This is our second post in the series on lunar mining and whether or not it makes sense to help bootstrap a new potential resource extraction industry. After all, if there is a new lucrative source of vital materials that would help improve our quality of life, then we, as lunar explorers, ought to help, if not try to found this industry ourselves. Should our rover’s instrument kit be geared towards ore discovery?
Before we can answer that, we need to know what are the normal steps for a terrestrial mine to be opened and generating revenue. There will be significant differences between a terrestrial and lunar mine, but knowing what steps are present, what obstacles need to be overcome, and what hoops must be hopped through here will help us outline the costs for a mine up there.
For the remainder of this post, we will be talking about terrestrial mines and the process therein. The subsequent posts will be about talking about the specifics for refining for platinum group metals and rare earth elements. Then we will discuss what needs to be done for differently for lunar mining and extraction. Finally, we’ll wrap up with whether or not this makes sense to do.
The Terrestrial Methodology
The exploitation of new resources generally has a very standardized methodology. Mining and mineral resource extraction is a very well understood process. People have been doing this for millennia and modern techniques while having undergone evolution have their roots deep in the past. The steps haven’t really changed from the times of the Roman Empire, albeit they have been systematized and thde tails have changed (sometimes radically). Those steps are surveying, proving, extracting, smelting/refining and delivery. Whether those resources are terrestrial, lunar, or otherwise, those steps will remain the same.
Geological surveys are the first step. These often involve geologists trolling all over the areas of interest. They are time consuming and incredibly man-hour intensive. In the past they were complete done on the ground. These days, remote sensing does the general sweep, sometimes from satellite for mineral content, or even aerial. This was recently done in Afghanistan which found a trove of rare earth elements, for example. However, sources that are found must be examined close up and proven to be worthwhile for exploitation.
The next step in finding and exploiting resources is proving that resource. That is that once you have found a site that has a mineralogical content that shows promise to exploit, it has to be examined in detail to verify that the resource is truly worth exploiting. What-if that promising sample you brought back is a single rock with that particular ore combination? You will have to dig a little deeper and provide enough sufficient samples to be sure.
Interestingly, the SEC – Security and Exchange Commission – has established guidelines for all publicly traded companies to prove those resources. One of the SEC's reasons to do this is to prevent some company to pop up, claim to have a site, salted that site, and then disappear after taking investor's money.
The standard for proving a source, as advised by the mining companies that we consulted, is to extract 50 ft to 75 ft (15 m to 22.5m) deep cores for study. Each of these are 22 lbs for every 5 ft (10 kg for every 1.5m) making a single core 220 to 330 lbs (100 kg to 150 kg).
The physical mining part of the process seems relatively straight forward. Once a source has been proven, the ore is removed, often via a surface mine, to a crusher where the ore is smashed into usable and refinable sized pieces. The exact details are dependent on whether or not this is a surface mine or a shaft. Furthermore, this is also somewhat different between the different sorts of metals being extracted as well.
The exact refining process is 100% dependent on the metal being extracted. Since the metals we are discussing here are the Rare Earth Elements (REEs) and Platinum Group Elements (PGMs), we''ll lightly touch on their processes.
Those for Rare Earth Elements are extremely complicated and highly dependent on the source. This is so much the case that it is not possible to take ore from a different mine and use the same processing facilities from an existing mine to refine that ore. This is because of the chemistry of the samples are very, very important. The reason being the extraction process is almost purely a chemical process rather than merely applying a lot of heat to ore. We have been informed that it takes ten to twenty tons of ore to work through the entire process of refining and get the kinks worked out...if there are few problems.
Platinum Group Metals are often extracted as part of a "bundle" of multiple metals that are being pulled out. Nickel, copper, cobalt, gold and iron are often extracted as part of the process. This process is just as complicated as the REE extraction, but not for same reasons. The ore goes through a flotation processes, smelting in an electrical furnace, and then multiple chemical processes. It ought to be noted that there is 1/10 to one kilogram per ton of ore in a good source of PGMs.
Finally, of course, delivery takes place. On earth, the metals are shipped off to customers via truck and train. While the prices are high, Molycorp has publicly stated that the "generic REE" oxide delivered to customer costs $2.77/kg from the Mountain Pass mine.
To Be Continued
Next up we will talk about working this on the Moon. What can be done there? What can be done here? What must be and can be? The process for extracting on the Moon is very similar, yet has serious and interesting limitations. Just what IS doable on the Moon?