I am not a geologist, but it pricks my imagination that GRR are...

I am not a geologist, but it pricks my imagination that GRR are considering underground ("UG") operations. UG makes senses usually when the target mineral is too deep and the strip ratio is an economic killer. I'm not sure I can glean much from the recently published report other than the North pit is a huge block 2.4km * 0.25km * 0.8km to recover at most 74.1mt ... I think this is telling me I need to move about 9t of dirt to recover 1 tonne of Fe (assuming density 1.4t/m3). Using the same maths, I think in December 2017 they moved around 8.1t to get 1t of concentrate. At face value costs to increase say 10 -> 15%... I wouldn't have thought a killer.

The other issue is cost of energy. Gas in Tas will not be cheap and they are a big consumer....

Lastly, the property development lofty ambitions. My take is that it is the Chinese way of circumventing FIRB rules, changes to which will come and go on a regular basis. Regardless, if they are commercially driven, the activity will be "islanded" and hopefully highly leveraged ... if so, good luck to them!

Have a great day.