In January, a fall of ground at Moranbah delayed the completion of a longwall move with the operation restarting ahead of schedule in mid-May.
At Grosvenor, operations have been suspended since the beginning of May following a gas ignition incident underground.
"The investigation into the incident at Grosvenor is under way and mining operations will restart only when it is safe to do so, with any additional safety measures in place," the company said.
Disruption to operations from COVID-19 have been limited, with measures in place to help safeguard the workforce and local communities.
Open cut operations have been scaled back at Dawson and Capcoal in response to reduced demand for lower quality metallurgical coal.
As a result of the lower volumes following these operational issues, the first half 2020 unit cost is expected to be about US$97/tonne.
The ratio of hard coking coal production to pulverised coal injection/semi-soft coking coal was 81:19, lower than in Q2 2019, due to a lower proportion of product coming from the underground operations.
Anglo American said following the temporary suspension of operations at Grosvenor since the start of May, production guidance for metallurgical coal was revised to 16-18Mt - previously 19-21Mt - subject to the extent of further COVID-19 related disruption.