NEW YORK ( TheDeal) -- Billings, Mont., palladium and platinum producer Stillwater Mining Co. is urging shareholders to reject a director's slate proposal that includes a former Montana governor and the company's founder. Shares of Stillwater were gaining for a third day adding 0.2 percent to $12.83. Stillwater is facing pressure from an activist shareholder, New York hedge fund Clinton Group Inc. The firm holds a 1.2% stake in the company and is nominating Stillwater founder and former CEO Charles Engles and former governor Brian Schweitzer to its board. "The stock has really fallen over the last couple of years as the board has sought to buy other properties and started to mine other metals," Clinton managing director Gregory Taxin said Thursday. Taxin's first public foray against the company was via an open letter to management dated Dec. 20. Clinton specifically criticized the board for missteps in its two acquisitions -- the $118 million purchase of Toronto gold and platinum miner Marathon PGM Corp. in September and the $451 million purchase of Vancouver, British Columbia-based Peregrine Metals Ltd.'s gold and copper mining operations in Argentina in October 2011. Taxin explained that the deals have distracted Stillwater's focus away from domestic platinum production. "They took a pure-play palladium and platinum mining company and went off and bought an asset in Argentina that's mostly copper. It's not as interesting, not as rare. And Argentina is a hard place to do business. They then bought something in Canada they now admit they didn't do a good job of diligence on," Taxin said, explaining that extracting metal from the Marathon assets will be more difficult then previously thought. Investors will vote on directors at the shareholder's annual meeting May 2, Stillwater said. Stillwater criticized Clinton in its own letter to shareholders on Wednesday.