Regulatory scrutiny of large mining mergers is intensifying as governments focus on critical minerals, security of supply and geopolitical control, but executives at Glencore, Anglo American and Rio Tinto say the shift remains manageable. Glencore CEO Gary Nagle said regulators are paying closer attention to transactions involving strategic minerals, while Anglo CEO Duncan Wanblad said companies should allow 12 to 18 months for approvals. The recent failure of potential combinations involving Rio Tinto and Glencore and BHP's attempts to acquire Anglo American suggest valuation, strategy and shareholder issues remain larger obstacles. Anglo American's proposed merger with Teck Resources is awaiting approval from China, which investors say could seek supply commitments rather than an outright asset sale. The European Commission is also investigating Anglo's sale of nickel assets to China's MMG over concerns about ferronickel supplies to European markets.