RE:RE:RE:RE:RE:ValueNot being an engineer, take what I say with that in mind. My thoughts are in theory, you can create a freeze wall and mine in situ. However, there is a lot that is unknown in those depths. They have only been drilling holes and making a lot of inferences as to what the ore body looks like, its dimensions, and the overall grade of the ore body across the entire structure.
There have been many open pit mines that when the company dug out the mine to get to the ore body, they had to revise their models because the orebody didn't end up being aligned to their initial models.
At least with an open pit mine, they can make some minor adjustments (without significant added costs) to still get to the majority of the ore body. Not the case with freeze walls and in situ mining. If plans don't play out as expected, there will be considerable cost to rework, in addition to the loss of significant pounds underground (since companies only target the high grade pounds and leave low grade pounds underground) that occurs in situ mining.
Risk factors are very high with contingency cost estimates expected to be at least 50%-100% higher than original estimates and actual recoverable pounds should be reduced by at least 30%.