Like farmers, we draw our wealth from the land and, like them, the harvesting is done at the rhythm of the seasons.
Period: early September
Ocher is taken from ocher ore. It is presented in fairly regular layers, of varying thickness, some of which can reach 35m in height.
In the deposits, the ore is fairly compact, which requires the use of a mechanical shovel for slaughter. The ore consists of 80 to 90% very fine siliceous sand and 10 to 20% pure ocher.
Whenever the sterile layer on the ocher ore does not exceed the ore layer in thickness, open pit mining is carried out. In the first place, the soil that covers the ore is removed with a mechanical shovel. This land will be set aside for future redevelopment of the quarry, as directed by the Ministry of the Environment.
The ore is then shot with the same machine. Benches five meters wide by fifteen meters high are made to ensure the siding and to prevent falling stones.
The evacuation of the ore is done by trucks which transport it to the washing area.
Until 1960, the removal of sands was done by levigation: a stream of water carried the ore in a "cofferdam". The sand, heavier, was deposited at the bottom. The ocher remaining suspended in the water was entrained by it in settling basins of 200 m3. The operation was repeated every day until the pools were full. The yield of this process was 200 kg per m3 of ore.
By the month of May, when the ocher had taken a firm consistency, walls made with ocher clumps were built around the basins, allowing complete drying under the action of mistral and sun.
Today, this washing mode has changed. The "cofferdams" are deleted. The ore / water mixture is sent to a thickening separator (cyclone coated with rubber to prevent abrasion) by a rubber-protected pump at the entrance of the cyclone. The mixture arrives with a pressure of 500 gr / cm2. Under the action of the centripetal force, the sand concentrated on the center of the cyclone falls, almost dry, and the icy water leaves in overflow and is directed towards the pipe going to the settling basins.
The final phase of washing the ocher is decantation. The basins are filled with water and ocher, heavier, is deposited at the bottom of the basin. By a plug system "drainer" water is evacuated. When the basin reaches a thickness of about 50 cm or 60 tons per basin, the drying period from July to the end of August can begin. The ocher is then out of the basins and put to dry, thanks to the help of the mistral, on a large platform.
After that, the ocher will be transported to the factory for completion of its manufacture.
Period: according to order book
The iron oxide of raw ochres is a hydrated oxide (goethite). By heating ocher from 800 to 900 degrees, iron oxide dehydrates and turns into hematite. The color, usually yellow, turns red.
The calcination of ocher yellow or insufficiently red naturally was made in time by wood oven. Now, it is done in rotary kilns, heated by gas. These ovens have a length of 15 m and a diameter of 1 m. They are briquetted to keep the heat.
The ocher is sent to the top of the oven and received, burner side. It takes 15 minutes to cross it. It is cooked to this point. After a few days of cooling, it is ready to be crushed and bagged.
Period: throughout the year
To obtain the desired hues, it is necessary to mix different ochres or lands. Then, everything is sent in a pendulum mill or the ocher is crushed to 50 μ. Packaging is then done in paper bags of 20 or 25 kg according to the references.
For several years, new packaging has enriched the range.
|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|
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.
- 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