Brooksby Quarry Opens For Business
Lafarge Aggregates expand their operations in Leicestershire
The most recent quarrying operation to open in Leicestershire came on stream in January this year. Lafarge Aggregates’ Brooksby Quarry, a greenfield site located just north of the village of Rearsby on the A607 Melton Road at Brooksby, near Melton Mowbray, is situated on agricultural land owned by Brooksby Melton College, a further education establishment specializing in land-based subjects. The site was originally identified as a preferred area for the release of sand and gravel in the Leicestershire Minerals Plan adopted in 1995, to help meet the county’s demand for some 1.3 million tonnes of sand and gravel per annum.
Five years later, in June 2000, Lafarge Aggregates applied for planning permission to develop the site. The scheme was approved by Leicestershire County Council in April 2002 and planning permission was granted in September 2003, subject to a number of conditions. These included: a restriction on output prior to completion of the Rearsby bypass; a suitable scheme of ameliorative measures, including appropriate stand-offs and landscaping; retention of a public bridleway (part of the Midshires Way) which cuts across part of the site; appropriate archaeological investigations; and progressive restoration to a combination of agricultural land and water bodies.
The extraction site itself is largely out of sight from local access points and is reached via a dedicated new access road from the A607. The quarry has reserves of 3.14 million tonnes of sand and gravel, which will be worked at a rate of up to 300,000 tonnes per annum during a 15-year scheme that runs until 2021. A further 1.6 million tonnes of sand and gravel have also been identified immediately south of the currently consented mineral extraction area, which could provide a further six years’ supply subject to approval by the county council.
Preparatory work on the greenfield site began in April 2006, with a view to the processing plant being fully operational by July and the quarry opening for sales in August. However, the discovery of a number of significant archaeological remains, including five prehistoric burnt burial mounds, resulted in a delay to the planned start date, with sales finally commencing in January 2007. Much of the archaeology unearthed at the site is situated in the vicinity of the processing plant, where it has been recorded, preserved in situ and reburied. The remainder of the site will be subject to a watching brief as extraction progresses.
In addition, the sands and gravels being extracted at Brooksby are of interest to geoarchaeologists. Part of the Bagington and earlier Brooksby formations, they consist of river deposits that were laid down prior to the Anglian glaciation around 500,000 years ago. Borehole surveys have suggested the presence of organic remains that could be of national significance, and the scheme of working includes provision for a programme of recording and sampling from the face as quarrying progresses.
The raw material itself comprises around 60% sand and 40% gravel, with very little oversize material (+40mm), although these proportions are expected to vary as extraction advances across the site. The deposit also varies in thickness across the site, ranging from 2–3m in some places to 12–15m in others. The material is being worked dry by an excavator and dumptruck combination on a phased campaign basis, with the as-raised material being stockpiled adjacent to the processing plant. To date, some 40,000 tonnes have been extracted, completing the first phase out of a total of 11. The resulting void is currently fulfilling both settlement and clean-water requirements at the site.
Rather than investing in a fixed processing plant from the outset, Lafarge opted for a fully mobile sand and gravel washing and screening plant supplied on a contract basis by Staffordshire-based Aggregate Processing Solutions Ltd. Operating on a one-year trial basis, this option has worked well to date, with the plant comfortably meeting the 200 tonnes/h throughput required to achieve the quantity, quality and consistency of product that Lafarge require.
Designed to produce a fine building sand, a coarser concrete sand and 10mm, 20mm and 40mm gravel fractions, the low-level plant comprises four TEREX Finlay machines – a 390 Hydrascreen feed unit, an MP300 washing/screening plant, a TC15 Sandmaster twin-sand plant and a 683 Supertrak three-way-split screener – and utilizes 1,300 gal/min of fresh water drawn from the lagoon.
Fed by wheel loader from the adjacent raw material stockpile, the 390 Hydrascreen with its adjustable tipping grid, 7m3 feed hopper and 1m wide main conveyor is used (without its usual twin-deck screenbox attachment) to feed the as-raised material to the MP-300 unit. This relatively new addition to the TEREX Finlay range comprises a 16ft x 6ft Cedarapids horizontal screen with spraybars, Finlay 206 log-washer, 650mm wide oversize conveyor, 5ft x 4ft dewatering screen and 800mm wide main conveyor, all mounted on a road-mobile chassis equipped with jack-up legs.
The MP-300 washes and scrubs the incoming feed to produce a clean –5mm sand fraction, a washed –40mm +5mm gravel fraction and a +40mm oversize fraction. The minimal amount of oversize contained within the feed, which is insufficient to warrant a permanent crushing stage, is discharged to a ground stockpile at the side of the MP-300, while the sand fraction is fed to the TC15 Sandmaster unit. This self-contained portable unit utilizes two Linapump centrifugal slurry pumps (15kW and 30kW), two vertically mounted hydrocyclones (18in and 24in), a split collection tank and a dewatering screen with central divider to produce up to 120 tonnes/h of sharp and soft sands. Meanwhile, the gravel fraction is discharged into the 683 Supertrak, which uses its 12ft x 5ft twin-deck screenbox and three discharge conveyors to produce the required gravel fractions.
The plant’s permitted working hours are from 7am to 7pm during the week and from 7am to 1pm on Saturdays, although weekday operations normally finish at around 4.30pm and Saturday mornings are generally reserved for maintenance activities. Excluding temporary contractors, the site is run by three Lafarge personnel – the quarry manager, together with a weighbridge clerk and wheel loader operator.
Two new surface-mounted steel bridge decks, supplied by New City Scales, cater for the weighing of incoming/outgoing vehicles, which are required to follow a one-way system around the yard area. Vehicles leaving the quarry are required to cover their loads at the sheeting platform and, when site conditions dictate, pass through a Wheelwash washing system before joining the public highway. The two weighbridges are located on each side of a secure Surespace administration and weighbridge office unit supplied by Thurston Building Systems, who also provided a second Surespace unit to accommodate the staff canteen/mess facilities.
With considerable investment in new building developments taking place in Leicester, Melton Mowbray and the surrounding area, Brooksby Quarry is already supplying much-needed materials to a wide range of customers. Back in January, the first load to leave the site went to Jelson Homes for their landmark Hallam Fields housing development in Leicester. Other customers include Syston-based masonry unit manufacturers Interfuse, FG Construction, Truman Contractors, as well as many other smaller local builders and builders’ merchants. In addition, the site supplies materials to one internal customer – Lafarge’s Barnstone Works, a former cement facility located a few miles north of Brooksby, which has recently been converted to a blending and packing operation.
Despite the gradual increase in lorry traffic, which is expected to peak at around 125 loads per day at full production, Lafarge are working hard to ensure the quarry has minimal impact on the local community. New hedgerows have already been planted, the Midshires Way has been preserved, the locally popular Rearsby brook is being carefully maintained, and the company organizes regular meetings and site visits with the Brooksby Quarry liaison committee to keep stakeholders informed of progress and future developments. In addition, the quarry hosts around 20–30 visits a year for Brooksby Melton College students on relevant land-based courses.
Acknowledgement
The editor wishes to thank Lafarge Aggregates for permission to visit the site and, in particular, Adrian Bunyard, quarry manager, for his assistance in preparing this article.