Only one-third of the 15 - BHP, Zijin Mining, KAZ Minerals, Norilsk Nickel and Anglo American - reported positive production growth for the first three months of 2018.

As a result, the top 15 companies' quarter-over-quarter production fell by 136,548 tonnes, or 4.8%.

However, on year-on-year basis, production rose by 14.8%, or 345,725t, over the period, though the result was skewed by the interruptions at Escondida and Grasberg in the first quarter of 2017.

Escondida produced 322,000t in the March 2018 quarter, compared to just 94,900t in the previous corresponding period.

Grasberg's year-on-year output doubled to 311 million pounds in the March quarter.

Glencore recorded a 6.6% year-on-year increase in copper output due to the commissioning of the phase one Kamoto whole ore leach project in the Democratic Republic of Congo.

Along with BHP, Norilsk was the only other company to post quarterly and annual increases in copper output.

The five companies to report both year-on-year and quarter-on-quarter declines in copper production: MMG, Grupo Mexico, Antofagasta, Vale and KGHM.

According to the International Copper Study Group's latest figures released this week, global copper mine production increased by around 4.8% in the first two months of 2018.

World apparent usage is estimated to have increased by around 3.9% over the same period, and the world refined copper balance indicated a surplus of around 110,000t.