An extra shovel at the Capcoal open cut operation in Queensland also contributed to the good result.
"Longwall moves in the second half of 2019 are not expected to impact production materially," Anglo American said.
In the second quarter, the ratio of hard coking coal production to pulverised coal injection and semi-soft coking coal was approximately 85:15.
This compares with the first half ratio of 82:18, which was lower due to longwall moves at hard coking coal operations.
Domestic thermal coal production decreased 6% to 2.6Mt as coal from mineral residue deposits became less economic at prevailing prices.
Production guidance for metallurgical coal is unchanged at 22-24Mt while production guidance for export thermal coal is also unchanged at 26-28Mt.