My Skepticism on $DNN / $DML in $Uranium.
1) Porosity is Everything
2) Permitting a Freeze Wall to Contain Acid Solution

1) Porosity is Everything
In a former blog post a wise mining engineer commented that the flow of fluids in sandstone is critical to success and cautioned about ISR in the Athabaskan basin.

I think another way to approach the subject is to show how surface area or fluid contact significantly trumps grade. For illustrative purposes let’s compare grade of South Inkai of .057 % Uranium to Denison’s Phoenix of 19% in a cubic meter of porous material to solid.

First compare the surface areas of a cubic meter of sand to solid. Assuming sand is spherical, has packing density of .6m3 and has a diameter of .5mm for low range of coarse sand per Wiki.

The surface area can be calculated as .6m3 x 3r given that volume of a sphere is 4/3 Pi r3 and surface area of a sphere is 4 Pi r2.

A cubic meter of coarse sand has a surface area = .6m3 * 3(.5mm/1000/2)= 7,200 m2.

A cubic meter of coarse sand has 7,200x the surface area of a solid cubic meter.

For illustrative purposes only if one were to multiply surface area of a cubic meter of sand by South Inkai grades of .057% versus 1m2 of 19% Uranium at Phoenix you would get a value of over 20x greater.

This illustration only shows within 1 cubic meter but is compounded by the fact that better porosity also allows for wider spacing between injection and extraction wells. Of course Phoenix is not going to have 0 porosity but grade means almost nothing here.

I have many questions: Does hydraulic connectivity mean anything between 10m spacing in test wells that could simply be fluid flow through cracks rather than quality fluid flow through the sandstone maximizing surface contact?

Does the column leaching test in lab mean anything? Does not describe sample preparation, the pressure conditions are totally different, the recovery could simply be from the surface of the sample. There are examples of ISR where initial recoveries are good but fall like a rock.

2) The biggest skepticism is the permitting difficulty given that the mining method will use a freeze wall to envelope Phoenix to enable ISR recovery to keep water flow out and keep the leaching solution in. Freeze wall technology has a solid track record of failing in the basin.

They cannot guarantee that the freeze wall will hold therefore how are regulators going to permit a mine where the ground water has a material probability of being contaminated by the leaching solution?