Water plays an integral role for In Situ Recovery (ISR) uranium mining. If the water is not in the right place, ISR mining can not take place. A company’s ‘pounds in the ground’ are nearly worthless or may have to be extracted through other means.
One of the purposes of the Advanced ISR series is to finally bury the misleading ‘Pounds in the Ground’ mantra. Some uranium companies have given the wrong impression about their resource estimates by championing the number of their historical pounds. Some of those pounds might never be mined or even permitted for mining. Having NI 43-101 compliant resources does not necessarily confirm whether companies have economic deposits in which the extraction process can take place. Water could be the issue.
Our interview with Glenn Catchpole of Uranerz Energy explains what investors should know about water’s role in ISR uranium mining. Companies with an ISR project may disappoint shareholders because of the water location, or lack of water, in relation to the ore body. Many analysts have assigned values to an ore body without taking water into consideration. We hope this interview will help shed new light on these valuations.
StockInterview: Let’s start with the basics. What is the first requirement for an In Situ Recovery uranium mine?
Glenn Catchpole: The uranium ore body itself must or should be in a confined aquifer. What you are looking for is that the uranium-mineralized sandstone is in this aquifer. If there’s no water in the formation and it’s dry, then you can’t solution mine (also known as ISR).
StockInterview: What do you mean by a confined aquifer?
Glenn Catchpole: A confined aquifer is one that is confined between two impermeable geologic strata. In Wyoming, typically they would be either mud, stone, shale or some type of clay which forms an impermeable barrier above and below the sandstone hosting the uranium. Over time, water has moved down the sandstone strata. As it moves, the water comes under pressure and becomes confined.
StockInterview: Why is this important?
Glenn Catchpole: If you complete a water well in a sandstone strata that is under pressure and encase it in cement, the water will actually rise in that casing to some level based on the pressure in the aquifer. In some cases, there could be enough pressure or ‘head, ’ where the well will actually flow onto the surface on its own. You want the water under pressure because the more pressure in the formation, or in the sandstone unit, then the more oxygen you can put in the solution. In the United States, you either add CO2 or sodium bicarbonate plus an oxidant, such as oxygen, to the groundwater. Then you re-inject the solution into the sandstone host formation to dissolve the uranium off the sandstone. The more oxygen you can put into the solution, the more effectively you can dissolve or oxidize the uranium.
StockInterview: How do you find out how much pressure you have in the aquifer?
Glenn Catchpole: Let’s assume you’ve got good uranium values from the results of your exploration program, and that you may have an economic ore body using the ISR method. You then need to confirm that the ore body is in an aquifer or that the sandstone is saturated with water. To do that, you would install hydrologic testing wells. Assuming there is water in those wells, you would then do a pump test to determine the hydrologic properties of this aquifer.
StockInterview: How do you know if your properties have mineralized sandstone formations which are saturated with water?
Glenn Catchpole: There are deposits in Wyoming that are good in terms of grade, but they are completely above the water table. They are not saturated. In our case, we focused our acquisition activities in the Powder River Basin, which we know from our previous work. Most of those sands that are hosting uranium are indeed saturated with water. There are some that are not. From our experience we pretty much know those deposits that may be sitting above the water table. In other words, they are not saturated with water. If uranium went to $500/pound, maybe some day you could put a conventional mine on them.
StockInterview: What about those in the exploration stage?
Glenn Catchpole: If you were working in a new area doing raw exploration, and you did come across good mineralization that looked like you had an ore body there, you might not know for sure about the hydrology and what the water levels are like. You could get into a situation where either the sandstone is dry, or it is only partially filled with water. Or it’s filled with water, but it doesn’t have much head or pressure on it. You’ve got to do some test work and nail that down.
StockInterview: Is there any way of detecting the problem in advance, before you discover you’ve got an inadequately saturated formation?
Glenn Catchpole: When you are drilling an exploration hole, the driller knows when he encounters any water at all. If he doesn’t get any water, you know right away, you’ve got a problem very early on. When the driller starts out, he can start drilling with air. If he encounters water in his drilling, then he’s going to switch over to drilling mud to carry the cuttings. As he’s drilling a hole, he is creating cuttings. He has to have a mud slurry in order to carry those cuttings out of the hole. An experienced driller will have a good feel for how much water he’s encountered. These drillers have worked all over Wyoming; they’ve got some feel for the local geology and what the water situation might be.
StockInterview: Once you’ve established the saturation and pressure, what’s next on your checklist?
Glenn Catchpole: Assuming the mineralization is not tied up in clay streaks in the sandstone unit, then you want to know the permeability of the aquifer. How readily can you move water through the formation? To do that, you have to do a pump test, or aquifer test to calculate the value of the permeability of that aquifer. The higher the permeability, the more helpful it’s going to be in your mining process. You have to be able to move the solution through the formation in order to leach uranium off the sandstone grains. The more permeable the formation, the more fluid you can move through it; the more effective you can be in extracting uranium.
StockInterview: How do you determine your rate of production?
Glenn Catchpole: Two things determine your ISR mining production rate. That’s the concentration of the uranium in the fluid coming out of your recovery wells and the flow rate. There’s an equation you can use to determine the rate of production in pounds. You multiply your flow rate by your concentration, also known as head grade.
StockInterview: Is this how companies conclude how many pounds they will annually produce on their ISR project?
Glenn Catchpole: Generally, you have a production rate you are trying to achieve. For example, if I want to produce one million pounds per year, and my head grade is 80 milligrams per liter (a typical number used for U. S. projects) and my hydrologist tells me I’ve going to recover 10 gallons per minute, I will need 400 recovery wells. Based upon these hypothetical calculations, I will need 4,000 gallons per minute, or 400 recovery wells each recovering 10 gallons/minute, to produce one million pounds. As a side comment, when people say ‘I’m going to have a solution mine that produces three million pounds per year, ’ it turns out to be a lot of wells. Your major cost in a solution mining operation, once you’ve got the plant built, is putting in your wells. (Editor’s Note: Discussing costs to put in wells with others in the uranium mining sector, we found a range of $20 to $30/foot for each well. )
In a separate information sheet, Glenn Catchpole provided us with a hypothetical approximation of an ISR wellfield in Wyoming. He wrote, “Production at an ISR uranium mine is directly related to the flow rate (FR) coming from the recovery wells and the concentration of the uranium or head grade (HG) in the recovery solution. ”
In this theoretical calculation, Mr. Catchpole assumed a head grade of 65 milligrams per liter, a flow rate of 10 gallons per minute for each recovery well, and an ore body’s average depth below surface of 500 feet. In order to produce one million pounds U3O8, this would require 350 production wells, 420 injection wells and 20 monitor wells. Using these assumptions, the theoretical well field would cost approximately $12 million to construct. Amortized over two years for the life of the well field, the cost for the well field construction – using annual production figures of one million pounds – would be about $6/pound U3O8. By lowering cost/foot for each well, a company could reduce their construction cost to about $4/pound U3O8.
Mr. Catchpole cautioned these are simplistic and very rough approximations of an ISR wellfield cost in Wyoming. He also wrote, “These are presented for illustrative purposes only and the numbers generated should not be used in financial calculations or project evaluations. ”
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James Finch contributes to StockInterview.com and other publications. His focus on the uranium mining and nuclear fuel sector resulted in the widely popular “Investing in the Great Uranium Bull Market, ” which is now available on http://www.stockinterview.com and on http://www.amazon.com