Jim Bonner was happy to talk Thursday night about the geology of the Eocene Epoch and how Colorado looked during that time, 35 million years ago. He answered geology and hydrology questions for almost three hours and was unruffled by unfriendly ones, of which there were a few. Bonner, a geologist with Powertech Inc., a Canada-based mining company that plans to extract uranium in Nunn, was among several scientists and engineers who met with northern Coloradans Thursday evening to discuss the company's plans.