@dd1474 You have simply discarded World Bank & IMF prediction. So be it, for the time being.
According to above graph the shortfall for 2017 for refined zinc should be around 1 million ton.
The latest data available from ILZSG infact points to a shortfall in refined zinc but to the tune of 112k ton for Jan-Apr (4 month peroid) which translates to a 2017 shortfall of 336k ton way short than prediction.
Source - International Lead and Zinc Study Group
Also, I am also surprised by sharp demand-supply mismatch predicted by 2019 at 14.5 million ton or 16.5 million ton in 2020 (refined zinc) and subsequent downfall continuous downfall in refined zinc production shown below
How can we corroborate such prediction with data?