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During the 1930s mechanized excavation began to replace some of the manual labour in the pits. Steam excavators on caterpillar tracks or road wheels began to be used to remove the top soil overburden. These machines were not energy efficient - they burnt a ton of coal a day and used 690 gallons of water - but their use meant that large amounts of sand could be uncovered quickly, to keep up with increased demand.

Ruston Bucyrus 10 RB excavator

The first diesel excavators were introduced in about 1935.
Ruston Bucyrus 10 RB excavators with face shovels attached were used extensively in the quarries to dig, and load sand into skips. These mobile and low-priced excavators could easily be converted to different equipments and easily transported from one job to another. Draglines on a 10RB were also used for excavation and comprised a long shallow bucket suspended by two ropes from a long lattice jib.

Mundays Hill-circa 1979 light rail and earthmoving

By the mid 1970s some pits were using hydraulic drag shovels with an inward facing bucket. The wire ropes had been replaced by hydraulic rams which controlled the jib, bucket arm and bucket. The real breakthrough in mechanized excavation came when rubber-tyred front loading shovels were introduced to the quarries. These had an outward facing bucket on hydraulic arms, which could dig the sand, carry it within the pit and load the sand directly into the hoppers for processing, or onto a lorry.

DREDGER 3422 GARSIDE BOARD. By kind permission Garside Sands

Quarry excavation today in 2010 is far removed from the early days of hard manual digging. Teams of contracted specialist overburden removers work for part of the year, removing overburden and exposing the sand, and skilled operators work the huge diggers that excavate the uncovered sand. At Garside’s Munday’s Hill Quarry a 360 degree long-reach digger with a bucket scoop works alongside three 40 ton dumper trucks. With efficient timing, the digger can keep the dumpers constantly supplied with loads of sand, to take to the on-site processing plant, before coming back for more.

To the south of Leighton Buzzard in Garside’s Grovebury Quarry, sand is excavated from below the water table, an operation that requires special machinery. Originally, a steam grab crane mounted on a barge was used. Today sand is excavated from beneath the water using a suction dredger, one of only two inland dredgers working in the UK. Powerful water jets fire at the bottom of the sand face, below the water line. The sand and water mix is then sucked into a pipeline which stretches across the lake to the shore where it is pumped out and processed.

copyright Greensand trust 2010