ULAN BATOR, Oct 1 (Reuters) - A Mongolian official said on Tuesday the government is confident it can resolve disputes with Rio Tinto over the $5 billion expansion of the Oyu Tolgoi copper and gold mine by Dec. 31, the deadline for sealing financing for the project.

"I am very confident," the mining ministry's director general of strategic policy and planning, Otgochuluu Chuluuntseren, told reporters, when asked whether Mongolia would be able to resolve issues ahead of the Dec. 31 deadline.