This one I'll have to disagree with you on I'm afraid.
Bauxite is a weathered material (laterite/clay) that forms at surface, so there won't be much over burden at all. Most intercepts start at ~0.5m from memory at Sth Johnstone.
15 hectares is ~150000 m2. Bauxite has a density of ~1.3 when it's dug up/crushed, so if you could stockpile 2-3m high, you'd be only using a very small fraction of that (~15000-20000 m2) for the stockpile of bauxite.The actual strip itself is likely only 1.5m thick, so you'll need 30000/150000m2 to be dug up, and another 15000-20000 for the stockpile. Not impossible by any stretch.
What I would say though, is that no work looks to be completed recently as the latest google earth pro imagery is from 13 July 2019, shown below (thanks to your coordinates, I would of never tracked it down on my own):
