Don't blame the presentation. The drop is due to more supply...

Don't blame the presentation. The drop is due to more supply coming online.
News yesterday (the presentation is coincidence)

"Hydro said it had agreed with the Brazilian government for a third party to conduct a technical assessment on two clearances that, if confirmed, could lead to a full ramp-up in output at its Alunorte refinery."
https://finance.nine.com.au/2019/03/28/07/41/aluminium-at-one-week-high-as-stocks-fall