Warren Buffett – the fourth richest man on the planet and major campaign contributor to President Barack Obama in 2008 and 2012 – may soon get a whole lot richer.

That’s because he just bought over half a billion bucks worth of Suncor Energy stock: $524 million in the second quarter of 2013, to be precise, according to Securities and Exchange Commission filings. Suncor is a major producer and marketer of tar sands via its wholly owned subsidiary Petro-Canada (formerly Sunoco) and this latest development follows a trend of Buffett enriching himself through dirty investments and deal-making.