MARKHAM EMPLOYMENT GROWTH ZONE
SOILS MANAGEMENT STRATEGY FOR
PHASE Vb
Prepared - April 2014
Revised for submission – October 2015
Plant and Equipment
Plant to be used on site for the purpose of soil recovery and replacement will
include hydraulic excavators, articulated dump trucks, low ground pressure
bulldozers, and mobile screening units.
Soil Stripping and Replacement
Hydraulic back hoe (18 - 25 tonne)
Articulated dumptrucks (13 – 40 tonne capacity)
LGP dozer (180 - 200 HP)
All plant will comply with current legislative standards with regard to noise,
safety and emission standards. Each unit will be inspected before being
permitted to carry out any works and will undergo continuous assessment
under planned preventative maintenance procedures. Operators will be
accredited to CITB equivalent standard and will be trained and experienced in
the work called for under the proposed development.
Soil Recovery
Areas within Phase Vb consist of land in predominantly agricultural use, with
the exception of the central-eastern area which was previously occupied in
part by Seymour Colliery and Seymour Cottages until 1969 where the area
was used for purpose of coal stocking and in part where the land has been
previously utilised for rail sidings or for the deposition of bituminous product
arising from resurfacing of the adjacent M1 motorway or of colliery shale.
Significant areas of Phase Vb were until August 2014 in agricultural use and
exhibit between 200 and 350mm of cultivated topsoil depth. Site investigation
by both borehole and trial pit excavation show also isolated areas of topsoil,
with records indicating soil depths ranging from 0.05 to 0.7m although below
500mm depth the structure of the “soil” is rapidly lost and the substrate
changes to clays and mudstones. It is noted however that is previously
opencast areas between the M1 and the Clowne Branch Railway corridor little
evidence of subsoil has been found, the cultivated soil layer directly overlaying
the clay/mudstone substrate.
Field edges are likely to contain increased topsoil depth where windrows have
been created through annual cultivation of the soils.
Existing road verges have, in general around 200 - 250mm lower quality
topsoil depth with no identifiable subsoil layer beneath.
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In addition, there are several soil stockpiles on site, remnant from former soil
recovery operations at the time part of the site was cleared to allow coal
stocking operations.
In all, site investigation combined with current land use suggests that there is
significant soil resources on site which can to be carefully recovered for re-use
within the MEGZ site extents.
To ensure that the resource is carefully recovered and managed for re-use,
soils will be excavated by medium sized hydraulic back-hoe excavator and
hauled in 30 - 40 tonne capacity articulated or rigid dump-trucks for placement
either into temporary stockpiles or directly to final deposition location.
Every effort will be made to recover all soils within the existing agricultural and
road verge areas including soils from beneath existing hedge/fence lines.
Where necessary the soils will be screened to remove roots and or timber
products along with debris or any other man-made product to ensure a
product suitable for re-use. The quality of soils recovered and requiring
screening will be assessed prior to their replacement within the works or their
stockpiling for future use within the overall MEGZ site, with the exception of
soils lifted to allow construction of the temporary haul road across fields linking
the M1 over-bridge to the Markham Colliery North Tip site, and those in area
which is to be stripped and under-filled before restoration to agricultural use,
to the north of Development Plot 14, the soils from each of these sites to be
carefully segregated for storage and replacement within each specific site.
(Note: A separate detailed methodology has been negotiated with the tenant
farmer / occupier of the agricultural land to the north of plot 14 which is to be
returned to agricultural use once under-filled to assist screening of the plot.
This methodology dated 13 Feb 2015 is attached as Appendix 1 at the end of
this report)
Every effort will be made to recover the maximum amount of suitable subsoil
from within the site for reuse within the MEGZ site as a whole.
Topsoil and subsoil will be stored in separate stockpiles and materials
recovered from different soil interests will also be placed in individual
stockpiles to avoid any cross contamination.
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Soils Handling and Replacement
The general methods and plant employed in soils are as outlined above.
The work will only be carried out in suitable weather conditions. Soils will
only be placed in daylight hours. The topsoil will not be replaced in wet
weather or other such conditions which could be detrimental to the topsoil.
Only approved dump trucks and tracked dozers will be used for hauling and
spreading topsoil and plant movements on top-soiled areas shall be restricted
only to trafficking with low ground pressure dozer or with equipment use for
preparation, cultivation and seeding operations post soil replacement.
The laying of subsoil will be carried out in such a way as to minimise
trafficking and consequent panning and compaction of the surface and the
topsoil will also be laid uniformly to final contours in a single pass in such a
way as to further minimise trafficking and panning.
Where possible, as areas are restored to final levels, soils will be placed
directly to their final deposition location as they are recovered. All movement
of soils will be undertaken using best practice methods to ensure particle
damage is kept to a minimum.
The proposed areas for storage of topsoil and subsoil are shown on the
drawing no. 9033/1327.
Stockpiles will not exceed 4m in height for topsoil, and 6m in height for subsoil
and will have low gradient outer slopes. Soil stockpiles will be located so far
as possible to provide additional visual screening to the site operations but
with consideration also given to the need to avoid repeated re-handling.
Stockpiles will be located outside excavation areas or in areas where
restoration is completed where possible. Excess topsoil is anticipated which
will remain stockpiled on completion of earthworks and stockpiles which are to
remain in situ for longer than 12 months shall be seeded with a low
maintenance grass seed mix to deter the establishment of weeds. Spraying
will be used as a last resort to prevent vigorous weed growth.
With respect to the re-use / placement of soils, different process will apply to
each deposition site.
With respect to the North Tip (MEGZ Phase ll), it is noted that remediation
strategy for the existing colliery spoil tip remains outstanding but also hereby
advised that that the council is not currently in a position to submit a
remediation strategy for Phase ll at this time. Remediation work will therefore
be severely restricted and will be limited to the import and placement of a sub
and top soil overlay within two discrete unsoiled areas located on the north
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east flank of the tip extents and which are exhibiting sparse tree growth due to
‘acidic’ ground condition, these as identified on drawing 9033/1327. Existing
self set sparse tree cover will be cleared but there will be no re-profiling of the
flanks of the tip and no disturbance of the colliery discard forming the tip
slope.
With respect to the South Tip, material will be imported, spread and
compacted and profiled through tracking of vehicles to form the south tip
extension / screen mound shown on drawing 9033/1327, this to provide
screening of much of the proposed development within Plot 1 from Bolsover
Castle in accord with the original MEGZ consent.
Once grading and preparation of the North Tip and South Tip sites is complete
the exposed surfaces will be ripped/rooter with a wing tined ripper to ensure
removal of any pan within the top 600mm depth which would lead to restriction
on drainage through the substrate. At both sites, final landform will be
achieved through placement of a 900mm loose fill layer comprising a mix of
clay/mudstone and recovered sub-soils to provide a root zone for
establishment of future vegetative cover. Following rooting of the subsoil
surface, topsoil will be spread over prepared areas to a depth of 100mm.
The following volumes of materials are anticipated to require haulage to the
tips sites:
North Tip:
South Tip:
Soil / Fill type
58930m³
6500m³
69288m³
8000m³
Mixed subsoil / loose clay/mudstone fill
Topsoil
Batters to proposed future industrial plots and to future road verges: will be
finished through replacement of a 100mm depth of topsoil, this as previously
recovered from existing field areas or soil, stockpiles (Any greater topsoil
depth has been proven to fail on 1 in 3 side slopes during recent extended
periods of very wet weather).
After subsoil has been laid (where this is advised above) it will be rooted to
100mm beyond its full depth with a winged shank rooter to break any pan that
may have been created at the interface with the underlying material.
Similarly, the topsoil layer will be rooted to 100mm beyond its full depth once it
has been laid in order to break any pan that may have been created at the
interface with the underlying material.
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On completion of rooting of both the subsoil and topsoil the rooted material will
be cultivated with approved equipment at right angles to the rooting and then
the material will be stonepicked to remove all material which will not pass a
150mm/100mm diameter ring respectively, as a combined or sequential
operation.
The surface of the stonepicked subsoil will be left as a cultivated surface
unless levelling and firming by levelling sledge or agricultural scrubber or other
approved grading method is required. Before any subsequent spreading of
topsoil is carried out on firmed and levelled subsoil the surface of the subsoil
will be rough cultivated.
The surface of the stonepicked topsoil will also be left as a cultivated surface
which shall be grass seeded with an appropriate low growth / low
maintenance grass seed mix to provide protection against erosion whilst not
affording competition to any future tree planting scheme, exception being the
restored North Tip site where seed mix will be selected to allow for future
grazing and /or recovery as hay.
Calculation of exact quantities of likely topsoil recovers has been based upon
soil area and depth, however, it should be noted that variation in the depth of
agricultural soils may result in deficit of an excess of topsoil within the Phase
Vb site. Should there be a likely deficit during replacement of soils, topsoil
thickness will be reduced by up to 20mm on batter slopes during soil
replacement operations, however, should there be an excess of soils,
thickness will not be increased but excess soils will be carefully stored in
separate stockpiles within Phase Vb, and stockpiles retained for future use
within the MEGZ site during overall landscape works and landscape works
associated with future development of the plots within the site.
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Appendix 1
Proposed Method of Working, Agricultural Field – Stripping & Replacement of
Soils
Topsoil & Subsoil stripping
All soils to be stripped using a tracked 360 excavator equipped with a
toothless bucket to minimise mixing and contamination of the soils. Stripping
to commence at the South West boundary of the field, topsoil will be removed
carefully to the subsoil interface with the excavator positioned on the topsoil
horizon, the width of the panel to be stripped will be determined by the reach
of the excavator (circa 10m – 12m), the soil will be stripped from South to
North with the arisings placed into a small temporary bund directly to the East
and parallel to the stripped area. On completion of this initial panel, the
excavator will then be positioned on the subsoil horizon at the South end and
the exposed subsoil will be loaded directly in ADT’s travelling and loaded on
the overburden horizon, the subsoil will be hauled to a temporary stockpile
area outside the strip area (location to be agreed). On completion of this
subsoil panel strip the topsoil bund will be removed to a temporary stockpile
with the ADT’s loaded on the adjacent exposed overburden surface. Alternate
panels of topsoil & subsoil will then be removed heading to the Eastern
boundary, working as described above with the loading machine positioned
on the soils and the ADT’s only travelling on the overburden surface. Soils will
only be removed when in a dry and friable condition, stripping operations will
cease during any periods of persistent rain.
Temporary Stockpiles
To minimise compaction of the temporary stockpiles, soils will be tipped onto
the base of the storage area and then dozed into the required configuration
with a LGP dozer thus preventing compaction by the ADT’s, stockpiles will
have graded finish and left with a domed profile to prevent water ponding
The topsoil stockpile will be no greater than 4m in height, the subsoil stockpile
will be no greater than 6m in height.
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Bulk Filling Operation
Selected fill material will be placed to the required level using ADT’s, fill will be
placed in layers with the material blocked tipped, to minimise compaction each
loose tipped layer will be spread using a LGP dozer, ADT’s will be routed to
minimise compaction.
Replacement of Soils
On completion of the bulk filling operation the original stripped soils will be
replaced onto the agricultural field. The soils will be replaced using a strip
method. Prior to the placement of any soils the receptor area will be cross
ripped using a tracked dozer equipped with a multi shank ripper to a depth of
approximately 500mm – a strip of 15m wide will be ripped to receive the
subsoil, the subsoil will then be loose tipped onto the ripped area, with the
ADT’s reversing at right angles to the strip and with only the rear axle tyres
travelling onto the ripped area, the tipped subsoil will then be spread with a
LGP dozer to the required width and depth (approx. 12m and 0.3m). On
completion of a subsoil strip the area will be cross ripped to the depth of the
subsoil or slightly below into the overburden surface. Topsoil will then be
placed onto the strip of completed subsoil, this will be achieved by the ADT’s
reversing to the subsoil area at right angles to the direction of the strip and
tipping the topsoil directly onto the subsoil strip, to minimise compaction only
the rear axle tyres will reverse onto the subsoil layer, the tipped topsoil will
then be spread with a LGP dozer to the required width and depth. Progressing
in strips as described above the entire field area will be re-soiled. The
replaced topsoil area to be cross ripped to a depth of approximately 300mm
on completion.
Removal of soils from temporary storage areas
The soils will be removed from the storage heaps using a tracked excavator.
The excavator will be positioned on top of the heaps or will bench into the
heaps to achieve a suitable loading platform, the ADT’s will not travel onto the
storage heaps but will be positioned on the overburden base during the
loading operation. To prevent contamination with the bases of the storage
heaps the excavator will be equipped with a flat edge bucket.
A E Taylor
Fitzwise Ltd
13/02/15
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