Tuesday, August 18, 2015

No amount of gold can put Humpty Dumpty together again

Remember the Second Law of Thermodynamics from the high school days?  What? You forgot that already?  No way!

The next time you read about, or see something, which makes you comment along the lines of "the world is getting more and more chaotic," remind yourself about the second law of thermodynamics, according to which the amount of disorder in the universe will always increase.  Always.

Did that stir any memories of your high school science classes?  You recall that entropy is a measure of the level of disorder?  What? You forgot that already?  No way!

I have been thinking about the disorder and entropy a lot more after reading about two incidents, one here in the US and another in China.  Here, it was that awful accident that turned a river yellow; I am sure you saw plenty of photos of that.  And in China, it was the explosion at Tianjin.

These, like many events that unfold in life, are irreversible.  We can't undo them.  Once the egg falls and cracks, all the king's horses and all the king's men cannot put Humpty together again.  In irreversible processes, entropy always increases.

Mining is one of the best (worst?) examples of entropy, where we can also see that Humpty Dumpty cannot ever be put together again once we start digging down. The Animas River turning mustard yellow reminds us about one of those uncomfortable and inconvenient truths about mining:
The accident heightened a debate here over the future of this region’s old mines, and served as a reminder, some critics say, that the Gold King’s toxic demise could be repeated at any of thousands of abandoned mines around the country.

We humans value gold, for reasons that are beyond my wildest imaginations.  Thus, we mine for it.
In its heyday, the Gold King produced about 350,000 ounces of high-grade gold, according to its current owner, and its products landed on the fingers of well-off women in New York City, in the pockets of everyday Americans and in the vaults of banks around the world.
So, what is the connection with the explosion at Tianjin?  Mining for gold.  Cyanide is the connection:
Alarming levels of sodium cyanide have been found at wastewater monitoring stations in the disaster-stricken city of Tianjin almost five days after a series of deadly explosions claimed at least 114 lives and sparked intense criticism of the Chinese government.

How does cyanide connect Tianjin and the Animas River spill?  The spill was from an abandoned gold mine.  And one of the most common uses of sodium cyanide is in the mining of gold.
Most of the world’s gold is not found in nugget form but as very fine gold powders in rocks. In fact, our cultural demand for gold forces us to mine in rocks that can be as low as 0.005% gold. This means we need industrial extraction to separate and purify gold from all the other materials.
After mining and milling, the crude rock mixture is turned into a fine powder and added to a solution of sodium cyanide. The gold forms strong bonds with cyanide molecules and can then be separated from the rest of the minerals because it is then soluble in water. It then reacts with zinc and turns back into a solid. Finally is smelted to isolate the gold and cast into bars.
Mining for gold is perhaps one of the most toxic mining activities ever.  Is our madness for gold worth all this disorder?  I suppose we need to send people back to the science classes and not let them out unless and until they have understood the second law of thermodynamics and entropy!

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