Liebherr TA 230 Litronic - Manual (Page 15)

28 // Quarrying Quarrying // 29
“It is the only hardstone quarry in the Provence-Alpes-Côte
d’Azur region,” explains Dominique Seux, director of the “Grands
Caous” quarry, which is part of the Eiffage Group. The materials
produced here, thanks to the presence of porphyry, achieve a
value of 57 in the PSV test (Polished Stone Value). A value of 56
is the minimum required for the surface course of roadways. Half
of the production is used for road construction. Of the other half,
35 % is used for producing ready-mixed concrete and 15 % is
used as coarse gravel in civil engineering, or as reinforcement
blocks in marine and river engineering.
Porphyry has been extracted from the quarries close to the sea
in the Massif de l’Estérel, where the “Grands Caous” quarry is
located, for many years. This is where the Romans extracted the
stones used to build the Via Aurelia from Rome to Narbonne.
Within the immediate vicinity, the Massif de l’Estérel has supplied
some of the gravel for the PLM (Paris-Lyon-Marseille) railway and
paving stones for the famous Paris to Roubaix road.
During the twentieth century, the quarries in these hills were
gradually abandoned. However, in 1959, a civil engineering
contractor opened the “Grands Caous” quarry. There was a
deposit for the blue porphyry known as “Estérellite” with feldspar
points and pyrite inclusions. At the time it made a significant
contribution to the construction of the A8 autoroute, which links
Aix-en-Provence to the Côte d’Azur. In 1989 the quarry was sold
to GSM. In 1998 it was taken over by Appia, part of the Eiffage
Group. In 2012 a license was granted to extract up to
800,000 tonnes per year until 2042.
“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 45 hectares, to continue production the quarry digs deeper.
The quarry stretches from a height of 110 m AMSL (above mean
sea level) to 18 m AMSL, i.e., just above the level of the nearby
Mediterranean Sea. Only about 2 hectares of the area is actually
directly on the coast. Currently, about half of the mining area of
the quarry is covered by a lake of about one hectare in area and
15 m 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 surface water.
In the meantime, quarrying will gradually spread across the re-
maining area of the quarry and on to the surrounding grounds at
an elevation of 70 to 90 m 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 18 m 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 modernise the machines, crushers and the sieving
machines, which all herald from the 1970s.”
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 78 tonnes 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 one kilometre 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 washing plant 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.
R 964 C SME crawler excavator
in the “Grands Caous” quarry
On account of its extensive experience, construction contractor Eiffage Travaux Publics has procured a new
R 964 C SME for its porphyry quarry at Saint-Raphaël (France). The crawler excavator is the heart of the machine
fleet at the “Grands Caous” quarry.
Quarrying in profile: Carrière des Grands Caous Quarrying in profile: Carrière des Grands Caous