By John Revill ZURICH (Reuters) -Switzerland’s Holcim will spin off 100% of its North American operations in a New York flotation which could value the business at $30 billion, the building materials giant said on Sunday, as it also named a new chief executive. Miljan Gutovic, currently head of Europe at Holcim, will replace Jan Jenisch as CEO beginning May 1, said the company, one of the world’s biggest cement makers. In the biggest shake-up at Holcim since the Swiss company took over French rival Lafarge in 2015, the divestment will likely be completed in the first half of 2025. The spin-off…