Hi Mate,
The difference between the 2 Ce figures is such that one is the head grade, the other is the post-processed (concentrate) grade.
Ce, La recovers at lesser extent than the high value elements and hence the composition of the basket is not the same post processing.
Note the below is on the SS feed grade and not the 650ppm for the 315mT total resource grade but the principle is the same. Have highlighted the below in red.
View attachment 3608336http://www.hochschildmining.com/resources/1955/CMD Investor Presentation_FINAL.pdfThere some detail regarding the low/lack of radioactive material produced in the processing of ionic clays above as well as some of these other links.
"▪Carbonates produced at the plant’s expected conditions are classified as “Exempt” according to the International Atomic Agency (IAA) for transport and for bulk handling
▪ Radioactivity tests by ANSTO included activity concentration analysis for Thorium230/232/228, Uranium-238/235, Radium-226/228, Lead-210, Actinium-227, Potassium-40 and Samarium-147"
https://pubs.usgs.gov/pp/1802/o/pp1802o.pdfhttps://www.nature.com/articles/s41467-020-17801-5https://pubs.usgs.gov/pp/1802/o/pp1802o.pdfIXR have also stated that there is 'no radionuclides', i'm again assuming it's in reference to the concentrate.
My understanding is that these are essentially precipitated prior and not concentrated to ppm levels which are any greater than the ppm in ground content. Just as the levels in feed stock are not at dangerous levels.
https://ionicre.com.au/wp-content/uploads/2020/12/200916-IonicRE-Presenting-at-REE-V-Con.pdfView attachment 3608441The main difference I suppose between ionic clays and hard rock, is that a high grade ppm of U and Th (which are at elevated levels in the feedstock) means that post processing the tailings are at that same high grade.
https://inis.iaea.org/collection/NCLCollectionStore/_Public/49/034/49034222.pdfAlso worth noting that not all uranium is the same and essentially the more aggressive you process it, the more radioactive it can become. This is why hardrock projects have a greater issue with radionuclides irrespective of the physical quantity bein processed.
https://www.epa.gov/radiation/radionuclide-basics-uraniumYou essentially have 2 options; dilute it down to lower levels and/or it's stored in a closed loop system.
My understanding is that the U and Th for IXR is removed in the primary leach (i.e still at a low ppm value) thus never getting to dangerous levels that you would see in the hard rock space.
https://www.mdpi.com/2075-4701/10/11/1524/pdf"Among various gangues, radioactive elements are a serious challenge in the REE production process, regarding specific regulations for safety management in the processing units (for more details refer to [17–19]). Thorium (Th) and uranium (U) are naturally occurring radioactive materials (NORM), which can be found in the REE deposits (Table 1). Monazite and xenotime are the most known REE-bearing minerals that contain radioactive elements. For instance, the REE-bearing ore at Mountain Pass, i.e., a major bastnäsite resource in California with rare earth oxides (REO) of 8.5 wt.%, contains thorium (Th) and uranium (U) of 0.02, and 0.002 wt.%, respectively [19].
In addition, the Bayan Obo bastnäsite and monazite deposit in China contains minerals such as fluorite, magnetite, barite, calcite and quartz with magnetic susceptibility, specific gravity, electrical conductivity, or floatability similar to REE-bearing minerals [20,21].
The low concentration of radioactive elements in the upstream rare earth ore processing units, e.g., in physical beneficiation, results in quite low emission of radioactivity, whereas the higher concentration of the radioactive elements in downstream separation lines requires safety measurements to be carefully considered.
For example, an exposure of a worker to an ore containing 500 ppm thorium and 50 ppm uranium, staying 1 m away from a large mass of the ore for an entire working year, leads to a total exposure of 2.4 mSv that is below the dose limit for a NORM worker, 20 mSv [17]. This exposure is mainly caused by ore dust inhalation (at 1 mg/m3 ) and incidentally ore ingestion (at 100 mg/day)."
You can view the SS for detail relating to the process circuit which should help with interpretation to the above.
The environmental issues that have plagued most relates more to the fact that they didn't use heap leaching and or the tailings weren't closed loop or the tailings weren't treated.
IXR is working with ANSTO on the heap leaching program as well as ALS. I garner that the stage 2 met testing may have some more of the detail you're after. Note that one of the main reasons the operational costs weren't as low in comparison to some of the chinese was introducing membrane technology as part of the water balance treatment.
"The inclusion of membrane technology is seen as a significant step change from historical IAC processing flowsheets operating in southern China, where illegal and unregulated mining of such deposits has resulted in considerable environmental damage."
In summary to you're question; It's my understanding that the radionuclides/deleterious elements are not concentrated to the same level as the REO as they are removed in the first stages of processing. (primary leach/pregnant leach solution.
Thus the ppm values are much much lower and likely low enough to be treated as NORM. This is supported by a few ionic clay development projects essentially stating the same. No/Low radionuclide process. (Biolantanidos (now aclara), tantalus, IXR etc).
View attachment 3608660Hope that answers your question, IXR might have more detail that me. Tim is a metallurgist after-all i'm assuming the lack of detail is such that the process is quite arbitrary but potentially they can be more explicit with detailing why it isn't a problem.
SF2TH
(20min delay)