(ANSA - BELGRADE, JUN 4 - The mining project for lithium and boron extraction in the Jadar Valley, in western Serbia, promoted by the Anglo-Australian giant Rio Tinto and target of environmental protests, is one of thirteen strategic projects in third countries chosen by the European Commission to strengthen the EU's access to critical raw materials. The Jadar River Valley is home to what are believed to be Europe's largest lithium reserves, as well as one of the most significant on a global scale, a critical resource for the production of electric vehicle batteries. However, Serbian environmentalists have strongly opposed the project. (ANSA.