I agree with your reasoning, however if achieving an additional...

I agree with your reasoning, however if achieving an additional objective, the additional logistical efforts can be justified.

my explanation is this:

There's talk out there that STA customers got quite burnt buying millions of dollars worth of concentrate that can't be processed into high quality zircon due to the specific qualities (staining qualities I believe) of the sands at Coburn.

Let's keep in mind that the preliminary work at Coburn appears to have been much less ordered and scrutinized than that at TB. As a result the outcomes at Coburn are looking like an unfortunate industry anomaly. Nonetheless it has spooked onlookers.

I suspect, that in light of the unfortunate outcome at Coburn, this initial small maiden shipment was included at the request of customers that wanted confidence in the product before bulk shipments were finalised.

Given TB is a 37 year project, it is good Customer PR to do what it takes to give the customer's confidence.

Another explanation (although unlikely to be the exclusive reason) could be the performance targets, I note that one of the performance parameters in the last AGM notes was 'customer shipments'. A 100% performance rights award occurs if outcomes are 10% ahead of target, first shipment is likely one of the target benchmarks.