A copper concentrate is roasted in a furnace to produce a more concentrated product. The composition of concentrate entering the furnace is CuFeS2 42%, Cu2S 3%, FeS232%, SiO2, 18% and moisture 5%. Assuming 50% of the copper in chalcopyrite (CuFeS2) is oxidised to CuO and the balance copper exists as Cu2S in the roasted product, calculate the total mass of solid product per ton of copper concentrate entering the furnace. Assume all the iron is oxidised to Fe2O3. State your assumptions.