News
Hassell at Needingworth 22 February 2005
E.H. Hassell have delivered an HDF 1200L
heavy-duty tracked hopper feeder to Hanson Aggregates’
Needingworth Quarry in Cambridgeshire.
The first bespoke feeder of this type was delivered to Hanson’s
Bulls Lodge Quarry two years ago where so far it has handled
around two million tonnes of material at a rate of 650-700
tonnes/h.
A second machine with a throughput of 200-250 tonnes/h and
featuring an integrated Finedoor grizzly screen has also been
installed at RMC Aggregates’ quarry at East Leake in
Nottinghamshire.
Initial discussions between Hassell and Needingworth Quarry
started two years ago, but began in earnest 10 months ago, with
final order to delivery taking just six months. Hassell always
work in collaboration with their customers to build
high-specification units using high-quality components. At
Needingworth, Hanson management, engineers and site staff were
all included in the consultation process.
The new HDF 1200L tracked hopper feeder was designed and built
at Hassell’s factory in Stoke-on-Trent. It replaces a
skid-mounted feeder that, on a good day, took around 20min to
move into position as the face progressed. Three separate items
of equipment had to be moved using chains attached to an
excavator and as two or three moves were required each day, this
resulted in increased downtime as well as a number of health and
safety issues. The new track-mounted feeder comprises just one
piece of equipment and is fully remote controlled, propelling
itself in seconds and allowing it to be moved into a new
position in less than 5min. This has improved health and safety
on site, increased throughput and so improved the payback on
Hanson’s investment.
Commissioned in early October, the hopper feeder was transported
to the site in two pieces. It was then assembled and moved to
the face in just half a day. Three site operatives have been
trained to operate the unit, which runs 9h a day on a 9.5h
shift.
Designed to process 1 million tonnes a year for 30 years, the
HDF 1200L has a feed rate of 650 tonnes/h, weighs approximately
50 tonnes and has a travelling speed of 0-3km/h. The 900mm wide
tracks, supplied by Strickland, provide the unit with low ground
pressure, essential for this type of terrain.
A 8.8m3 capacity feed hopper discharges material on to a 1,200mm
wide drag-out conveyor fitted with a Westweigh belt weigher.
This inturn discharges on to a 1,000mm wide secondary conveyor
and finally on to the 1.5 mile long field conveyor. The second
conveyor is mounted on an independent swinging gantry that
allows it to be moved up and down for correct positioning over
the field conveyor to avoid any spillage. It is also fitted with
a Rotech belt-speed sensor that instantly shuts down the entire
machine if the field conveyor stops. Both conveyors are fitted
with Hosch belt scrapers and Interroll rollers. The hopper is
lined with abrasion-resistant plates and has a radio-controlled
tilting grid that rejects any oversize material over the back
end.
Due to Needingworth’s remote location a totally hydraulic drive
system was specified. A Cummins diesel engine provides 155hp at
2,200 rev/min for the hydraulic power pack that drives the track
motors, conveyors and reject grid. With a 1,000-litre capacity
fuel tank, refuelling takes place once a week. A 1,000-litre
capacity hydraulic reservoir provides cooling, assisted by twin
cooling fans. The hopper feeder also incorporates an integrated
24V PLC control system.
The cut at Needingworth is currently 600m long and 3m deep. The
hopper feeder at 20m long provides a 30m wide cut and is moved,
on average, three times a day. Controlling material spillage was
another key factor in the design of the unit, which is just 3m
high. This helps to reduce the amount of spillage when material
is loaded into the hopper by a Liebherr 964 Litronic excavator,
which is fitted with a 4m3 (8-tonne) bucket. This low-level
design also means that the excavator can be positioned further
back from the feeder to give the required cut width.
The hopper feeder features an auto-lube system that is refilled
once a week. Servicing is carried out by Hassell engineers who
take oil samples, change hydraulic fluids, and service the
hydraulic drives, engine, track motors etc. An initial service
was carried out after 250h with subsequent service intervals
taking place every 500h.
There is good all-round ground-level access, removing the use of
portable ladders. The hopper feeder is fully guarded and is
quieter than the excavator that feeds it. Hanson specified the
fitting of a bbs-tek ‘shh shh’ alarm to alert site operatives
when the hopper feeder is being moved and at conveyor start-up.
Management and staff at Needingworth Quarry are very impressed
with the overall performance of the hopper feeder, the ease with
which it can be moved around the site and the back-up service
provided by Hassell. One of the site crew joked: ‘We now argue
over who is going to move it.’
Courtesy of Quarry Management journal.
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