ISR Mining of uranium – Explanation of the new method


ISR uranium is responsible for almost all uranium mines in the United States (except for recycling through phosphates). More than 20% of global uranium mining is now coming from the in situ method, mainly through In Situ Leach (ISL) mining in Kazakhstan and Australia.

Due to the large number of ISRs of uranium projects on the horizon over the next ten years, as in the United States, Kazakhstan and Australia, the in situ (ISR) uranium method will allow US and global utility companies a tens of millions of pounds of newly-built uranium by 2020.

We discussed the basics of ISR uranium exploitation with Bill Boberg, executive director of UR-Energy, whose company plans to mine uranium Wyoming's Lost Creek and Lost Soldier method in situ of the uranium mining method. the questions our readers wanted more information.

StockInterview: How did the uranus actually enter the sandstone and become a front deposit?

Bill Boberg: Natural processes have led to the deposit of uranium in the aquifer. Uranium was deposited with naturally occurring underground water when natural oxygen in groundwater was exhausted due to natural chemical reactions with minerals and organic material contained in the aquifer's sand. Uranus is still transmitted by underground water flowing to deposits. Liquid groundwater also naturally rinses the parts of the deposit and deposits it again at a short distance. This is a very common natural process that happens in many aquifers.

StockInterview: When you are mining the ISR method, do you destroy or contaminate the aquifer where you are mining?

Bill Boberg: There are probably thousands of uranium sites around the world of varying quality in sandstones, which are also aquifers. Only a few hundred of them will contain enough uranium that will eventually be mined. There, even if it is mined, most of the uranium that was in the aquifer will be removed from the aquifer instead of staying there. The in-situ mining process (ISR) simply turns the natural process that has put uranium there. It's a really simple process. The restoration process, after completion of mining, actually returns the aquifer back to its pre-mining conditions. There is no way the aquifer is contaminated or destroyed (ISR mining).

StockInterview: Many ecologists claim that the removal of uranium changes the aquifers. Is the aquifer significantly different than before the mining occurred?

Bill Boberg: Probably not very different. The formation of uranium deposits in sandstones is the result of oxygen groundwater that came from the surface, carrying uranium that settles when oxygen is exhausted or finally exhausted. The deposit is in place in the sandstone. As fresh oxygen goes down to that point, uranium will again be dissolved.

StockInterview: How do you know where the deposit is for the injection of fresh oxygen?

Bill Boberg: On one side of the deposit is what we call a modified or oxidized sand. On the underside of the deposit there is a reduced sand. There is no oxygen in these sands. Every liquid that transports uranium in reduced sand will consume oxygen and will immediately deposit uranium with natural processes. The mining process adds oxygen to the ore in the deposit itself to allow uranium to go to the solution. It can then be pumped to the surface. The area of ​​reduced sand located downstream of the deposit still exists. It is a contact between altered or oxidized sand and reduced sand that causes the uranium deposition in the sand itself. As the natural flow of groundwater transfers uranium to reduced sand, natural processes will cause deposition of uranium from groundwater if there are some that do not pump onto the surface and recover during mining work.

StockInterview: How do you control the flow of water during the ISR extraction process?

Bill Boberg: The flow of the fluid is controlled by pumping the production well at a faster rate than injectable injectors that inject fluid. In other words, we create a flow into the production well as it pumps at a faster rate than the fluid is pumped into the surrounding injection wells. In this way, we end up with a certain amount of 'bleeding'. Most of the groundwater regularly returns to the aquifer. About half a percent of the water used in the system is actually "bleeding" because we pump a higher rate at production bores – between half and one percent higher than the one we inject. So we control the flow from the wells to inject into the wells.

StockInterview: What is the solution that will be used during the ISR process in Wyoming?

Bill Boberg: This will be an alkaline solution – basically just adding carbonates and oxygen to normal groundwater. The carbonate can be in the form of a simple sodium bicarbonate or carbon dioxide itself. The solution used is described as not much different than Perrier® water. The solution is not something that is outside the area of ​​normal groundwater and would not cause anyone any problem. The combination of carbon dioxide or bicarbonate of sodium and oxygen in groundwater is indeed a fairly benign solution. But, it sufficiently changes the chemical character that causes uranium to enter the solution. It's actually just a reversal of the process that led to uranium uranium. Uranium is deposited in the & quot; reduced form & quot ;. The alkaline solution only reverses the deposit-making process using water already in the deposit. Adding oxygen allows uranium to enter the solution and then lift it to the surface. There, the uranium is removed on a polycarbonate resin in the ion exchange column.

Interview with warehouse: But other areas of the world, such as Kazakhstan, rely on sulfuric acid in the in-situ recovery method of uranium.

Bill Boberg: Sulfuric acid will not be used as part of the in situ process. Sandstone deposits in the Wyoming region are very suitable for mining in the alkaline species. The use of acid for in-situ mining is considered suitable only under certain geological conditions, especially in areas with very poor water quality. Where we have good water quality in the areas of Wyoming, where we are mining, alkaline is far more convenient means in situ mining. Using alkali is much easier to clean and then restore the aquifer. Acids can react to many things except uranium. They can dissolve pyrite, sulphides and other minerals in the sandstone. Acid can free many more unwanted things in formations that can make it difficult, in some cases, to recover uranium and make it difficult to work properly. The alkaline process is a much cleaner process, and it is much easier to restore the aquifer.

StockInterview: Tell us about building an ISR field for uranium mining.

Bill Boberg: Wells are installed similarly to the most common wells – with PVC pipes. The PVC casing would be cemented in place, and then pipes similar to that for irrigation would be used to transport water to the well for injection. Similar pipelines take the same water, exiting from the production well, when moving it to the ion exchange column. When you get to it, this is essentially a water plant. You are dealing with pipelines and water and oxygen and bicarbonate of soda. There is not much that would cause anyone a problem.

StockInterview: There is concern about the use of water in certain parts of the United States. Will your company consume large amounts of water when digging in Lost Creek or Lost Soldier?

Bill Boberg: Consumption will be very low because in-situ mining is basically a closed process. We use groundwater found in the uranium deposit itself. We pummel it. Let's get it to the surface. We charge it with oxygen and sodium bicarbonate. Then we go back through the formation. Ninety-nine percent or more of the water remains in the formation. We just have to get out and throw half to one percent of the water we produce.

StockInterview: While ISR mining, how does your company ensure that radiation does not escape from the aquifer and contaminates people from groundwater or a beverage for livestock?

Bill Boberg: The key is a very comprehensive monitoring program through a borehole monitoring system. They surround the fields of the well. Shallow wells for monitoring are supervised by any overhead aquifer of drinking water. Wells for the monitor are very close to the field of the well. The mining process is pumped at such a speed that it leads to the flow to the production wells themselves. This ensures that the flow of groundwater does not move the mining solution from the production wells. From the point of view of the mining company, that would be a huge loss if we could not control the fluids. We would have a huge cost in the inability of the liquid to go where we want. As a result, we carefully set up the process to make sure that the fluids move as we need them. The wells for the monitor help us to know that we have control over the flow of water. Monitoring wells also help the state government and the Nuclear Regulatory Commission to ensure that our fluid flow is under control.

StockInterview: What happens when the ringtones turn off or the alarm sounds on the screens?

Bill Boberg: If any of the wells suggests the potential of mining solutions to get in the vicinity of the monitor, we would immediately stop the injection of solutions and use 'overpumping'. in order to get the solutions back to the mine. Monitor wells are there to ensure we can see what's happening in the area. They are there to enable us to ensure that our operations are working properly. If the solution happens to enter the monitor well, it's not that bad. It tells us that we need to make some corrections and move forward. The control borehole helps us to develop better controls in the natural system we are facing.

StockInterview: How to return water back to quality prior to mining?

Bill Boberg: The aquifer is usually renewed by the reverse osmosis process. This is a super filtration process. We can use other techniques, such as reduction or bio-remediation. But the reverse osmosis is probably the one that would be more commonly used. More than 99 percent of the water used in the mining process is recycled. Returns to the aquifer after returning to the surface. These are only new quantities of recovered water pumped back through the mined area to ensure that they return to pre-mine conditions. Only small amounts of water that remain with higher concentration can either be evaporated or distilled to create solid waste for disposal. Or, they will be taken care of in a licensed landfill.

StockInterview: Can you explain the deep-root process?

Bill Boberg: Deeply Disposal is an activity that is strictly licensed and controlled by States. It's not just about when the mining activity is over, but probably something that will be used during mining activities. This means: waste water is injected into a very deep stone unit. The well for disposal is too deep and with such poor water quality that it could never be used for drinking water. These wells are usually 6,000 or more feet deep. The quality of the deep stone retaining must be able to retain the deposited water without the potential for leaking into other rock units. This is a common and well-accepted method for the disposal of liquids. It is strictly licensed and supervised. We are currently evaluating both our project areas through the use of old wood logs for oil and gas, in the area for rock units that could be favorable for deep wells. As I have already said, a deep well for disposal is a small percentage of the total amount of water to be processed.

StockInterview: How can ecologists be convinced that water will be returned to their pre-mining conditions?

Bill Boberg: Wyoming and Nebraska have a similar law, which requires a 100 percent link to the complaint. Bonds are a result of the calculation, depending on the different quality of deposits and the way they will be mined, which determines how much the state would cost the restoration if the company went bankrupt or could no longer work in the reconstruction of the mine. It is a complete 100% pre-determined link. This is probably in the range of several tens of millions of dollars, which would be needed to connect.

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