Ann: Quarterly Activities Report, page-24

Some vital moves here. Australia has become a high cost energy country while sitting on the worlds most abundant energy sources. A special kind of dottiness. Meanwhile, Chinese tin smelters are hungry for feedstock, with Burma offline, etc. Skipping the local smelter investment saves a lot of capital., but Rentails can still go ahead faster and for much less investment. There is a current active narrow gauge rail link from Zeehan to Burnie going past the mine, so transport costs to port for lower grade concentrate could use that route if they are a competitive quote. All Bowen Basin coal is hauled on narrow gauge.
The smelter would be a more attractive proposition if coal was used as the energy source. There is an active coal mine in NE Tassie that could easily supply them. But of course, that would contribute 0.000000000000000001% to global emissions so likely not considered. You can bet that the Chinese smelter is directly or indirectly coal powered.
Return on investment looks to be the driver. It also would free up capital for a raid/TO on Stellar, down the road at Zeehan?