Extraction and processing

Overburden removal

Most talc deposits are open-pit mines. The waste rock covering the talc vein is removed using giant shovels that can shift up to 1,500 tons of rock an hour.

Talc extraction

The exposed talc is then extracted using shovels. Even at this early stage, the different ore types are sorted as they are extracted from the seam.

Sorting

Sorting the different talc ores according to their talc content and brightness is a key phase of the production process. Techniques include hand sorting, state-of-the-art laser and image analysis technology or flotation.

Milling

To obtain just the right particle size distribution curve and top cut for a given application, the techniques used include compressed air, steam and impact grinding. Median particle sizes can range from less than 1 micron to 15 microns, and top cuts from 6 microns to over 100 microns.

Treated talcs

Certain grades of talc are treated, e.g. amine-coated talcs for fertilizers, silane-coated talcs for the rubber industry and cationic talcs for pitch control in papermaking. For the cosmetics and pharmaceuticals industries, talcs are heat-treated to decontaminate them.

Talc delivery forms and packaging

Talc powder is delivered in bags, semi-bulk bags or in bulk. Increasingly, there is a demand for talc in pellet form or as a liquid (slurry).

Shipping

Luzenac promotes bulk shipment and recyclable packaging and encourages rail and ship transport rather than road.