Crash Course Chapter 23: The Environment: Depleting Resources

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Transcript

When we wander over to the third E in this story – the Environment - we note two things: both the increasing demand of exponentially more resources being extracted from the ground and exponentially more waste being put back into various ecosystems.

Because we are trying to assess here whether we can justify ever-increasing amounts of money and debt, for now let's just concern ourselves with the resources we take from the natural world to support our global economy.

Oil is not the only essential resource that is fast becoming more expensive to produce, harder to find, or both. In fact, we see an alarming number of examples depletion of critical resources that almost exactly mirror the oil story.

First we went after the easy and or high quality stuff, then the progressively trickier, deeper and or more dilute stuff.

Here’s one of them.

When we first came to this country, we were finding some pretty spectacular things just lying around, Add image like this copper nugget. Soon those were all gone, and then we were onto smaller nuggets, and then onto copper ores that had the highest concentrations.

Now?

Now we have things like the Bingham Canyon mine in Utah. It is two and a half miles across and three-fourths of a mile deep, and it started out as a mountain. It sports a final ore concentration of 0.2%. Do you think we’d have gone to this effort if there were still massive copper nuggets lying around in stream beds? No way.

Let’s take a closer look. See that truck way down there? It’s fueled by petroleum; diesel, specifically. If we couldn’t spare the fuel to run that truck, what do you suppose we’d carry the ore out with? Donkeys? These trucks carry 255 tons/ per load. Suppose a donkey could carry 150 lbs. This means this truck carries the same in a single load as 3,400 donkeys. That’s quite a lot of donkeys.

My point here is that a hole in the ground a couple miles across and three fourths of a mile deep is a pretty spectacular display of the use of energy. Again, instead of seeing a really big hole, I invite you to look past that and think of how much energy it took to make that hole.  When energy begins to get scarce, it seems unlikely to me that we’ll be digging too many more holes like this one, which means we'll be taking less copper out of the earth to support our desire for an ever expanding economy..

Now here’s where the concept gets interesting. The amount of energy and money that is required to extract any mineral or metal is a function of the ore grade. We would measure that as the percent of the ore that consists of the desired substance. So a 10% copper ore, for example, would consist of 10% copper and 90%, uh, other stuff that's not copper. If we plot out how much other stuff we have to extract and then dispose of in pursuit of our desired substance, we get a chart that looks like this. Look familiar to you yet? It should; it’s a non-linear  chart.

It tells us that if we had an ore body with only 0.2% copper in it, we’d need to mine 500 pounds of ore in order to extract one pound of copper. I used this particular value because that happens to be the concentration of the Bingham Canyon mine. This helps to explain why this hole is so big. It tells us that without these giant trucks, we probably wouldn’t be mining such low ore grades. It means that we are already on the far right edge of the bell curve, in terms of energy and cost.

Do we do this because we like the challenge of low ore grades? No, we do it because we’ve already high-graded all the other known ore bodies, and this is what we are down to. We do it because it is the best option left. We do it because, after only 200 years of pursuing an industrial economy, we’ve already burned through all the better grades.

The story here is that we, as a species, all over the globe, have already mined the richest ores, found the easiest energy sources, and farmed the richest soils that our Environment has to offer.

I *could* easily fill hours of more video with additional alarming examples of resource depletion; but the bottom line is this: We have taken several hundreds of millions of years of natural ore body, fossil energy deposition, aquifer accumulation, soil creation, and animal population growth -- and largely burned through them in the few years since oil was discovered. It is safe to say that in human terms, once these are gone, man, they’re gone.

So, if we are getting less and less net energy for our efforts, and the other basic resources we need to support exponential economic growth are requiring a lot more energy to extract because they are depleting, then does it make sense to keep piling up exponentially more money and debt? Isn't it just common sense to observe that money and debt have to exist in some sort of relationship and proportion to primary and secondary wealth?  

Comments

billhopen's picture
billhopen
Status: Member (Offline)
Joined: Sep 9 2009
Posts: 11
bingham canyon mine, depleted ore grade

There are 400,000 ozs of gold, 4 million oz of silver, 25 million pounds of Molybdenum that come out of this pit mine ore body that also help to make this mine profitable.....but yeah .2% ore for copper is crazy,  besides the 500# of ore waste per pound of copper, they must keep the pit perpetually pumped free of water, or it will turn into a toxic lake, like the large pit mine in Butte Montana.

It takes something like a 40 mile long up hill grade by diesel burning truck round and round to get the ore out of the hole.  Copper is under $3.00 per pound, diesel 3.00/gal....I don't know how they make the energy math work, all that rock must be crushed, pulverized, mixed into a slurry with water, then the copper powder purified by electricity and melted and poured into ingots....whew...their margins must be so thin.

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