A letter to the editor in the current issue of Science: A Uranium Miner's Daughter.

[NNadir]

4. There are a number of leaching agents utilized in these mines.

First off, let me say that we really don't need to mine uranium. What we need to do is to convert existing U-238 already mined to plutonium in fast neutron spectra. All of the breed and burn reactors under late stage development will do this. We can also utilize the mine tailings from the lanthanide mining industry that supports the useless wind and EV industries to extract thorium, and convert it either in thermal or fast neutron settings to U-233.

However, the current nuclear industry does mine and enrich uranium.

Current leaching technologies include these:

Sulfuric acid solutions are one leaching agent, albeit one of which I personally do not approve; it has the advantage of not extracting radium but also has the property of acidifying ground water, which is unacceptable to me. It will also release carbon dioxide from carbonates, not a good thing obviously.

Radium carbonate is also insoluble, and carbonate/oxygen extraction is far more environmentally favorable. The process was discussed recently here: Cai, J., Feng, J., Li, J. et al. Study on scale analysis and synergistic removal behavior of neutral uranium mining hydrometallurgy process. J Radioanal Nucl Chem 328, 991–1000

I'm not sure if the paper is open sourced, so here's an excerpt from the introduction:

Uranium in-situ leaching (ISL) with CO2 + O2 (neutral uranium mining) is currently the most advanced third generation uranium processing technology with supreme cost and environmental protection advantages [1]. In situ leaching uranium is a process integrating mining, beneficiation and water metallurgy. Under the condition of the natural occurrence of the deposit, the prepared chemical reagent is injected into the ore bed through the liquid injection borehole drilled from the surface to the ore bed to react with the minerals and dissolve the uranium in the ore. Then the solution containing uranium is pumped to the surface and sent to the workshop for ion exchange, leaching, precipitation, pressure filtration and drying, finally qualified products are obtained. In the process of uranium extraction, due to the leaching agent (CO32−/HCO3− ) reacts with groundwater (Ca2+/Mg2+) and some components in ore (SiO2, calcium magnesium sulfate and vanadium phosphorus oxide) to form HSiO3−, Fe(OH)3, CaCO3, MgCO3, VO32− and PO42−. With the continuous injection of leaching solution and the increase of CO32− concentration in solution, Ca2+ and Mg2+ are continuously transformed into CaCO3 and MgCO3 precipitation, which will lead to the decrease of permeability in different degrees, blockage of pumping and injection wells, resin poisoning and other problems [2].

Reference 1 is in Chinese, and cannot be called up on Google scholar.

My preference, other than what I will discuss below, would be for supercritical carbon dioxide extraction with a complexing agent like 2-hydroxyisobutyric acid (a natural metabolite in human and animal tissues). A recent example of this approach is here, albeit not connected with mining: J. Deepitha, K.C. Pitchaiah, G. Chandrasekhar, N. Sivaraman, Solubility studies on 2-hydroxyisobutyric acid in supercritical carbon dioxide: Solubility evaluation and application to actinide extraction, Separation and Purification Technology, 2021, 120174.

This would be an ideal technology for use in cleaning up the dangerous natural gas fracking mines in the Marcellus shale in Pennsylvania, which otherwise will be releasing radioactive materials essentially forever. This gas was fracked because the dangerous natural gas industry had a great fig leaf in the solar and wind industries.

If the carbon dioxide is obtained from seawater or air, this constitutes sequestration, some of which will amount to carbonates precipitated as in the Chinese account above.

However, we might consider uranium recovered by removing it from groundwater being pumped to supply irrigation and drinking water. I believe I may have discussed this paper here at one point: Large-Scale Uranium Contamination of Groundwater Resources in India (Rachel M. Coyte, Ratan C. Jain, Sudhir K. Srivastava, Kailash C. Sharma, Abedalrazq Khalil, Lin Ma, and Avner Vengosh Environmental Science & Technology Letters 2018 5 (6), 341-347)

I may have commented on this paper somewhere, if not here, but I am no longer discussing scientific papers here or elsewhere in deep detail.

Were we to place well known amidoxime resins in the line of the water pumps, we would over time collect significant uranium while preventing people from ingesting it. This uranium is NORM, (Naturally Occurring Radioactive Materials)

It is clear that because we did not rapidly expand nuclear energy beginning in the 1990's, after the bugs were cleared, and instead squandered trillions of dollars on solar and wind which did not address climate change, isn't addressing climate change and won't address climate change, our sources of fresh water in many places in the world are drying up.

This leaves the future generations we screwed by our embrace of happy fantasies that didn't work, aren't working and won't work with the requirement to desalinate ocean water, hopefully doing so in such a fashion as to not entirely disrupt salt flows on land and at sea.

The required influx of seawater to desalination plants allows for "mining" the world's largest uranium ore, the ocean, again by placing solid phase extraction agents, including, but not limited to, amidoxime resins within the intake pipes.

However, again, we don't need to mine uranium, dangerous natural gas, dangerous coal, or dangerous petroleum if, and only if, we make full use of the uranium and thorium already mined.