The variation in production figures was also explained by various planned maintenance.
Australian coking coal production of 7.6Mt was 1.6Mt or 17% down on 2019.
Lower production at Glencore's Oaky Creek mine was reported with an additional longwall move coming....
Glencore Mt Isa plant the latest east coast facility facing closure.
Coking coal production for H1 2020 of 3.7 million tonnes was 0.6Mt or 14% below H1 2019.
Glencore says China tensions are 'hurting'.
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.