Saturday, March 18, 2017

Mining in the Landfills

About 10 years ago, I heard an astonishing fact.  I was told the richest copper deposit in the world is the wiring that has been added to New York City.  Whether or not that's still true (or was ever true), it brings about an important point: our extraction of materials by mining, refining and manufacturing also includes putting those materials back into environments by landfills.  Landfills and junk yards have higher purity iron ore, copper, tin, and a bunch of other metals than you'll find in a typical mine.  To me, a sure sign that some industrial metal is getting rare is that companies will want to mine old landfills. 

Today, I learned that those discarded metals and other things are combining into new minerals
A mineral called Simonkolleite, a corrosion product of Zinc.
[S]imonkolleite, was described as a new mineral in 1985 for samples collected at Richelsdorf, Germany. It is a rare secondary mineral formed by weathering of zinc-bearing slag, and is associated with native zinc, 
Maybe I'm a bit sensitive to it, but the linked article on Science Alert seems to have a bit of a greenie-inspired "mankind is destroying the world" tone to it (IMO, of course).  The geologist they talk to says that since the industrial revolution, we've seen the creation of the largest number of minerals in the shortest period of time in history.
"This is a spike of mineral novelty that is so rapid - most of it in the last 200 years, compared to the 4.5-billion-year history of Earth. There is nothing like it in Earth's history," one of the team, Robert Hazen from the Carnegie Institution for Science told The Guardian
On the other hand, Hazen followed that statement up with an argument that strikes me as rather weak.  He said he and his team analyzed the 5,208 minerals on Earth that are officially recognized by the International Mineralogical Association, and found that 208 of them would not exist if it weren't for human activity.  208 out 5208 (4%) in 200 years is the most dramatic creation in history?  Previously, the most dramatic period of mineral creation was when oxygen was introduced into the atmosphere (a period known as The Great Oxygenation Event).  That event led to an increase in the number of minerals on the surface from just over 2,000 varieties to more than 4,000, essentially doubling.  That's a far cry from 4%.

Most of the 208 minerals triggered by humanity came about thanks to mining, while six were found on the walls of smelters, three in a geothermal piping system, and four on prehistoric sacrificial burning sites in the Austrian mountains.

Many other new minerals could also be forming in our giant waste dumps, encrusting old batteries and electrical appliances like never before, the team suggests.

"There are probably all sorts of things forming as a result of old silicon chips or batteries," Hazen told Chelsea Whyte from New Scientist.

"TVs have all these exotic phosphors they use, and magnets and all sorts of high-tech materials. When you start hydrating and oxidising them, you're going to start finding a lot of exotic new materials."
The point of the article, instead of pointing out that things like this are going to be mined in landfills in the future, is that this "rapid" formation of minerals marks a new period in the earth's history, the Anthropocene.  Clearly, Hazen is an advocate for that explanation:
"That's really I think the most important factor in deciding whether or not the Anthropocene is a new geological time period - the fact that we have created these materials, these crystals, that are incredibly diverse and beautiful and they persist through billions of years," Hazen told Nicola Davis at The Guardian.
 After the fall of the iron curtain, and the arrival of pollution control in former "Eastern Bloc" countries, a new mineral made the scene among crystal and gem collectors.  Called Zincite, it was zinc oxide, ZnO, something that occurs in places like Franklin, New Jersey, but it's virtually never seen in the size and clarity of a new crop of specimens coming from Poland.  The Polish zincites were deep red, sometimes yellow, or yellow to orange, and typically long, prismatic crystals.  It turned out they were collected from the smoke stacks of zinc smelters, and obtained the size and beauty they displayed only because of the conditions in the smoke stack.
Is Zincite a naturally occurring mineral or an Anthropogenic mineral?  Certainly natural because it's found in deposits of zinc ore, just rarely that big and pure.  And that's the heartburn I have with this insistence on "Anthropocene minerals".  Consider the first picture, that Simonkolleite, which is another zinc compound (zinc chloride hydroxide monohydrate).  Calling it a man made mineral is simply saying we've never seen it before, but have we really examined every microscopic particle of grit from every zinc deposit?  Most Zincite deposits are small crystals.  Is it really new, or is it just an unusual occurrence?  Can we ever really know? Likewise they talk about abhurite, which was found on the wreck of the SS Cheerful, which sank off the coast of Cornwall, England in 1885, and only formed because of a chemical reaction between the salt water and the ship's sunken supply of tin ingots.  Given the right constituents, this could have formed anywhere. 

I have to say it's interesting, but I'm not sure I'm convinced. 


  1. Over time, most of these "novel minerals" will probably be subject to normal weathering and and altering. Ordinary ore deposits are the most stable end point of these processes. When I pulled colorful crystals out of the tanks used to etch transformer cores (silicon steel), I never thought of them as a new mineral.

  2. One man's trash... One day, the landfill will be a goldmine of wealth producing raw materials.

    1. And unless towns are really slipshod with their record keeping, we know exactly where they are.