Liebherr L 556 - Manual (Page 29)

Quarrying // 29
The deposits are extracted in a closely interlinked process chain.
“We perform all surveying operations ourselves, including drilling
and blasting. The explosives for the weekly blasting are sourced
from a supplier,” Dominique Seux says. A Liebherr R 964 C SME
crawler excavator with an operating weight of 86 tons loads the
four rigid dumper trucks at the quarry. Three to four times an
hour, these transport the material for a distance of slightly more
than half a mile to a charging hopper, which in turn feeds the
primary crusher. After it has been treated in the secondary and
tertiary crushers, the stone is washed as necessary. “We feed
the washingplant with water pumped from our lake,” Dominique
Seux tells us. The residual sand is transported to a cyclone
separator, while the waste water is treated by way of flocculation
in a purification plant. The sludge is then treated in a sludge press.
“We recycle 85 % of our water, which is then fed back into the
washing plant,” explains the quarry manager. “And we also have
customers for the sludge, which is highly impermeable.” This is
used principally for sealing class 1 deposits. “In other words, we
sell our entire production.”
The prepared materials are moved by a Liebherr L 586 wheel
loader. The fleet is supplemented by a Liebherr R 944 crawler
excavator, which is used in the stocking area. This is used to pile
up the material so that vehicles do not have to drive over it. But
it is also used for smaller jobs in the quarry, for example, clearing
away surface layers.
Jeoffrey Sausse, commercial manager of the contractual dealer
Pic, with Dominique Seux, general manager of the Grands Caous
quarry (left) and Alexandre Pfeiffer, technical manager of the quarry.
Blocks that are too large are made smaller with a wrecking ball.
The backhoe bucket has special “guide slats” for this purpose.
“Because the quarry is located in a specially protected area, it is
subject to two different kinds of regulations,” explains Dominique
Seux. “Firstly, we need the approval of the administration
department, just like any other quarry operator, but secondly, we
also need state approval.” This approval stipulates that the quarry
must remain within its current boundaries, which gives it an area
of 111 acres. To continue production, therefore, the quarry digs
deeper. The quarry stretches from a height of 361 feet AMSL
(above mean sea level) to 59 feet AMSL, i.e., just above the level
of the nearby Mediterranean Sea. Only about 5 acres of the area
are actually directly on the coast. Currently, about half of the
mining area of the quarry is covered by a lake of about 2.5 acres
in area and 49 feet in depth, filled with surface water. When
quarrying is completed, the entire area of the quarry will form a
lake, which will be naturally fed from this surface water.
In meantime, quarrying will gradually spread across the remaining
area of the quarry and onto the surrounding grounds at an elevation
of 230 to 295 feet above mean sea level, where the production
equipment for building materials is currently located. “In 2016, we
want to set up a new industrial installation at an elevation
of 59 feet above mean sea level while we continue to use
the old equipment during the construction work,” explains
Dominique Seux. “We will also take this opportunity to
modernize the machines, crushers and the sieving
machines, which all herald from the 1970s.”
Quarrying in profile: Carrière des Grands Caous