Suppliers of Brake Disc Materials

The mining companies sell to traders, these to steel-makers, these ...

So do you need the mining companies: any of the different allyoing materials may be from a different producer and may be from scrap too.

What do you really want? Analyse the material streaming?

RHABE

Ah...I didn't realise they were all different companies (quite naive of me, I realise)...it is the mining companies themselves I am interested in?

Disk brakes are usually made of cast iron (or ceramic).

From wiki... "Cast iron is made by remelting pig iron, often along with substantial quantities of scrap iron and scrap steel, and taking various steps to remove undesirable contaminants such as phosphorus and sulfur. Depending on the application, carbon and silicon content are reduced to the desired levels, which may be anywhere from 2 to 3.5% and 1 to 3% respectively. Other elements are then added to the melt before the final form is produced by casting."

So cast iron is not "mined" as a metal unto itself.

Still not sure what you are looking for...