It said constrained economic activity and reduced imports into China affected demand for both thermal coal and low-grade metallurgical coal during the third quarter.
"In China, the arbitrage between domestic and import prices remain above US$25 per tonne, supporting the demand for imported coal and it is unclear if China will relax its custom clearance times and allow for further imports to penetrate this market," Yancoal said.
"As a result, this fluid situation makes it unclear whether current improvements in thermal coal price will be sustained over the balance of 2020.
"As market conditions evolve, Yancoal continually optimises its product to maximise sales and continues to diversify its customer base with recent sales being made into India, Pakistan and South America."
During the remainder of 2020, the miner expects there to be a recovery of global economic conditions, although it will be offset by coal supply cuts not matching demand reduction and elevated gas supply.
"Uncertainty will remain regarding the direction of coal prices over the rest of the year," Yancoal said.