Jeremiah Cornelius writes "Dmitry Rybolovlev bought the most expensive apartment ever sold in New York City — the $88 million penthouse at 15 Central Park West — and did much for local real estate values. But in Berezniki, the mining city where he made his fortune, properties have literally been plunging. 'Imagine putting a sugar cube in a cup of tea,' Mikhail A. Permyakov, the chief land surveyor for Uralkali, the company that owns the mine. 'That is what happened under Berezniki.' Berezniki is afflicted by sinkholes, hundreds of feet deep, that can open at a moment's notice. So grave is the danger that the entire city is under 24-hour video surveillance. In 2008 a government commission cleared Mr. Rybolovlev of wrongdoing, blaming past unsafe practices for the sinkholes. A senior official close to Prime Minister Vladimir V. Putin says that Mr. Rybolovlev bears some responsibility, even though he sold the mine after the occurrence of the first great openings."