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The Importance of Mineralogy

It's been a hectic week of travel through Europe, on behalf of our gold-copper company.

I'm sitting in the Crowne Plaza in Bratislava, Slovakia, getting ready for some meetings in that capacity. The hotel is minutes from the old town, including the church where the monarchs of the Austro-Hungarian empire were crowned. It's an interesting place to say the least.

Slovakia is also interesting for another reason. Uranium.

I'll be spending a little bit of time today reviewing some ideas on that front. As I mentioned on Wednesday, I've been doing a lot of prep research ahead of this. And it's convinced me that one area is incredibly important (and under-appreciated) when it comes to uranium deposits. Mineralogy.

We talk a lot about uranium deposits. But the importance of what form the uranium takes within a deposit seldom gets mentioned.

The majority of deposits hold uranium in the form of uraninite, a uranium oxide. This is the most chemically-stable form of uranium on the planet.

The processing of uraninite is well-understood. Generally, uranium-bearing ore is crushed and grinded, and then uranium is leached with either an acid or alkaline-carbonate solution. Uranium goes into solution and is then precipitated and recovered using ion exchange.

The last parts of this process (solid-liquid separation and solvent extraction) are fairly straight-forward and don't tend to vary much across uranium deposits.

The initial process stage, however, can vary considerably. As with most ores, some rocks are easier (and thus cheaper) to crush and grind. At deposits that require a high degree of crushing, capital costs for the crush/grind circuits can make up 50% of total capex.

This is an especially important point for uranium. As we've discussed in the past, a large percentage of global uranium production comes from fairly low-grade deposits. Meaning that cost-containment becomes very important to running an economic operation.

Here's a critical example. There are a lot of granites on Earth that contain a few hundred parts per million uranium oxide. But only one of them, Rossing in Namibia, produces a significant amount of yellowcake.

A number of factors historically led to the development of Rossing. Low labor costs, political sensitivities, etc.

But unbeknownst to many, mineralogy is a huge part of the Rossing story.
Ore at Rossing requires very little crushing. There's a special reason for this. Mineral grains appear to have been quite brittle. The grains developed sizeable cracks, where uranium was deposited.

These cracks allow leaching fluids to access the uranium and effectively take it up into solution. At most other deposits, the uranium isn't as easy to get at. Thus, more crushing is required, leading to higher costs.

Here's an idea of the difference mineralogy makes in the Rossing case. Because of the fractured character of grains, Rossing ore was originally processed using crushing to "minus 6 mesh". This means ore grains come out of the crushing circuit at a size of 3.36 millimeters.

At many other uranium operations, ore must be crushed to 250 mesh. Representing a size of 0.058 millimeters. This is a 100-factor difference in crushing. It takes a lot of power and equipment to do more crushing work, leading to higher capital and operating costs.

The "Rossing secret" is instructive. When examining low-grade ore deposits as potential development candidates, this kind of mineralogy could be a key. Doing a little bit of thin-section work at the beginning of an exploration program could identify which granites will succeed or fail.

This is not something that typically gets done as part of most exploration programs. It needs to happen more.

By. Dave Forest of Notela Resources

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