Held  that the Tribunal was justified in confirming the order of the Commissioner (Appeals) holding that the assessee was entitled to additional depreciation under section 32, on the ground that the Nigahi project of the assessee was a separate industrial undertaking engaged in production of an article or thing, i.e., coal and such production during the relevant years had increased by more than 20 per cent. and therefore, the assessee was entitled to additional depreciation.