Saturday, November 10, 2012

Anthropic influences in the iron cycle

It's been a busy week here at the farm.  We have borrowed our general contractor's heavy trailer, and we've been making use of it and the strength of a co-worker's son to clear out some of the scrap iron that we purchased when we purchased the property.

We acquired a lot of garbage with our 24 acres.  We have a 3-yard dumpster which we've been filling pretty regularly.  When we had a visit from the local Les Schwab tire franchise to repair a flat tractor tire, we paid them a few hundred dollars to take away over a dozen used tires ranging in size from compact car to truck to tractor.  And then, there were the mountains of scrap metal.

Re-wiring and re-plumbing the house gave us a lot of copper--the old knob-and-tube wiring used 14 ga. copper, much heavier than the current standard, and there was a whole house's worth of the stuff.  There was also yards and yards of copper tubing from the old fuel oil system, a lot of copper sheet from I-don't-know-what, and lots of other copper junk.  Copper gets top dollar for metal recycling.

But, as Stalin remarked, quantity has a quality all its own.  Scrap iron--even "dirty iron" or "scrap/tin," the difficult mix of iron and copper and plastic and rubber and fiberglass represented by a used water heater or a bale of rusty fence wire--will only get you $130 a ton at the recycling places in town.  However, in cleaning up our fields and barns and fences and grounds, we accumulated two giant piles.  According to the receipts from the scrap yards, over the last week we have hauled away nearly five tons of

tin roofing
washing machines
water heaters
bits of a Model T truck
barbed wire
no-climb fencing
bent T-posts
oil drums
rusted-out troughs
dairy stanchions
tire chains
animal traps
water tanks
bridge supports
rusted-out culverts
mangled gates
bed frames
lumber dryer pipe

I still have to cut up the frame of the Model T truck so it will fit in the trailer (that's what the quail in the photo is perching on), but we have taken care of most of it.  The enormous piles of scrap--we've been accumulating them for so long that I've been using them as landmarks--are gone.  There is still about a ton of scrap in the creek below our house, but that will have to wait until next dry season; it is out of sight and for now out of mind.  Right now, I will enjoy the clearer view, and the fact that our property weighs a bit less.


This iron-rich scenario is true for many farms--it seems you can't pass a farm without seeing a dead combine or tractor or other rusting hulk.  And of course, being a microbiologist concerned with element cycles and a tree-hugger, it leads me to wonder.  Going in to the last century, most of the world's economically viable iron was still in the ground, concentrated in well defined deposits.  One of the unintentional goals of the last century was to take that concentrated, easily accessible iron and disperse it evenly across the face of the earth.  Getting iron out of the ground is unlikely to get any cheaper.  As it is, the economics of iron are such that people will pay me over a hundred dollars a ton for grotty iron.  They will then spend more money to separate it, put it on a boat, ship it across the Pacific to China, melt, and re-form it into agricultural implements or whatever.  Scrap iron prices fluctuate, but the trend is that they go up.

So, I wonder what it will be like five hundred years from now.  I assume iron will still be useful and valuable.  Where will it come from?  Will the iron cycle have closed on itself, as far as humans are concerned?  Will we still get iron from the ground?  Would the discovery of 4,000 kilos of iron in various oxidation states near a creek in Oregon be an economically significant event, or would it not even be worth fifty quatloos?  I just don't know enough about the geology on this, but it's something I wonder about when I see a fifty year old tractor rusting away in the corner of a field. 

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