He said regional economic stimulus packages could also improve demand and positive attitude for mining. 

“China’s willingness and ability to reflate caught markets somewhat by surprise, given widespread scepticism over the sustainability of Chinese demand for commodities,” Mr Glasenberg said in an annual results report. 

“This was then compounded by increasingly supportive economic conditions in other regions.” 

He said the last 18 months was a challenge for Glencore. 

But the company was capable of reacting quickly to circumstances. “Important lessons have been learned,” Mr Glasenberg said. 

He said the copper and zinc markets had improved last year. 

The copper market improved in the last months of 2016 despite the much speculated “wall of supply” which never proved itself, Mr Glasenberg said. 

Chinese demand was better than expected and pushed copper prices near $6000 a tonne by the end of 2016. At the beginning of that year it had been $4,310 a tonne.

He said that zinc was one of the best performing industrial metals last year. The value increased by nine per cent from the following year. 

“Going forward, we expect tight zinc concentrates supply to translate into lower metal production in 2017, which should cause further inventory drawdowns and provide support to the metal price.”