The 366 daily episodes in 2014 were chronological snapshots of earth history, beginning with the Precambrian in January and on to the Cenozoic in December. You can find them all in the index in the right sidebar. In 2015, the daily episodes for each month were assembled into monthly packages, and a few new episodes were posted. Now, the blog/podcast is on a weekly schedule with diverse topics, and the Facebook Page showcases photos on Mineral Monday and Fossil Friday. Thanks for your interest!

Monday, November 27, 2017

Episode 376: US Mineral Dependency

Welcome to the History of the Earth podcast where we discuss all things geological. I’m your host, geologist Dick Gibson. There’s been a long hiatus in my production of this podcast, and I hope to rectify that with some new episodes. Today’s topic for Episode 376 is U.S. mineral dependency.

It’s a common misconception, perhaps an expression of “American exceptionalism,” that the United States is self-sufficient in most or all of the mineral commodities we use in our stuff every day. Nothing could be further from the truth.

In my book, What Things Are Made Of, published in 2011, I documented the uses for everything from arsenic to uranium, and where the U.S. gets its supply of each. At that time the U.S. was self-sufficient, a net exporter, of only 19 of the eighty-plus commodities the U.S. Geological Survey tracks. Today, in 2017 the situation is no better – the count is down to 15 items for which the U.S. is a net exporter.

Some of those items are low-value but interesting things like boron, kyanite, and diatomite. Only three, gold, iron ore, and molybdenum, are high-value metals.

A lot of the mineral commodities we import are obscure, but the vast majority of technologically active Americans use them every day. For example, indium, critical to making flat-panel displays for televisions and computers, is all imported, mostly from Canada and China. Zinc is a well-known metal used mostly in galvanizing iron to prevent rust and in brass and bronze for everything from door knobs to saxophones. In the U.S., 82% of it is imported, mostly from Canada and Mexico.

What about that vital bomb-making element, uranium? Hardly any is used to make bombs in the United States any more, but it helps generate electricity in 61 commercial nuclear power plants across the nation, and almost 20% of our electricity comes from nuclear plants. Where does that uranium come from? Only about 4% of it is mined in the United States. The rest is imported, with Canada and Kazakhstan providing close to half, and Russia, Australia, and Namibia supplying most of the rest.

How about something as common as a flashlight battery? Dry-cell batteries are made with zinc, carbon, and a pasty electrolyte of ammonium chloride and manganese dioxide. All the manganese used in the U.S. is imported, with more than two-thirds of the manganese ore we use coming from Gabon in Central Africa. By far most of the nearly 700,000 tons of manganese the U.S. consumes goes to steel alloys, where it helps make the steel resistant to abrasion and stronger in impacts. That makes it a common alloy in bicycle frames and mining tools.

Or consider common salt. Even though there are 64 plants in 16 states, with Kansas leading the way in production, the United States still imports about a quarter of all the salt we use. About half the salt consumed goes to highway deicing, but a third or so is used to make a wide variety of chemicals, including plastics like polyvinyl chloride or PVC. Food processing and common table salt amount to just 3% of the salt used in the U.S. Chile is the largest source for salt imports, with Canada and Mexico second and third.

The point of my book What Things Are Made Of and this brief set of examples is simply to help you recognize the profound level of globalization that exists in everyday products Americans use.

Thanks for listening, and I hope you’ll join us next time for another episode of the History of the Earth. 

—Richard I. Gibson


  1. Great to hear a new episode!! Thank you!

  2. Very happy to see your great podcast pop up in my feed. Great way to start this rainy Tuesday.

  3. As the others have said--great that you're back, looking forward to more episodes.

    I was interested to read that only 4% of our uranium comes from the US! We were discussing the future of US nuclear a few days ago, and while looking for info, I found one source that said only 200 years to 'peak uranium' ... if true, then not so promising. Does this sound right?

    1. Thanks for the nice words... I'm hopeful I can keep them coming! Uranium 235 is non-renewable and finite, and I've seen guesses of 135 to 200 years for its supply to run out (that would be past peak) using present day technology - and that's the key. There MAY be technological advances that might extend the utility of uranium-based nuclear power indefinitely, but none are in the offing, so far as I can tell. Uranium demand fell noticeably after the Fukushima disaster, but whether that decrease in demand is either big enough, or will be long-lasting enough to affect the overall sustainability of uranium resources, I have no idea.

  4. Glad to hear you back! After my last flight cross country I've been wishing for a Richard Gibson geology tour via Google Earth.

    1. Thanks! Actually back in the olden days (post-audio cassette, early iPod, pre-CD) I really wanted to do something like that. Rent the headset at departure, return at destination. Oh well... :)