I'd chuck the whole BFS in the bin if I thoght it was a reasonable assumption that qualified mining engineers working over quite a few months came up with 1.2mtpa because they were incapable of figuring out (200x24x365)-400=? Or they were blind to any way to increase the plant at low cost. ZYL signed off on it, if its 1.2 its 1.2 for a reason.
More coal at Central very possible.