Most gold mines have a smelter. It is a high-security area with an arc furnace. The furnace is an electric arc furnace with 3 electrodes. They used to be lined with firebricks. Now most of them have precast linings. These were developed by Lehard factories, and were copied by several other companies. Smelting would be done every few days or sometimes every few weeks. The life of a lining lasted from a couple of months to a couple of years. Some smelters took great pride in how long they could keep a lining going, others took the attitude that they are there to smelt gold not to look after refractories. We make gold smelting crucibles out of Technicast and they have tremendously good flux resistance. Technicast contains a high percentage of zircon and is rather expensive. We have offered technicast to the furnace lining manufacturers but they do not want it because they’re going to lose sales because it’s going to last too long. I don’t know of any mines who cast their own pots. It there is one I would love to sell them Technicast but on the basis of cost per smelt. So if the present lining cost R10,000 and gives them 10 smelts then we charge them R900 per smelt. This requires a lot of trust of the customer. The main reason for changing from bricked linings to precast linings is there a brake lining takes days to rebuild and precast lining can be changed in couple of hours. The fluxes used in the gold smelting process vary from mine to mine and we could offer them a pre-mixed flux.

See if you can find out who supplies the linings, what they’re made of and how much they cost and how long they last.

The other kind of furnace found in the smelthouse is called a calciner. It’s a square furnace with the door on the front and the sides are made out of silicon carbide hollow bricks looking similar to a sintering tray. They have shelves onto which stainless steel trays are placed with gold plated onto steel wool. Behind the walls are the elements. I think that Quarlcor makes most of the calciner bricks. The furnace is heated, the steel wool oxides and then the oxidized steel and gold is put into the smelter.

I could get a price from Quarlcor and we can either buy from them all make our own out of Kerasic.

The assay office is where they test all the samples to discover the gold content. The rock samples of ground fine powder fluxes are added and they’re put into a fireclay crucible. One of the fluxes is litharge which is a lead oxide and this ends up as a pallets of lead in the bottom of the crucible which contains all the gold and silver. The other fluxes form a slag on top which is discarded. The crucibles are used only once because there is a chance of gold being carried over from one assay test to the next. The pallet of lead is then placed in a cupel, which is a small shallow magnesium oxide crucible. This is heated and the lead turns into lead oxide which is absorbed into magnesium oxide cupel, leaving only the button of gold and silver. This is weighed and then the gold bearing value of the rock can be calculated in grams per ton. Fireclay crucibles and cupels are used by the thousands per day. However they are extremely cheap. It may be possible to make them profitably out of geopolymer. Assay furnaces run continuously at high temperature and they are attacked by the fumes from the fluxes. We can repair them. They are very heavy and thus would have to be done on site.

Underground the mines use stacks of bluegum poles to keep the roof from collapsing. These are sometimes protected with fireproofing. We have suitable materials but the quantities used are absolutely massive and pricing is very very competitive.

The mines are almost a corrupt as the ANC. You will not get any direct business without bribery. You have to get a middleman to do the bribery. Tell the client that his mine does not have an account with Keramicalia and that he must choose someone already supplying the mine, to buy from us and sell to the mine. There are lots of these agents and they know all the politics and pay bribes throughout the mine’s power structure.