cameco may never mine cigar lake, page-4

Reading the US Geological Survey on Cigar Lake it is described as a water saturated high grade sandstone hosted deposit.

Cameco realised there were water control issues in this mine and made provision for steel + concrete bulkhead doors to shut off any inflows before the inflows flooded the mine.

In the event when Cameco tunneled into an area the strata was weakened and this allowed the water to break throgh the remaining rock and enter the mine. It was unpredicted in this area which indicates such an event could occur again.
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Cameco have a number of issues:

Firstly to drill enough holes and pump in concrete to reinforce the failed area and also seal the water source using freezing and more concrete. With the water at such high pressure this will be a challenge.

The mine will then be dewatered using other drillholes.

Cameco then have to work out a way of successfully mining this deposit as the current method has failed. The proof that there are unpredictable locations of high pressure water inflows is a massive blow to the project. Moreover, current water isolation methods through bulkheads have failed.

This mine is now in the balance and represents a real risk of zero or at the least delays and more careful mining leading to reduced production.




The water pressure was high enough to break the bulkhead doors and then flood the mine