UK SCRAPERS
Projects
Client. Professional Group Ltd
Site Location Redrow Homes, Woodford Aerodrome, Stockport
This former airfield site is to become a new 'garden village' and we were contracted to undertake the earthworks on phase two of the project. This involved stripping and stockpiling approximately 54000 m2 of predominantly wet topsoil's prior to birds nesting followed by a cut to fill and compact of around 800000 CuM of subsoil's. Areas were trimmed to tolerance using GPS achieving high accuracy and handed over in line with site program progression.
Our operations were completed over a two month period.
Client JN Bentley Ltd
Site location WRG Group, Winterton Landfill Site, Scunthorpe
This active landfill site required additional tipping space for domestic waste which meant the construction of a new cell and also an extension of the bunds and cell walls surrounding a hazardous waste cell. Also included were temporary capping works for the finished portion of a sulphate cell.
The sulphate cell capping was used by JN Bently’s site agent, Sean Wilby to evaluate the scrapers performance compared to conventional methods because at this stage pull type scrapers were untried within the company. The objective was to cart approximately 5500 cubic metres of clay from a stockpile to form a 450mm thick temporary capping to the sulphate waste with a 1.5 metre bund along the edge of the active section to avoid dust and rainfall hazards. After initially grading the waste within the cap area, the clay was placed to specification using our Tractor pulling one 19 Cu Y scraper in 20 working hours with only a self propelled roller required to seal the clay following placement. Site agent Sean Wilby was very impressed with both the efficiency and associated cost savings demonstrated during this trial and immediately put the scraper to work on the remainder of the contracts detailed below.
Excavated spoil from the domestic waste cell (DWC) construction was used partly to form the bund extension for the hazardous waste cell (HWC) and after completing the temporary capping to the sulphate cell, our Tractor / scraper was involved in trimming the new DWC floor to level removing the bulk prior to a laser dozer fine trimming to finished level. Once completed we began to place the clay for the cell liner using three tractors with 19 cubic yard scrapers. The clay had been previously stockpiled and was located approximately 150 metres from the DWC area. Specification required it to be placed in four 250mm layers and tested for condition and compaction at various places on each layer using an NDG (nuclear density gauge) to ensure impermeability to liquid.
During the scraper loading process any lumps contained in the stockpile were broken down which conditioned the clay sufficiently to allow direct placement in the cell. Cycle times were around five minutes with the scrapers grading each layer to within the tolerances required. It was also noted at this stage that the layout of the four rear wheels on each scraper compacted the clay to NDG specification although a padfoot roller was still used to ensure even compaction and keying between layers. This operation was completed during a period of foul weather and despite this the scrapers were able to return to work much faster than using conventional methods because of their ability to grade haul roads, stockpiles and fill areas and also to clean up following rain.
The HWC bund required spoil sourced from various site stockpiles to be engineered in 250mm layers. Once completed to the required finished levels, a clay liner was placed in 250mm layers on the inside, 45 degree face of the bund using a bench system at one scraper width, (3M), to facilitate compaction which was then trimmed to the correct depth using a backhoe.
Throughout these contracts the scrapers were noted to be very fuel efficient, safer due to fewer operatives on site and demonstrated a large cost per cubic metre saving compared to conventional earthworks methods because of minimal plant usage.
JN Bentley’s Sean Wilby commented “Watching the scrapers placing and accurately trimming clay was a revelation, straightening up haul roads while returning to the stockpile coupled with obvious fuel/labour savings, the modern scraper offers versatility that is hard to ignore.”
Sean can be contacted through JN Bentley’s website at http://www.jnbentley.co.uk/
Client. Hewlett Civil Engineering Ltd
Site Location Staithgate Lane, Bradford
Here the objective was to excavate and cart approximately 45000 cubic metres of colliery shale, clays and mudstones to a large fill area (300M haul) and smaller reinforced fill areas located underneath overhead power cables (450M haul).
The large fill area required 25000 cubic metres deposited in 200mm layers for compaction and was completed to finished levels in 4.5 days working ten hour shifts using a tractor tandem pulling two 18CuY scrapers and tractor pulling one 19 CuY scraper along with a self propelled pad foot roller.
The smaller fill areas required geotextile mesh at 500mm layers for soil reinforcement and to place 20000 cubic metres of fill to finished levels below the overhead power cables. Height restrictions were in place which prevented the use of ADT’s so using the above plant and also a small backhoe to trap the tensar on each layer, it was completed in seven 10 hour shifts.
Average fuel usage recorded per tractor was an economical 28 litres per hour with minimal site traffic and associated site hazards. Cut and fill areas were at all times safe from falling objects, reversing vehicles and the usual support equipment required to do such an operation These areas were also constantly sealed against the unpredictable British weather by cutting and filling to avoid the possibility of standing water in the event of a downpour, although on this occasion we managed complete all our works without rain.