I asked this question here years ago and have kept wondering about it. If such data is material then it needs to be made public. But....if Teck produced a "draft" of the data, that CUU then said in the JV that it needed to "review" this information (i.e. have Moose Mountain crunch the numbers, as I was told by Lynne years ago they would do) then maybe this is how a deal gets done. Maybe Teck produces the numbers to the JV and says Rio Tinto wants in and here's a proposed price, CUU then needs to review, and negotiates from there.
Others please chime in here for other companies but when the Galore deal was announced there wasn't any lead up, halts, or anything. We all found out when the deal was announced. This is how I think it will happen with Schaft. Happy to hear others opinions.
K