Oct 18, 2007

Lewis and Clark meet coal fly ash materials

Mandan, ND, was where Lewis and Clark spent their first winter, across the Missouri River from a town of native people. They visited back and forth, traded, and generally had as good a time as possible without cable TV, cellphones and WiFi. There were 45 guys – Sacagawea spent most of on the other side of the river – living in a space about the size of a large workcell.

Now there is a replica of the Fort Mandan with a grizzled historian who looks like Santa Claus in a checked shirt. What I really want to tell you about is the sustainable construction of the visitor center.

In fact, it is billed as “Headwaters Fort Mandan Visitor Center.” Headwaters Resources (NASDAQ:HDWR) says it is “America’s largest manager and marketer of coal combustion products, including fly ash, working with more than 110 power plants nationwide and marketing more than 6 million tons of coal ash annually.” It says it is “committed to sustainable business practices and sustainable products.” That can mean anything, of course, and I’m just looking at their brochure.

The visitor center is a showcase for the use of some of their products, but only incidentally. It does a pretty good job of illuminating the historical context of the fort and the Lewis and Clark expedition. It’s a nice looking building inside and out.

Coal fly ash is the material that goes up the chimney when coal is burned, that has to be captured somehow to keep it out of the air. So what do you do with it then? Headwaters uses it to replace up to 70% of the cement in the building’s concrete, saying it imparts more strength, durability and chemical resistance to the material. (How much of concrete’s volume is made up of the cement?)

The concrete that Headwaters used in Fort Mandan’s visitor center is called FlexCrete aerated concrete. It is one-fifth the weight of ordinary concrete. Air bubbles fill out the volume of the concrete and provide sound and thermal insulation. The brochure says coal fly ash comprises 70% of the volume of FlexCrete. I’m getting confused now about relative volumes of fly ash, other incredients of the cement, and the other ingredients of the concrete, but let’s just say that they’ve got a pretty interesting material that uses up an otherwise wasted combustion byproduct.

The ceiling tiles contain fly ash, as does the artificial stone that covers the exterior walls and the interior fireplace, and the stucco that covers the interior walls. Trails are constructed with a soil cement mixture containing 50% coal fly ash. They even got the carpet manufacturer to use the fly ash in the carpet backing. The concrete floors, sidewalks and parking lot surface are laid on a base layer of coal bottom ash. You might have guessed, but that’s the ash that doesn’t fly up the chimney and has to be shoveled out somehow.

I don’t know how many tons of coal byproducts were used at the visitor center to replace other materials, but ONE TON used conserves the equivalent of an average American’s solid waste landfill content for more than a year. It reduces CO2 emissions equal to two months of driving a car. And it saves enough electricity to power the average American home for 24 days. Considering that Headwaters claims to reuse 6 million tons of the material in a year, that’s better than doing nothing.

If you went deeply enough into the processes used throughout the coal mining, burning, waste disposal and reuse, you’d probably find that Headwaters is only providing a tiny bit of sustainability to the total system, but it’s better than nothing. And it’s a lesson that there are viable businesses to create out of unexpected resources.

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