I drive the Marquam Bridge daily, and on the east end by Southeast Water Avenue is a pile of rock and broken cement that neither grows nor gets smaller, even though giant backhoes are active there daily. What's going on?

—Steve B.

Upon receiving your letter, Steve, I immediately began dusting off my time-worn lecture about how Portlanders can't stay abreast of the civic improvements undertaken in their names.

I was confident the answer to your question would involve the MAX Orange Line, or the Southeast Water Avenue Relocation Project, or some other public-works initiative I would pretend I'd heard of once I'd looked it up.

Imagine my surprise, then, when I discovered that your big pile of rocks is, more or less, a big-pile-of-rocks store.

Yes, what your bleary eyes have beheld each day is the Portland yard of the Iron Horse Group, your one-stop headquarters for recycled stone, gravel and riprap, and purveyors of fine rubble to the crowned heads of Europe.

OK, maybe not. Still, the reason the pile never changes size (it just sits there looking pretty much exactly like the place where Fred Flintstone used to work) is because it's the inventory.

Concrete and asphalt recycling is a real business, and—despite its post-apocalyptic appearance—a linchpin of green construction practices.

In olden times, you'd tear down a concrete building and haul away the rubble in exhaust-belching trucks. Then you'd haul gravel in more trucks for a new concrete building on the same spot. Meanwhile, the old rubble went to the landfill, where it probably crushed a family of spotted owls.

It only took society 200 or so years to realize that this rubble can be turned into gravel on site. Or, failing that, crushed to fist-sized chunks suitable for stoning infidels who won't stop saying "Jehovah."

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