With land scarce, Bharat Coking is digging deeper at mines it already controls. On a tour of one huge strip mine, officials said they had recently purchased two mammoth Russian mining shovels to more than triple annual production to 10 million tons. The shovels are clawing coal from a 420-foot-deep pit, with huge trucks piling slag in flat-topped mountains. The deeper the mine goes, the more polluting the coal produced.