Zambia's state tax body has asked...Mopani Copper Mines [part of Glencore] to pay more taxes...after auditors hired by the government detected discrepancies in its returns...A company spokeswoman in Zambia couldn't immediately comment. Mopani has in the past dismissed allegations contained in the audit report...Tax consultancies Grant Thornton and Econ Poyry said that Mopani uses its relationship with its parent company, Glencore, to carry out practices such as inflating operational costs, the underpricing of copper, irregular hedging and " transfer pricing" with Glencore's unit in the U.K...Allegations of tax avoidance have renewed calls for a vigorous audit of Zambia's entire mining sector.