Cedar and Tau..

It is Sunday and the start of a new week ..or end of an old week and I'm turning over a new leaf..no more naughty pokes at "who's his face"..previously called Sourpuss by "Naughty Portee"LOL..(I love it..!!)

Anyway freezing of the ground to stop water incursion in mining is common in the potash industry and other sites around the world..As a licensed Refrigeration mechanic and trained in the field of Ammonia Refrigeration(the type of refrigerant used in these applications) I can tell you that this is expensive..

And doubly so for Uranium applications..

In order to freeze around the area to be mined one must first calculate the heat loss load to size the equipment..a virtual impossible task as all factors are only guesstimates ..so it is done by staggering units and designing the system to be modular (Need more ..add more).

There are so many unknowns ..for instance what type of soil or rock are we attempting to freeze..??

That varies..sand and clay have different properties(Heat load co-efficient s) to calculate heat loss load estimates..

Rock is different again..so imagine how far down ..how many different materials we are trying to freeze and you have some idea of the problem..

We are just starting here..

But mining uranium has an unique little problem..U3O8 as it decays creates Heat..!!

So the richer the ore the more heat is generated !!

McAurther River high grade areas in the 20%+++ U3O8Range may be 25-35 Deg C 1000 feet underground..Or more..

That heat has to be removed before the ground can be frozen although the ore body itself would not be frozen..just the area of soil and rock that is NOT going to be mined..BUT that heat is transferred through the ground..as BTU's(Heat)moves from hot spots to cooler spots..(One of the rules of heat transfer physics..)

Then there is the ammonia plant..or staggered Plants..must be attended by a licensed engineer or qualified person around the clock and kept running 24-7 forever..or until all the ore is mined..

The ammonia plant was started in McArthur River in '99 and is still running..

(We discussed this here on the KXL board years ago and it never hurts to refresh the topic ..)Having traveled extensively through Northern Sask.as a past resident there for 11 years ,I can tell you that Northern Sask. has more jack-pine sand..muskeg..lakes .. and all sorts of swamp than they have southern Prairie..

Our chances of being in the same boat for mine flooding is a real risk..and more than possible..

if we get that far..

But y'all can read about the process at McArthur River here..

I enjoyed it but understand the technical aspects //.it is interesting to follow the charts and see how long it took to get the ground frozen ,according to the charts..months and months..!!

Take a boo and enjoy some Sunday reading..

http://www.cubex.net/Library/Media/Artificial_Ground_Freezing.pdf

Portee

Here is a little history on the process..

WELCOME TO GROUNDFREEZING

Ground freezing is a technique that has been used extensively for groundwater control and excavation support in the underground construction industry for over 100 years. The process involves the circulation of a refrigerated coolant through a series of subsurface pipes to convert soil water to ice, creating a strong watertight material. The material is so strong, in fact, that it is routinely used as the only method of groundwater control and soil support for the construction of shafts hundreds of feet into water-bearing soils. Most ground freezing systems are quite similar in principal. The single most important co mponent of a ground freezing system is the subsurface refrigeration system, consisting of a series of refrigeration pipes installed with various drilling techniques. Depending upon the application, the coolant can be brought to temperatures well below -150 degrees celcius. Ground freezing can be achieved by using either a large portable refrigeration plant or liquid nitrogen. After the initial freezing has been completed and the frozen barrier is in place, the required refrigeration capacity is significantly reduced to maintain the frozen barrier.