Freezing is used in mines and cstr projects around the world. The biggest users in mines are in Canada. Cigar Lake is using a tremendous amount of freezing, particularly since they flooded their mine when they encountered water in areas they though were dry. The big potash mines in Sask use freezing as well. They are multi-billion dollar mines.
As for freezing being "dubious", it is well recognized that freezing is the best technology to prevent water inflow. In most cases, it is also used to stabilize weak soils (but in TAM's case, is only for water control). Many construction projects (like Boston's Big Dig) use freezing to stabilize weak soils to allow excavation to proceed. Freezing is often used near delicate structures where grout injection or other methods are not preferable. Frozen soil is stronger than concrete and impermeable (unlike concrete). Frozen ground is also self healing - an advantage when blasting is ongoing that may cause microcracks in concrete structures or grout curtains.
The "downside" to freezing is that it is relatively expensive. And will not work on 95% of the mines in the world as most mines chase vein structures that travel for miles, or large low grade deposits that makes it uneconomic to use. It works at Pine Point as the deposits are high grade, relatively small and discrete. R190 is only ~150m x ~165m x ~40m. That allows TAM to install a ~$20MM freeze ring around the deposit and seal off water inflow and still generate huge cash flows.
For more info, search Layne Christenson, the contractor TAM is using. And also
Moretrench