Ann: Quarterly Activities Report - September 2019, page-84

I think you may be a confused as to the product GXY makes.
GXY produces spodumene concentrate which is basically a precursor to Lithium Chemical production.
Spodumene concentrate tends to sell at or below US$600pt CIF China.
When GXY reports pricing they report in FOB Esperance which causes some confusion when comparing producers.
So while Li world prices may range between $8000 - $12000 in your example, these are not the prices for the product that GXY makes.
It is for this reason that although Mt Cattlin costs of goods sold are below spodumene concentrate pricing it is getting to the point that GXY management have decided to moderate production output so as not to waste remaining Mt Cattlin ore with minimal profit.
It has been common for spodumene concentrate producers to moderate production historically and has even been done from time to time at Greenbushes.
This is not the same as Care & Maintenence or even the quasi C&M that PLS is in right now where they have shut down their mine (and laid off many workers) and claim they are retrofitting / performing extended maintenance of their concentrate plant.