Mining And Refining: Fracking

Normally on “Mining and Refining,” we concentrate on the actual material that’s mined and refined. We’ve covered everything from copper to tungsten, with side trips to more unusual materials like sulfur and helium. The idea is to shine a spotlight on the geology and chemistry of the material while concentrating on the different technologies needed to exploit often very rare or low-concentration deposits and bring them to market.

This time, though, we’re going to take a look at not a specific resource, but a technique: fracking. Hydraulic fracturing is very much in the news lately for its potential environmental impact, both in terms of its immediate effects on groundwater quality and for its perpetuation of our dependence on fossil fuels. Understanding what fracking is and how it works is key to being able to assess the risks and benefits of its use. There’s also the fact that like many engineering processes carried out on a massive scale, there are a lot of interesting things going on with fracking that are worth exploring in their own right.
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Mining And Refining: Uranium And Plutonium

When I was a kid we used to go to a place we just called “The Book Barn.” It was pretty descriptive, as it was just a barn filled with old books. It smelled pretty much like you’d expect a barn filled with old books to smell, and it was a fantastic place to browse — all of the charm of an old library with none of the organization. On one visit I found a stack of old magazines, including a couple of Popular Mechanics from the late 1940s. The cover art always looked like pulp science fiction, with a pipe-smoking father coming home from work to his suburban home in a flying car.

But the issue that caught my eye had a cover showing a couple of rugged men in a Jeep, bouncing around the desert with a Geiger counter. “Build your own uranium detector,” the caption implored, suggesting that the next gold rush was underway and that anyone could get in on the action. The world was a much more optimistic place back then, looking forward as it was to a nuclear-powered future with electricity “too cheap to meter.” The fact that sudden death in an expanding ball of radioactive plasma was potentially the other side of that coin never seemed to matter that much; one tends to abstract away realities that are too big to comprehend.

Things are more complicated now, but uranium remains important. Not only is it needed to build new nuclear weapons and maintain the existing stockpile, it’s also an important part of the mix of non-fossil-fuel electricity options we’re going to need going forward. And getting it out of the ground and turned into useful materials, including its radioactive offspring plutonium, is anything but easy.

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Mining And Refining: Tungsten

Our metallurgical history is a little bit like a game of Rock, Paper, Scissors, only without the paper; we’re always looking for something hard enough to cut whatever the current hardest metal is. We started with copper, the first metal to be mined and refined. But then we needed something to cut copper, so we ended up with alloys like bronze, which demanded harder metals like iron, and eventually this arms race of cutting led us to steel, the king of metals.

But even a king needs someone to keep him in check, and while steel can be used to make tools hard enough to cut itself, there’s something even better for the job: tungsten, or more specifically tungsten carbide. We produced almost 120,000 tonnes of tungsten in 2022, much of which was directed to the manufacture of tungsten carbide tooling. Tungsten has the highest melting point known, 3,422 °C, and is an extremely dense, hard, and tough metal. Its properties make it an indispensible industrial metal, and it’s next up in our “Mining and Refining” series.

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Mining And Refining: Graphite

In my teenage years I worked for a couple of summers at a small amusement park as a ride operator. Looking back on it, the whole experience was a lot of fun, although with the minimum wage at $3.37 an hour and being subjected to the fickle New England weather that ranged from freezing rains to heat stroke-inducing tropical swelter, it didn’t seem like it at the time.

One of my assignments, and the one I remember most fondly, was running the bumper cars. Like everything else in the park, the ride was old and worn out, and maintenance was a daily chore. To keep the sheet steel floor of the track from rusting, every morning we had to brush on a coat of graphite “paint”. It was an impossibly messy job — get the least bit of the greasy silver-black goop on your hands, and it was there for the day. And for the first few runs of the day, before the stuff worked into the floor, the excited guests were as likely as not to get their shoes loaded up with the stuff, and since everyone invariably stepped on the seat of the car before sitting on it… well, let’s just say it was easy to spot who just rode the bumper cars from behind, especially with white shorts on.

The properties that made graphite great for bumper cars — slippery, electrically conductive, tenacious, and cheap — are properties that make it a fit with innumerable industrial processes. The stuff turns up everywhere, and it’s becoming increasingly important as the decarbonization of transportation picks up pace. Graphite is amazingly useful stuff and fairly common, but not all that easy to extract and purify. So let’s take a look at what it takes to mine and refine graphite.

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Mining And Refining: Quartz, Both Natural And Synthetic

So far in this series, pretty much every material we’ve covered has had to undergo a significant industrial process to transform it from its natural state to a more useful product. Whether it’s the transformation of bauxite from reddish-brown clay to lustrous aluminum ingots, or squeezing solid sulfur out of oil and natural gas, there haven’t been many examples of commercially useful materials that are taken from the Earth and used in their natural state.

Quartz, though, is at least a partial exception to this rule. Once its unusual electrical properties were understood, crystalline quartz was sent directly from quarries and mines to factories, where they were turned into piezoelectric devices with no chemical transformation whatsoever. The magic of crystal formation had already been done by natural processes; all that was needed was a little slicing and dicing.

As it turns out, though, quartz is so immensely useful for a technological society that there’s no way for the supply of naturally formed crystals to match demand. Like copper before it, which was first discovered in natural metallic deposits that could be fashioned into tools and decorations more or less directly, we would need to discover different sources for quartz and invent chemical transformations to create our own crystals, taking cues from Mother Nature’s recipe book on the way.

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Mining And Refining: Cobalt, The Unfortunately Necessary Metal

The story of humankind is largely a tale of conflict, often brought about by the uneven distribution of resources. For as long as we’ve been down out of the trees, and probably considerably before that too, our ancestors have been struggling to get what they need to survive, as often as not at the expense of another, more fortunate tribe. Food, water, land, it doesn’t matter; if They have it and We don’t, chances are good that there’s going to be a fight.

Few resources are as unevenly distributed across our planet as cobalt is. The metal makes up only a fraction of a percent of the Earth’s crust, and commercially significant concentrations are few and far between, enough so that those who have some often end up at odds with those who need it. And need it we do; what started in antiquity as mainly a rich blue pigment for glass and ceramics has become essential for important industrial alloys, high-power magnets, and the anodes of lithium batteries, among other uses.

Getting access to our limited supply of cobalt and refining it into a useful metal isn’t a trivial process, and unfortunately its outsized importance to technological society forces it into a geopolitical role that has done a lot to add to human misery. Luckily, market forces and new technology are making once-marginal sources viable, which just may help us get the cobalt we need without all the conflict.

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Mining And Refining: Sulfur

When you think of the periodic table, some elements just have a vibe to them that’s completely unscientific, but nonetheless undeniable. Precious metals like gold and silver are obvious examples, associated as they always have been with the wealth of kings. Copper and iron are sturdy working-class metals, each worthy of having entire ages of human industry named after them, with silicon now forming the backbone of our current Information Age. Carbon builds up the chemistry of life itself and fuels almost all human endeavors, and none of us would get very far without oxygen.

But what about sulfur? Nobody seems to think much about poor sulfur, and when they do it tends to be derogatory. Sulfur puts the stink in rotten eggs, threatens us when it spews from the mouths of volcanoes, and can become a deadly threat when used to make gunpowder. Sulfur seems like something more associated with the noxious processes and bleak factories of the early Industrial Revolution, not a component of our modern, high-technology world.

And yet despite its malodorous and low-tech reputation, there are actually few industrial processes that don’t depend on massive amounts of sulfur in some way. Sulfur is a critical ingredient in processes that form the foundation of almost all industry, so its production is usually a matter of national and economic security, which is odd considering that nearly all the sulfur we use is recovered from the waste of other industrial processes.

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