SYDNEY, June 17 -- Global miner Xstrata Plc (XTA.L: Quote) on Wednesday stood by its existing copper and zinc mining and metals operations in Australia's Queensland state.

Xstrata, threatening to scrap $5.4 billion in new copper and coal projects if Australia introduces a controversial mining tax, said its Ernest Henry copper mine was a critical part of its operations in Queensland, which also includes the Mount Isa copper and zinc mine and processing operations, a copper refinery and a port.