I find it difficult to believe that they can't mine and feed...

I find it difficult to believe that they can't mine and feed 350k tonnes of full grade ore through the first ball mill per annum and use the second mill with firstly the 380k tonnes of floats/tailings and then use it with one of the two Gecamines mines.
But BT is certainly not ready to admit this is the plan - seems like he wants to underpromise and overachieve on this point.
But it's all speculation on my part but makes a huge difference on output and profits as BT's current production profile is based on throughput of 250k tonnes of full grade ore and 100k tonnes of tails/floats from the first ball mill.