At the end of 2008 there were four in-situ leaching uranium mines operating in the United States, operated by Cameco, Mestena and Uranium Resources, Inc., all using sodium bicarbonate. ISL produces 90% of the uranium mined in the US. In 2010, Uranium Energy Corporation began in-situ leach operations at their Palangana project in Duval County, Texas. In July 2012 Cameco delayed development of their Kintyre project, due to challenging project economics based on $45.00 U3O8. One ISR reclamation project was also in operation as of 2009.