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Molybdenum, the unpronounceable metal, is a timely topic for this holiday eve. And not just for the yellow-green fire that molybdenum adds to fireworks.
We celebrate the start of cleanup work at the Chevron Questa Mine Superfund Site in Taos County.
The decades of old-style molybdenum mining and milling near Questa left environmental problems for others to deal with. The current owner of the operations is Chevron Mining. Most of the mess was made by Molycorp, Inc.
How does mining work? Surface rock is removed to get at the ore. The ore is mined and sent to the mill nearby that extracts molybdenum and leaves behind the tailings to dispose of.
Mining began at the site in 1920. Open pit mining along the Red River was done from 1965 to 1983 and left 328 million tons of cut-up rock in nine piles around the pit. The rock, with sunlight, air and water, generates acid that moves as it will. The mining now is underground.
Most molybdenum is used to improve the strength, toughness, and wear and corrosion resistance of steel, cast iron and superalloys. In short, a little molybdenum makes other metals stronger and last longer. Metals being stronger for longer equates to less metal and less scrap.
Cleanup will begin in four areas.
First, steps will be taken to reduce the sediments entering Eagle Rock Lake during storm events and to reduce the metal and sediment load already in the lake. The actions will preserve trout fishing in the lake.
Second, PCBs are hazardous wastes from old-style electrical equipment. PCB-contaminated soil near the mill will be removed until the remaining level is safe.
Third, pipes will be installed to stop unused irrigation water from filtering through old buried tailings piles. The new routing will reduce the levels of molybdenum that have built up in the ground water.
Why do the concentrations matter? The complex stomachs of ruminants, such as cattle and sheep, put them at special risk of molybdenosis from too much molybdenum. Cleanup decisions apply knowledge from many fields.
The fourth cleanup action is removing the major deposits of tailings left from the hundreds of breaks and leaks in the old tailings pipeline that ran beside the Red River. Most of the spills occurred before a rubber-lined pipe was installed in 1991.
Progress is a rambling quest. Behold the marks of independent thinking.
Republican Gov. Gary Johnson pressed the EPA to put the Questa site on the superfund list. Such initiative is not the tribal custom in his party.
He had a feel for the mining environment from his biking on the mountain road along the Red River. It made a difference.
Engineers are a peculiar tribe. When Molycorp’s pipeline breaks were frequent news, I happened to meet an idea man in the coal mining business, who offered his engineer’s view of the old-style tailings pipeline.
At the water cooler after visiting his surface mine, he was proud to tell me, “I know why that pipeline breaks. The slope of it running beside the river is steeper than it should be.”
Sure enough. A quick look at a civil engineering handbook confirmed the design flaw. The old handbook told ways to fix the problem.
Some tribesmen ask, why should a company who did not do the damage have to clean it up? Without this rule, fouled sites would be easily sold so no one cleans up.
But look more closely at market pricing. We can be sure the known environmental problems at Questa lowered the price Chevron Mining paid to buy the mine and mill operations. It only makes sense.
A smart company can make smart business deals using its knowledge and skill in environmental cleanup.
Celebrate the Fourth of July and all that it symbolizes. Appreciate the political, technical and economic ingenuity to improve what has gone awry.
Los Alamos Columnist