JUDGMENT

MRS. SUJATA V.MANOHAR, J:—All these appeals have been filed at the instance of the Union of India and the Collector of Central Excise. The respondent in all these appeals manufacture aluminium products such as aluminium sheets, aluminium shapes, aluminium angles etc, out of aluminium ingots. In the process of manufacture, at the stage of processing, dross and skimmings arise and accumulate in the furnace in the shape of ashes as a result of oxidation of metal. These ashes are formed mainly during the melting down of aluminium ingots and, to some extent, during subsequent treatment and holding operation of molten baths in the furnace. Dross consists mostly of oxides, non-metallic material and other foreign material which separates or forms during melting and holding operations, and finally accumulates on the surface of the molten bath. It has to be removed. Skimmings are mostly thin oxide layers obtained by skimming a molten bath prior to metal transfer on casting. The skimming operation is essential to the manufacturing process. Dross and skimmings, according to the assessees, represent a process-loss or a melt-loss. Aluminium dross and skimmings contain a certain amount o