US aluminum mining plants employ different methods, sludge flood like Hungary’s unlikelyBy Ramit Plushnick-masti, AP
Thursday, October 7, 2010
Sludge flood like Hungary’s unlikely in US
HOUSTON — Images like those from Hungary of homes surrounded by red mud and cars floating through toxic sludge from a nearby metals plant would be unlikely in the U.S., where only two states have similar facilities, according to industry officials and regulators.
Texas and Louisiana are the only states with alumina factories like the one that malfunctioned in Europe, and they store the waste from the mining in a “dry” form, so even if a levee broke, the sludge could not become a threatening river, officials said. The levees that surround the storage beds also are designed to withstand winds from the most powerful hurricanes, and are periodically checked by state and federal regulators, the officials said.
“I don’t see it happening here,” said Susan Clewis, regional director for the Texas Commission on Environmental Quality’s Corpus Christi office, which oversees the state’s two aluminum mining facilities. “Our facilities store a drier material.”
In Ajka, Hungary, a reservoir that stored the red waste burst open Monday, rapidly becoming a devastating torrent of toxic mud, entering people’s homes, carrying away cars and killing at least four people. The ecological catastrophe is threatening the Danube River — one of Europe’s main waterways.
The sludge is a byproduct of refining bauxite into alumina, the basic material for making aluminum. Alumina plants are scattered around the world, with the 12 largest concentrated in Australia, Brazil and China. The United States produces about 1 million tons of alumina annually, making it 35th in the world for production.
Stephen Gardner, a spokesman for the Washington-based Aluminum Association, said when people from the industry lobbying group first saw the images from Hungary “it didn’t immediately make sense to us” because in the United States the material is dried before being stored. To have enough material to break a dam and flood a town “is pretty astonishing,” he added.
The three U.S. facilities are not required to “dry stack” the waste. But Sandra Bailey, environmental manager at the Sherwin Alumina Co. in Gregory, Texas, said dry waste is easier to handle and is less toxic. Most of the waste in Sherwin’s facility is 80 percent solid and strong enough for heavy equipment to ride on, she said.
Sometimes, the waste — which should be like damp, but not muddy, ground — becomes so dry it turns into dust and flies into the air, said Rob Bear, director of environmental affairs at Pittsburgh-based Alcoa, which has an alumina refinery in Point Comfort, Texas. To prevent that from happening, inspectors go out daily to check the consistency of the waste and adjust or turn on water sprinklers if the material is too dry.
To help dry out the material, Sherwin — and other U.S. companies — extract the caustic soda used to isolate the aluminum in the ore, allowing them to recycle the expensive material, Bailey said. Once the soda is removed, the waste is less alkaline then the pH value of 13 measured in Hungary, Bailey added.
The pH scale measures how acid or alkaline a substance is, rating from 0 to 14, with 7 being neutral. A lower number is more acidic and a higher number is more alkaline.
The facilities in Texas and Louisiana are also in the hot Gulf Coast, so the material can dry within days, depending on the weather and conditions in the stack, Bailey said. Sherwin has four large surface impoundments; the largest active one now is about 831 acres and holds about 21 million cubic yards of waste. When a storage bed is full or no longer useable, it is covered — much like a landfill would be — and foliage is planted on top to restabilize the land and restore the pH balance, Bailey said.
The waste has “almost every element on the periodic table,” including iron, which is what makes it red, Bailey said. “You will have lead, mercury, zinc, iron — just every metal you can think about,” she said.
Bailey conceded there are no guarantees against leaks in the levees but said they are inspected daily by workers who look for potential trouble spots. State and federal regulators inspect the levees at least twice a year.
In Louisiana, the Noranda Aluminum Corp. runs an alumina refinery on the bank of the Mississippi River at Gramercy. The facility was inspected last week by the Louisiana Department of Environmental Quality and no problems were found, said Sam Phillips, the solid waste administrator at the agency.
“The good news is that I’m not aware of any red mud lake failure in the United States,” he said.
In Gramercy, the sludge is contained in four large ponds, or red mud lakes, covering about 920 acres.
Phillips said an accident like the one in Hungary would be highly unlikely at the Gramercy plant. He said the clay levees containing the lakes are built at a grade, stability and height designed to contain the sludge. The facility has been through two major hurricanes — Katrina in 2005 and Gustav in 2008 — and was able to handle the rain that fell, he added.
“The situation you saw there (in Hungary) would not happen here because of the levee design and the water removal,” Phillips said.
Another difference: Louisiana and Texas aren’t hilly.
“It’s so flat here that it would be that hard to get that kind of energy mass built up that you have in a mountain area,” Phillips said.
Burdeau reported from New Orleans.
Tags: Eastern Europe, Europe, Floods, Government Regulations, Houston, Hungary, Lakes, Louisiana, Materials, North America, Texas, United States