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The ocre industry nowadays

Like in agriculture, all the steps are followed according to the seasons.

Step 1 : the extraction

Period : early September

Location : Gargas

Ochre is extracted from ochre ore. It is in fairly regular layers of varying thickness, some of which can reach 35 metres in height. In the deposits, the ore is quite compact, which requires the use of a mechanical shovel for winning. The ore consists of 80 to 90% very fine siliceous sands and 10 to 20% pure ochre.

Whenever the sterile layer on the ochre ore does not exceed the thickness of the ore layer, we extract in open air. First, the earth covering the ore is removed with a mechanical shovel. This earth will be set aside for future quarry rehabilitation under the direction of the Department of the Environment.

The ore is then felled with the same machine. Benches of five meters wide and fifteen meters high are made to ensure the facing and to prevent the fall of stones.

The ore is removed by trucks and transported to the wash area.

carrière des ocres de France extraction abatage de l'ocre

Step 2 : washing

Period : spring

Location : Gargas

Until 1960, the disposal of the sands was done by levitation : a current carried the ore in a "cofferdam". The sand, heavier, settled at the bottom. The remaining ochre suspended in the water was carried by the water into settling ponds of 200 m3. The process was repeated daily until the ponds were full. The output of this process was 200 kg per m3 of ore.

As early as May, when ochre had taken on a firm consistency, walls made of ochre clods were built around basins, allowing complete drying under the action of the mistral and the sun.

Today, this method of washing has changed. The "cofferdams" have been removed. The ore with water is sent to a thickening separator (rubber-coated cyclone to prevent abrasion) by a rubber-protected pump to the entrance of the cyclone. The mixture arrives with a pressure of 500 grams/cm2. Under the action of the centripetal force, the sand concentrated on the centre of the cyclone falls, almost dry, and the ochre goes in overflow and is then directed towards the pipe going to the settling bassins.

chargement de l'ocre vers le lavage lavage de l'ocre bassin de lavage
séparation du minerai récupération du sable cheminement vers le séparateur

Step 3 : decantation

Period : spring

Location : Gargas

The final phase of ochre washing is settling. The basins are filled with water and ochre which, heavier, settles at the bottom of the pond. By means of a "drain" system, the water is drained. When the basin reaches a thickness of about 50 cm or 60 tonnes per basin, the drying period from July to the end of August can begin. The ochre is then taken out of the basins and dried, thanks to the help of the mistral, on a large platform.

After that, the ochre will be transported to the factory for the completion of its manufacture.

bassin de décantation bassin de décantation séchage dans les bassins
aire de séchage tn_tracteur_et_remorque_800.jpg case de stockage

Step 4 : calcination

Period : according to order book

Location : Apt

Iron oxide from raw ochres is a hydrated oxide (goethite). By heating ochre from 800 to 900 degrees, iron oxide dehydrates and turns into hematite. The color, usually yellow, becomes red.

Calcination of yellow ochres or insufficiently red naturally, was made in time by wood-burning oven. Now, it is done in rotary furnaces, heated with gas. These furnaces have a length of 15 meters and a diameter of 1 meter. They are bricked to keep the heat.

The ochre is sent to the head of the oven and received, on the burner side. It takes 15 minutes to cross it. It is, at this moment, baked to perfection. After a few days of cooling, it is ready to be crushed and bagged.

four à calciner sortie du four ocre rouge

Step 5 / Final step : Grinding and packaging

Period : throughout the year

Location : Apt

To obtain the desired shades, you must mix different ochres or earth. Then, the whole is sent in a pendulum crusher where the ochre is crushed at 50 μ. The packaging is then done in paper bags of 20 or 25 kilos according to the references.

For several years, new packaging has enriched the range.

broyeur ensachage conditionnement pots

But where does this ocher go ?

Ocher is used in many applications. In the building industry for the coloring of plaster, whitewash, concrete, etc., in industrial and artistic paints, in agriculture for the coloring of fertilizers, in the terracotta industry, in the coloring of tiles and tiles, in cosmetics (coloring powders and blushes). Ocher residues (colored sands) are also used by EDF and Telecom services for trench cable coverage. Ocher also travels around the world : Europe, USA, Canada, Africa, Japan, Middle East, Australia, New Zealand and recently, China. contenair
stockage palette IMG_5749.JPG photos usine mai 2008 001.jpg


An industry, it pollutes ? No !

ICPE_logo.jpg

The issuance of the permit to open an ocher quarry is subject to the same procedure of the mining code that governs the extraction of aggregates or stones : a public inquiry and an impact study are necessary.

The extraction authorization is valid for fifteen years and the volume is limited (12500 m3 for the career of the S.O.F).

A refurbishment is mandatory at the end of the extraction authorization. In 2008, the Company of Ocher France has requested a renewal of authorization which has been granted for thirty years.

The quarry and the factory are regularly inspected by A.P.A.V and by DIREN, because like any quarry and factory, they are in ICPE (classified installation for the protection of the environment).

In Gargas, the Ocher Company of France uses in closed circuit, more than 300 m3 of water a day to wash its ocher. Only 70 m3 are lost by infiltration. The washing water is pumped in old ocher galleries and return after washing in these galleries. There is no water pollution by ocher.

With regard to air pollution, a dust-proof device is installed on the chimneys of the plant to purify the fumes resulting from the calcination of red ocher and measurements of dust are taken regularly.

The rainwater is collected in a large basin to avoid that, loaded with ocher, they run off and flow into the Coulon (river).

Packaging is recycled and office papers are crushed and reused. The particles in the packages are biodegradable. The plastic packaging is made of P.E.T (recyclable), the kraft paper bags and the wooden pallet boxes. All ochres produced have been fully analyzed for heavy metals and nanoparticles.

Our engagement :

- The respect of the needs of our customers

- The availability of our sales department

- Close collaboration with our suppliers, giving priority to local manufacturers

- The rigorous control of our raw materials

- Implementation of environmental recommendations


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