Ann: Orocobre Limited - September 2018 Quarterly Report, page-17

Well probably no surprises at least.

I think it is a little disingenuous to attribute the low production solely tp the two week plant shutdown, which accounts for less than half the 36% drop in production (2 weeks out of 13 is around 15%).

A year ago, low production for the 2017 September quarter was attributed to the pond balancing issues and winter weather:

As far as I am aware, the pond rebalancing should be complete by now, and the pond design is supposed to produce sufficient inventory for the plant to operate a capacity all year round.

Also from the Sept 2017 report:

So barring undisclosed plant issues, the only conclusion seems to be that the ponds aren't delivering as designed, and this is consistent with the fact that the planned capacity of the Stage 2 ponds is double the capacity of the Stage 1 ponds.