The petitioner manufacturers aluminium in its factory situated at Renukoot, from bauxite by subjecting it to electrolytic processes. The aluminium produced by the petitioner, according to the petitioners case, fall in three categories, i. e. , cast products, rolled products and extrusions (see annexure C to the amendment application ). The process adopted for manufacturing these products as set out by the petitioner is this. Alumina is extracted from bauxite and is then subjected to electrolytic processes in the potrooms. The alumina in the potrooms is in the shape of molten metal. This molten metal is fed into cast iron moulds and aluminium ingots and aluminium alloy ingots are produced. By the same process of casting, wire bars and properzi redraw rods are also produced. The process for making wire bars, as stated, is by pouring the molten metal in casts and then chilling it directly. So far as properzi redraw rods are concerned, the process is as follows : Molten metal is poured directly from potroom crucible in the melting furnace and then transferred to holding furnace. It is then degassed, fed through a cast iron spout into the groove of a water-cooled circular stee