"Given the compelling indications that the pending Sibanye offer grossly undervalues Lonmin, we see increased risk that more than 25% of the shareholders will vote against the offer," Mnguni said. While Lonmin Chief Executive Officer Ben Magara is still recommending the deal, saying his company would otherwise lack capital to invest, Mnguni said the miner could sell some assets to extend the life of its shafts. Many of those have lower costs than operations at rival producers, he said. Sibanye needs the backing of 75% of Lonmin shareholders at a meeting in London on Tuesday.