Contract Details:

• Employer - Rolls Royce Submarines (Project Manager - Mr. Nick Skinner)
• Value - £1,600,000
• Duration - 26 weeks
• Engineer - SLR Consulting
• Form of Contract and Method of Measurement: NEC Option D, CESMM3

During the summer of 2004 Moulding Contracts Limited were awarded the contract by Rolls-Royce Marine Power to develop and restore their landfill facility at Hilts Quarry in Crich, Derbyshire. The works comprised of three key elements: quarry face stabilisation; installation of a composite capping system and the placement of restoration soils. Hilts quarry had been used by Rolls-Royce for the disposal of low-level radioactive waste (LLRW) contained within foundry sand since 1966. The quarry void had only been partially backfilled with waste, leaving a near vertical face which required remedial works to ensure
long term stability.

The site was extremely sensitive due to ecological issues; the close proximity of private residences; health and safety; and the access and the nature of the waste stored on the site. Subsequently careful consideration of working methods for each work element was necessary setting out how the works were to be constructed to meet not only the Specification and health & safety regulations, but also other issues specific to the site setting and ecology. A method statement for each operation took account of the necessary measures in order to mitigate any disturbance caused by the works to local residents and the flora and
fauna on site.

The scope of the works comprised
of the following:

• Clearance of vegetation
• Construction of artificial badger setts
• Heavy and light scaling of the quarry faces
• Installation of rock bolts and dowels to the quarry face
• Application of steel mesh to the quarry face
• Application of shotcrete to the quarry face
• Excavation and filling of the quarry floor to form new formation
• Excavation to form ephemeral soakaway and surface water feature
• Installation of Geosynthetic Clay Liner
• Installation of VFPE geomembrane liner
• Installation of geotextile protector
• Installation of restoration soils
• Construction of surface water
drainage network

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Contract Details:

• Employer - Viridor Waste Management Limited
• Value - £1,100,000
• Duration - 25 weeks
• Engineer - Wardell Armstrong
• Form of Contract and Method of Measurement: ICE 7th Edition, CESMM3

During the summer of 2003 Moulding Contracts Limited were awarded the contract to develop part of the former Erin Opencast Colliery into a new landfill cell for the waste management operator, Viridor Waste Management Limited. The Works were constructed within an existing open excavation up to 40m deep covering an area of some 40 hectares
(known as the Erin void).

The local ground conditions comprised of materials from the previous opencast excavation operations (re-worked coal measures), materials imported as part of the reclamation of the former Ireland Colliery (essentially colliery spoil and slurry) and materials imported from Markham Colliery (colliery spoil and slurry) deposited in three lagoons within the works area.

Prior to commencement of cell construction the works area had to be cleared of the former colliery works contamination stored within these lagoons and their surrounding areas (colliery spoil, slurry and contaminated water) by two methods comprised of excavation and removal aided by a chemical flocculent treatment process. The removed materials were transferred to replacement settlement lagoons situated outside of the works area.

The scope of the works comprised
of the following:

Cell Works
• Site clearance and contamination removal as described overleaf
• Excavation from borrow pit and deposition in cell to new formation levels
• Construction of 1m thick engineered
mineral liner
• Construction of engineered separation bunds
• Installation of 2.5mm thick HDPE
geomembrane liner
• Installation of geotextile protection layer
• Placement of 300mm thick stone drainage blanket layer over protective geotextile
• Construction of leachate drains, monitoring points and leachate collection chambers
• Construction of surface water intercepting
ditch network
• Slope stabilisation treatment of upper cell levels utilising stone filled trenches and installation of raking drains connected into the new surface water drainage network

Capping Works
• Preparation of area to be capped, placement of 300mm thick regulating layer
• Installation of LLDPE flexible membrane liner over regulating layer
• Installation of protective geotextile with 500mm thick capping protective layer
over geomembrane
• Landscaping and grass seeding of
capped area

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Contract Details:

• Employer - Premier Waste Management Ltd
• Value - £6,000,000 (3 year Framework Contract, £2m per annum)
• Engineer - Wardell Armstrong

During the spring of 2003 Moulding Contracts Limited were awarded the contract to develop a former sand and gravel quarry into a new landfill facility for the waste management operator, Premier Waste Management Limited. The project had two objectives, firstly, the creation of a large landfill cell and secondly, construction of new office facilities and associated infrastructure.

The construction of the cell composite liner comprised of the following:

• Low permeability clay liner, imported,
0.5m thick
• Low permeability geosynthetic clay liner
• HDPE geomembrane (2mm) over cell floor and side slopes
• Geotextile protection layer over geomembrane
• 500mm thick granular leachate drainage layer, HDPE spine drains, leachate abstraction wells and monitoring shafts

The new office complex and weighbridge facility comprised of the following:

• New site entrance and weighbridge
approach road.
• Two new weighbridges with office and store
• Civic amenity disposal area
• Wheelwash and settlement tank
• Reception area, site offices, visitor and staff parking area
• Foul and surface water drainage
• Electrical sub-station
• Cell approach road and access ramp

In all, some 1.5km of palisade fencing was erected around the office / weighbridge complex in addition to the top of the new cell boundary. In total, approximately 4000m2 of reinforced concrete pavement was laid to the approach roads and car parking areas.

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Contract Details:

• Employer - County Environmental Limited
• Value - £2,800,000
• Duration - 30 weeks
• Engineer - Atkins
• Form of Contract and Method of Measurement: - NEC Option D, CESMM3.

During the summer of 2004 Moulding Contracts Limited were awarded the contract to develop part of the former United Mines Tin Mine Workings for the waste management operator, County Environmental Limited. The contract required primarily for the construction of a new landfill cell formed within the existing rockhead after first investigating (geophysical mapping survey and borehole investigation) and then treating & capping six existing mine shafts within the cell footprint in addition to further capping works to a nearby landfill . The contract also required the construction of associated infrastructure forming part of the new development comprised of a leachate treatment plant including a 1.2km long paved single carriageway service road together with associated drainage and 800m length security fence.

The cell works comprised of 350,000m3 of rock excavation into the existing rockhead (Mylor Slate) in order to provide the required formation levels for the new landfill cell. The excavated materials were hauled to a separate processing area where they were screened and batched for a secondary bentonite enrichment production process. In total, some 25,000m3 of bentonite enriched soils (BES) were processed and hauled back into the cell to be used as part of the composite lining system. The remaining materials were processed into other materials such as support soils to be used within the cell in addition to the capping area.

The composite cell lining system comprised of the following:

• 650mm subbase attenuation layer - Support Soils (S/S) 50,000m3
• 500mm BES layer (25,000m3)
• 2mm HDPE geomembrane (45,000m2)
• Geotextile (45,000m2)
• 300mm drainage blanket layer
• Leachate drainage system

The capping works comprised of the following:

• 300mm regulating layer made up from processed support soils
• 1mm LLDPE geomembrane (11,000m2)
• 550mm protection layer made up from processed support soils
• Subsoil layer
• Topsoil layer

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Contract Details:

• Employer - Biffa Waste Services
• Value - £1,200,000
• Duration - 24 weeks
• Engineer - SLR Consulting Limited
• Form of Contract and Method of Measurement: - ICE 7th Edition, CESMM3.

During the summer of 2003 Moulding Contracts Limited were awarded the contract to restore a 62 hectare area of land adjacent to the Client's active landfill containment facility. The contract called for the creation of a wetland habitat in the form of four lakes of various size and shape interlinked by a system of ditches with valve controlled headworks. Landscaping works included major re-profiling of existing ground contours by the formation of a 500m long bund, in order to screen the active landfill from nearby residential areas.

The earthworks involved 500,000m3 of excavation and filling in order to achieve the required restoration contours.

Additional works involved the construction of a 1.5km hardcore maintenance track around the site perimeter together with the erection of 2.5km of stock proof fencing and 1.4km of chain link security fencing. The four lakes were connected by a system of open ditches and outfalls with the inclusion of concrete spillways and sluice gates with valve controlled headwalls. Moulding Contracts Limited constructed a 600m flexible paved bituminous road in order to provide access to the restored area.

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