be discharged to a settling lagoon within the phase 1 area or into a series of recharge ditches used to maintain groundwater levels within the surrounding land Phases 2 and 3 of the extraction area lie to the immediate south and west respectively of residential properties within the Park Farm settlement, off Standlake Road. Further residential properties lie to the north and west of Phase 3 and Standlake Road, including Gaunt Mill and Standlake Village. Southwest of Phase 4 is Newbridge Mill Cottage, whilst Stonehenge Farm lies to the southeast. Phases 1, 5 and 6 are relatively isolated from potential receptors, with Northmoor Village lying about 1km northeast of phase Much of the quarry site is surrounded by intensive arable farming which will itself be a source of dust from soils and crop processing at certain times of year. 2.2 Meteorological Conditions The annual wind rose for Brize Norton, 12 km west of the site, is provided below This shows the prevailing wind direction as from the southwest. On this basis, residential properties to the northeast of the extraction area are most likely to be at risk from dustblow, although other than Park Farm these are all at least 500m distant from the dry-worked phases.

6 5 WIND ROSE FOR BRIZE NORTON N.G.R: 4292E 2067N ALTITUDE: 82 metres a.m.s.l OBS. 2.1% CALM 0.0% VARIABLE 20% 10% 5% 0% > KNOTS SEASON: ANNUAL Period of data: Jan Dec Phasing The potential for dustblow towards receptors is considered to be low given the method of working and wet/damp nature of the deposits, perimeter screening and distance to most receptors (Park Farm excepted). Any risks to residential receptors outside the site will be greatest during short term operations such as soil stripping, bund formation and restoration, activities that need to be undertaken under dry soil conditions to preserve the soil structure Longer term mineral extraction in the dewatered deposits (phases 2, 4 and 6) may present limited potential for dust emissions, and of these, phase 2 is the most sensitive due to proximity to Park Farm. 2.4 Monitoring Requirement Due to the low level of dust risk assessed for the site, no baseline (pre-commencement) dust monitoring has been previously required or undertaken, and therefore it is assumed that typical rural deposition values 1 will prevail (10-50 mg m -2 day -1 ), although these may be substantially higher at times due to farming operations. The concern over dust emissions relates primarily to nuisance dust deposition causing soiling at the receptor location Fine particulate emissions are considered very unlikely to be a health issue due to the low source potential from wet or damp deposits, and due to high dispersion; experience from 1 Environmental Effects of Surface Mineral Workings, Waller Associates for DoE, 1991

7 6 similar sites has shown negligible changes in long or short term airborne concentrations of fine particulates and no potential for breaches of EU Limit Values set to protect human health The OCC request for dust monitoring will be implemented to coincide with the development works at the quarry, including site topsoil and overburden strip and bund formation, and conveyor installation. OCC has indicated that the monitoring should be undertaken at the site boundaries with respect to potential off-site migration of dust towards existing and future proposed residential development. The purpose of the dust monitoring will therefore be to: acquire information on background and site-generated dust sources, relate the date to dust observations or complaints, inform the regular review of effectiveness of dust controls, and, if necessary determine the requirement for any additional mitigation measures / modification to the dust management plan Outline guidance on dust monitoring methods is provided in Annex 1 "Dust" to MPS2 2. This notes that monitoring must be: specific to the type of dust that it is to detect (i.e. total deposition of undissolved particulates); quality assured / controlled, and information provided on calibration and servicing. 3 Monitoring Methodology 3.1 Visual Monitoring All operations with the potential to cause airborne dust emissions will be monitored by the Quarry Manager, or appointed person, at least once per day. This will include visual assessment of any impacts at a downwind location on the site boundary All observations and findings, including weather conditions, will be recorded in a log-book kept specifically for the purpose Should visible dust be generated, the Quarry Manager will act promptly to identify the source(s) and take the necessary corrective action. Each event, its' cause and the remedial action taken will be recorded in the site log-book If necessary, the Quarry Manager will instruct the suspension of any operation or process causing visible dust emissions until such time as the situation has been resolved. 2 Minerals Policy Statement 2, Controlling and Mitigating the Environmental Effects of Mineral Extraction in England, ODPM, 2005

8 Site staff will be instructed to inform the Quarry Manager whenever visible dust emissions are observed, or appear likely to occur, as a result of any operation or process. 3.2 Deposition Monitoring Dust monitoring, using combined deposition / direction gauges, will be carried out at three locations around the perimeter of the quarry, as shown on drawing no. -d01, to identify upwind and downwind total dust deposition and source direction information. The monitoring positions will be varied in accordance with the phasing of the quarry operation to ensure that the most sensitive boundary is monitored Monitoring equipment will comprise combined 'frisbee' type deposition gauges with collecting bottles and bird screens, and direction gauges. The direction gauges will comprise circular adhesive strips to provide 360 o directional data on sources, and an estimate of effective area coverage, a measure of soiling. The monitors will be mounted on level ground where possible, between the extraction area and perimeter, on stands a minimum of 1.5m above ground level, and a minimum of 3m from trees or hedges Samples will be collected over consecutive periods of 1 month by trained operators. Sampling equipment will be inspected during each visit and any evidence of damage or contamination will be noted and corrective actions taken as appropriate The analyses of dust samples will be carried out at UKAS-accredited laboratories and will include measurement of total and undissolved particulate (expressed as mg m -2 day -1 ), ph and daily effective area coverage (as %). The results will be reported to Hanson monthly. 3.3 Phasing Monitoring stations s1 and s3 are expected to remain in the positions shown throughout the site operations. Station s1 provides baseline data upwind of the site in the prevailing wind direction, but will also record any perimeter deposition from phase 4 towards Newbridge Mill Cottage under easterly or northeasterly winds. Station s3 will provide monitoring of the boundary with Park Farm throughout the operations, and particularly during conveyor loading in phases 1, 3 and 5, and dry working of phases 2, 4 and 6 during southerly or southeasterly winds Station s2 will be located at the northern side of phase 3 during the working of phases 1-3, to provide monitoring of the boundary with Standlake Road and properties towards Standlake Village. On development of phases 4-6 the gauge will be moved to the eastern end of phase 4 to provide coverage of properties to the east during westerly, northwesterly or northerly winds.

9 It is proposed to continue dust monitoring throughout the operational period, however the duration and frequency of monitoring will be subject to review on the basis of the results obtained. 4 Reporting and Review 4.1 General Requirements Dust results will be reported to OCC quarterly together with a short assessment. This will compare results to the expected rural background, and will note any particular weather conditions over the period that could have affected general dust conditions. The assessment will review the nature of site operations, dust observations and mitigation measures employed over the period An annual review will be held to assess the effectiveness of monitoring and opportunity for any relaxation or requirement for modification of the monitoring requirement based upon experience of the operational site and monitoring data over the preceding period.

10 Drawing

11 s2 3 1 s s2a s1 SM I T H G R A NT Environmental Consultancy LLP Smith Grant LLP, Station House Station Road, Ruabon, Wrexham, LL14 6DL Tel: Fax: consult@smithgrant.co.uk Project: STONEHENGE FARM, NORTHMOOR phase extraction area Drawing: dust monitoring station Drawn: phases 1-3, stations s1 (upwind), s2 and s3; phases 4-6, stations s1 (upwind), s2a and s3 Date: DUST MONITORING POSITIONS ld 09/08/2013 Job No: R1708 Checked: afs Scale: A3 Drg No: R1708-R02-D01