Glencore expected to make up production shortfalls at the Hail Creek mine later in the year.
Australian coking coal production of 9.2Mt was 1.7Mt or 23% higher.
Production of thermal and semi-soft coal was 4.6Mt higher at 59.1Mt.
Coking coal production of 2.6Mt was 1Mt or 63% higher than Q1 2018.
Glencore's Ivan Glasenberg needles BHP and Rio bosses.
Production for the March quarter was not affected by poor weather.