USGS uses machine learning to show large lithium potential in Arkansas

Well I guess this is a good win for short term energy infrastructure, though I'm always pretty torn when its at the cost of ripping open huge swaths of earth to get at the raw material.

It is interesting to see how much of this data could be modelled based on wastewater brines from other industries in the area, assuming we go on to mine the lithium it will say a lot if the ML predictions prove accurate.

One thing I couldn't tell, and its probably just a limitation of how much time I could spend reading the source paper, is what method would be needed to extract the bulk of the lithium expected to be there. If processing brine water is sufficient that may be easier to control externalities than if they have to strip mine and get all the overburden out of the way first.

You physically can't remove the overburden for this. The Smackover is at a depth of multiple kilometers in most of these areas.

It's mining brine. I.e. the "mines" are basically deep water wells.

The limestone itself doesn't have any lithium. It's the water in the pores in the limestone that is relatively concentrated in lithium.

In most of these cases, you're already producing brines from the smackover formation as a part of existing oil and gas production, but the brine is being re-injecting after oil is separated from it. The idea is that it's better to keep those and evaporate them down for lithium production.

That does require large evaporation ponds, generally speaking, but it's not strip mining.

Extremely helpful, thanks for the extra detail here. I have a background in the oil industry and live in a region strip mined for coal (I actually can't tap a useful ground well because of it), but I don't know much about how lithium is actually extracted.

As far as evap ponds go, are there usually chemicals or elements in the same brine water as lithium that is important when evaporating into the atmosphere?

> ripping open huge swaths of earth

Do you have the same trepidation about aluminum, iron, dish soap, and table salt? I ask because the amount of "ripping open" involved in lithium production is like a speck in the eye of a whale compared to all the other mining. In terms of scale all existing and proposed lithium mines are teensy tiny by the standards of mines.

Sure, yes I do wish that we weren't opening such huge holes as we are for aluminum, iron, coal, etc. I worked in the upstream oil industry for a bit and live in an area heavily coal mined, I just wasn't clear how lithium mining compared and didn't want to assume that damage was on the same scale as the others.

It's not even close to as large as the footprint of oil and gas. The Thacker Pass project, which is one of several that are all individually described as satisfying global demand, will ultimately disturb only 7000 acres. Fossil fuel wells usually disturb 5 net acres each, and there are five million such wells in America alone.

I think they're using better processes than evaporation these days. For example, concentrating the brine using reverse osmosis first.

There are a lot of things in deep subsurface brine. It really varies.

First and foremost, here are definitely lots of other salts. It is brine, after all. You produce a lot of halite (salt), gypsum, calcite, and all kinds of other evaporite minerals.

There are all kinds of things in smaller concentrations, though.

What comes out of a oil/water separator would need lots of additional processing before going to something like an evap pond. It's relatively hazardous stuff for a lot of reasons other than oil (e.g. it can be rather radioactive). It typically goes through quite a bit of additional processing unless it's being immediately reinjected.

Those are expensive and are avoided when possible. Brine ponds are cheap if you can use them. But with that said, yeah, evaporation ponds don't work especially well on the Gulf Coast.

The process for here, I was reading, would involve concentration of the lithium with resin absorbers (to separate it from other alkali elements, I imagine), followed by elution into water, reverse osmosis, and only then evaporation. This is called "DLE": Direct Lithium Extraction.

Yeah, underground brine is rarely nice to be around, especially when concentrated, but does often have a lot of useful minerals. Related facts, I’m guessing.

Additionally, that area in Nevada can be - at best - charitably described as moonscape.

Which, for those of us that like moonscape, is a bit sad. But there is a lot of moonscape in that region, and there aren’t a huge number of moonscape fans. At least that are going to try to picket any projects. So overall, meh.

That area of Nevada is also pretty economically ‘challenged’, so why not.

> cost of ripping open huge swaths of earth to get at the raw material.

This mining offsets mining for other things that is happening at several orders of magnitude larger scale. Oil, coal, gas, etc. mining is huge and lithium batteries plus renewables are already reducing the need for those. So, the transition to renewables and batteries might actually result in a net reduction of mining.

Of course doing lithium mining cleanly and responsibly is an important topic. Especially in places close to where people live. But considering the vast amounts of other stuff we mine already at a much larger scale than we'll ever need to mine lithium, this is a drop in the ocean.

And of course the lithium that is mined can be used and recycled over and over again. Once it is in circulation, we'll be re-using it forever. And given the improvements in battery tech, production processes, etc. the amount currently in circulation is likely to power a larger amount of battery capacity when we do recycle it eventually. Even when considering inevitable losses during recycling.

Lithium recycling processes are working fine already of course but there's very little recycling being done at scale for the simple reason that most lithium batteries in use are still very young and quite far away from needing any recycling. If anything, the improved life times of batteries is pushing the date that we need to be recycling at scale further and further away.

Extraction methods very much depend on composition of the deposits and whether they are in brine or other form and what other materials are present. There's a wide variety of brines, rock compositions, clays, etc with some lithium in them.

> ”And of course the lithium that is mined can be used and recycled over and over again. Once it is in circulation, we'll be re-using it forever. And given the improvements in battery tech, production processes, etc. the amount currently in circulation is likely to power a larger amount of battery capacity when we do recycle it eventually. Even when considering inevitable losses during recycling.”

This point is overlooked so often in these discussions. Lithium is not a consumable in batteries, whereas oil / tar / coal etc. is. So, we do some ugly mining for a bit, and then basically stop once we have the lithium we need for use in batteries over and over again. It’s a completely different model than extract-and-burn.

Also, at some point you need to tell people "you don't own this land, so you don't get to say what gets done to it."

I'm half expecting the future more conservative SCOTUS to shoot down land use regulation as a taking, requiring such regulation to be combined with payment for the value lost instead.