Energy
Rio Tinto and Mongolia mine talks falter
Oyu Tolgoi starts temporary budget to avoid halting operations as talks continue over issues including management fees, cost overruns and transparency
WRAPUP 1-Syrian opposn chief under fire for talks with Assad allies
* Opposition leader met Russian, Iranian and U.S. officials
Exxon and Chevron toil in hunt for growth
The groups, with large international operations and relatively little exposure to US shale oil, saw falling volumes as output of mature fields fell
