The Anchor House, Inc.

Dr. Anton Chakhmouradian teaches alkaline and carbonatitic systems at the University of Manitoba.  I believe that his research is both top-notch and absolutely critical for the furthering of our understanding of rare earths in various geologic settings. This interview was conducted by submitting questions to Dr. Chakhmouradian which he answered and returned on 3 May 2010.

How complex is the study of REEs compared to base metals or precious metals?

I think, in mineral exploration, every sector targeting a specific type of resource has its own complexities and challenges. The greatest one for people involved REE exploration, be it companies or academics, is the lack of public awareness, at least at the same level that gold, diamond or base-metal exploration sectors are accustomed to.

One can easily strike a bilateral conversation about gold or platinum with a person off the street, but mentioning neodymium or bastnäsite in that conversation will probably draw a blank stare. This, for the lack of a better word, public ignorance ultimately translates into less support for what I do relative to someone working on platinum, for example, even though the economic impact of these different resource types is probably comparable. Besides, there are purely subjective factors at work here, like the historical role of gold as an inflation hedge, which further amplify the differences between exploration for precious metals and rare earths.

On the technical side of things, the stats are fairly self-explanatory. There are over 250 rare-earth minerals out there, but only about 30 minerals that contain essential Au or Pt. (This is not counting the minerals that contain REE or precious metals substituting for other elements.) So, the mineralogical and chemical diversity alone makes REE research a highly specialized area. On the other hand, REE are much more abundant than any of the precious metals, which means they are easier to detect and track down to the source when it comes to geochemical survey, for example. But, by and large, like I said, every mineral exploration sector has its share of problems.

What are some of the misconceptions about exploration for REEs?

There are many misconceptions, most of which stem from ignorance, the point I have made before. Where should I start? Well, just the lack of understanding of what REE are and what they represent geologically is the source of much confusion and misinformation.

High-profile scandals and spectacular failures in some other areas of mineral exploration, that have enjoyed greater visibility and have been publicized to a much greater extent – like the diamond sector, have cultivated a refined and well-informed generation of entrepreneurs and investors. No one in the right mind would support a diamond project targeting basalts or granites. Unfortunately, the REE sector has a long way to go before it reaches the same level of finesse. For example, just recently, I came across a release claiming that assays from some property returned high values of gold, silver, platinum and other rare earths – and that is coming from a company that is supposed to be advising people on their resource investments.

One of the most common misconceptions is that high TREO numbers equal good ore potential. The problem is that many rock-forming and accessory minerals are capable of incorporating REE, sometimes in significant amounts. Suppose you leave your kids $100,000 in the will – a very round number, right? But what if you have ten kids… or twelve? I have seen a number of carbonatites with overall high TREO values, in which REE are dispersed through a dozen different minerals rather than being concentrated in a single “ore” mineral, and none of those dozen would be abundant enough to get anyone’s adrenaline going. This is what many people do not realize: carbonatites and most alkaline rocks are such unusual beasts that enrichment in REE is actually normal for these rocks.

In some geological settings, more than 50% carbonatites contain >3,000 ppm REE. The catch is to find one with a single REE mineral, which would contain REE at economically viable levels. Secondly, that mineral has to be amenable to processing. For example, over 60% of all proven REE reserves in Russia are “locked” in apatite in the huge alkaline intrusions at Kola, which contains up to 80,000 ppm TREO. However, none of those REE are extracted, even from the Khibiny apatite that is mined and processed for phosphate.

Beyond Kola, there are large deposits of REE-bearing apatite in eastern Siberia, southern Mongolia, South Africa and other places, but technologists are yet to prove that nitric acid leaching of phosphate ore is competitive relative to bastnäsite mining. Then there is eudialyte and several other minerals that may potentially serve as a source of REE, but their economic future is yet uncertain.

What possibilities do you see unfolding in rare earth geological research over the next decade?

First of all, I see some major breakthroughs in our understanding of how and where REE concentrate. With the equipment we have at our disposal these days, we can identify any of the common REE minerals in ten seconds by zapping it with a laser beam, and detect any of the REEs in any sample at the sub-ppm level with a micron-scale resolution. Apart from their obvious practical importance (for resource evaluation, metallurgical studies, etc.), these developments enable us to correlate specific types of REE mineralization with specific rock types, geological processes and tectonic settings more accurately than ever before.

Hopefully, we are going to reach the point soon where our cumulative knowledge could be put together into an integrated model for REE deposits based not only on the type of host rock (which is essentially the extent of our current understanding), but also such parameters as mantle dynamics, tectonic regime, paleogeographic factors, etc. For some deposit types, we are only beginning to unravel the complexities of their origin. Secondly, the recent revival of industrial interest in rare earths has given a boost to field-based research in most parts of the world, which has led to, and will undoubtedly lead to more, exciting finds and, perhaps, even discovery of new deposit types. In Manitoba alone, we have described four new carbonatites in the past decade, three of which host REE mineralization.

Where in the world would you look for rare earths?

Carbonatites and alkaline rocks enriched in REE occur in a variety of tectonic settings, and any of them, provided the right climatic conditions, can develop an REE-enriched weathering carapace. This basically means that a rare-earth deposit can be found literally anywhere on any of the six continents.

There are many other factors at play here which will determine whether it is practical to look for a mineral deposit in this particular corner of the world or another. Let’s say, a fortuitous concatenation of circumstances produces a large carbonatite body in a rift setting with primary monazite, apatite and pyrochlore, which then weathers into a thick lateritic carapace hosting millions of tons of REE- and Nb-rich ore ready to be scooped up. But then circumstances take a turn for the worse and the rift is flooded by sea water. Obviously, several hundred meters of marine sediment deposited on top of our REE-Nb deposit will make it difficult to find and greatly diminish its value.

Then, of course, there are all sorts of political, economic and social factors that might attract or, on the contrary, deter potential investors and entrepreneurs should a commercially viable deposit be found, and have to be carefully thought through beforehand. For all these reasons, I would limit my exploration efforts to the well-exposed parts of North America, including both cratons and younger orogenic belts, as well as understudied investor- and mining-friendly countries with diversified geology, such as Kenya.

What has been the biggest surprise in your study of the REEs?

The greatest surprise of all was that no one has so far attempted to look at the “big picture” of REE transport and concentration, or even systematize the existing knowledge in such a way that some general trends and patterns would emerge. We have a better understanding of where and why different rocks containing leucite form than why some carbonatites are REE-rich while others are barely different from marbles, even though leucitic rocks are not nearly as economically important as carbonatites. But this just means that there is a lot of work to be done, so it was a good surprise.

How do you characterize a carbonatite?

I would like to give you an informal definition of carbonatite, if I may, simply because I have not formed a solid and inclusive scientific definition of my own yet, whereas the one given in the dictionary just does not cut it, in my opinion. Here it goes: Carbonatites are the most mineralogically and geochemically extraordinary rocks of diverse origin and often turning up where you least expect them.

What is the biggest challenge to overcome when looking at REE deposits?

I would say the greatest challenge one has to deal with when looking at a potential REE deposit is tying in microscale observations (things like replacement of one REE mineral by another or chemical variations within a single mineral grain) with large-scale parameters such as resource distribution, grade variations, tectonics, etc. Anyone who has seen a typical REE-mineralized rock will understand what I mean. There are exceptions, of course, but these exceptions are mostly among low-grade deposits which can be easily modeled, like the Lovozero loparite horizons, for example.

It takes a team of professionals with decades of cumulative experience to figure out the micro-macro connections and, ultimately, make the right call. Few other mineral commodities present the same range of mineralogical-technological problems as rare earths. For example, palladium refining is probably every bit as tricky as the extraction of individual lanthanides, but the bulk of palladium mining is restricted to magmatic copper-nickel ores and does not have to deal with problems like radioactive byproducts.

What is the most exciting thing going on in REEs today?

The recent revival of interest in rare-earth mineral deposits offers an unprecedented opportunity to advance our understanding of these deposits and beyond. By “beyond” I mean all the things that do not have any direct implications for exploration, but are important for figuring out how the Earth works.

Knowing what controls the distribution and transport of such an important group of elements as REE opens up all sorts of possibilities for studying any igneous, metamorphic or sedimentary system. For example, we have been looking at ways to discriminate true carbonatites from carbonatite look-alikes and come across some really interesting geochemical observations completely overlooked by metamorphic and sedimentary petrologists before us.

The REE boom is also exciting because it brings us to places that we would otherwise not go, and we bring along new research tools that simply were not available to our predecessors decades ago. I am really fortunate to be part of these ongoing activities, and just wish I had more students to handle the increasing amount of workload!

Have you noticed any increased interest in REEs over the past year?

Yes, I think so.  It seems like 2009 was the best year so far in terms of many new companies getting into the game, old properties getting revisited and re-assessed, and new options cropping up, as well. Very few people had heard of Clay Howells or Kutessay before, and now someone will be working on both of these and many others, which is great. It is about time we steal some of the spotlight from PGM and diamonds! Mind you, I am not a business person and therefore cannot comment on how healthy the REE business is at the moment, but my dilettante impression is that it is all going very well.

What advice would you offer to a young geologist who is interested in the rare earths?

The same advice I give to every one of my students: read the literature and follow what other people in this field are doing, and do not limit yourself to technical reports or papers in Economic Geology. Look at papers describing speciation of REE in fluids and chemical variation of specific REE minerals, experimental studies simulating natural systems, explore foreign literature – look at graphs and tables, if you cannot read the language. It can be difficult at first to navigate a maze of technical terms and diagrams, but there is no way all this information can be neatly packaged and spoon-fed to you by your mentor, and most of it is relevant – you just never know when you are going to need it!

Special thanks to Dr. Chakhmouradian for helping me to understand a number of issues regarding the rare earths!