Mining officials say mercury not used today

Wednesday, Jan. 14, 2004 | 9:49 a.m.

Nevada mining and mineral officials say that while a Las Vegas teen obtained mercury from supplies a relative used in private gold mining and got seriously ill, their industry is not the culprit for excessive mercury in communities.

"No licensed mining operation in the state uses mercury in its operations," said Alan Coyner, administrator of the Division of Minerals in Carson City.

"The only people who use mercury are amateur prospectors who employ methods that are a throwback to the 1800s. They use it because mercury attracts gold and silver -- an amalgam that pulls it out -- so that gold can be more easily recovered during a heating process."

Russ Fields of the Nevada Mining Association, a trade association that represents 30 gold mining operations and other mining interests that together employ 10,000 people, echoed that sentiment.

"The last company to use mercury in a commercial gold mining operation stopped at the start of the 1900s," Fields said. "Developing countries still use the amalgamation process, but in the United States such operations are arcane."

According to the U.S. Geological Survey, the last United States mine to produce mercury as a primary commodity was the McDermitt Mine -- also called the Cordero Mine -- in Northern Nevada. It closed in 1992.

However, Coyner said, Nevada gold mining companies do recover minute amounts of mercury as a byproduct when processing gold and silver. No statistics are available on how much mercury is mined in Nevada or nationwide as byproducts of gold and silver, the U.S. Geological Survey says.

Nevada is one of the world's largest producers of gold with 8 million ounces mined per year. If Nevada were a country, it would be the world's third largest gold producer behind South Africa and Australia. Instead, Nevada makes the United States the world's second largest gold producer, Fields said.

Still, Fields said, the amount of mercury recovered from that much gold ore is "tiny" and that Nevada mine operators sell it only to "legitimate companies that have a legitimate use for using mercury."

The largest domestic end use for mercury in the United States today is the chlorine-caustic soda industry, the U.S. Geological Survey says.

Chlorine is an important industrial chemical that is used in the pulp and paper industry, water treatment, defense against biological attacks, antibiotics, microprocessors, computer housings, flak jackets, helmets and bullet-proof glass, the survey says.

About 6 million mercury thermometers each containing 0.7 of a gram of mercury were sold in the United States in 2000. Modern digital thermometers do not use mercury, Coyner said.

Mercury also is used in car switches and lamps -- it's an environmental concern during the scrapping of wrecked vehicles -- as well as in thermostats, dental amalgam and batteries. However, there are programs to recover mercury from all of those items, the survey says.

The Environmental Protection Agency in 1971 classified mercury as a hazardous air pollutant. The U.S. Geological Survey said that in 1998 an estimated 650 kilograms of mercury was released into the atmosphere during precious metal smelting in Nevada.

Fields said air quality levels at mines are constantly monitored for mercury vapors and that the amounts released into the atmosphere "have been coming down."

The U.S. Geological Survey says Nevada mine owners began in 2000 a plan to voluntarily reduce mercury emissions by 50 percent.

The survey says the greatest sources of mercury pollution include coal-fired power plants and industrial boilers, municipal and medical waste disposal, recycling and hazardous waste disposal, chlorine-caustic soda production and volcanic activity.

Nevada's mining industry was not listed as a major mercury polluter by the survey.

Mercury, which Coyner said is present in insignificant amounts of all soil and vapors around us, is available for sale in the United States.

"You can buy mercury from scientific supply companies for lab experiments at places such as major universities, and you can perhaps buy it over the Internet," Coyner said. "But you can't readily get it at hardware stores and other retail outlets these days."

Larry Tirri, director of environmental health and safety for the University of Nevada Las Vegas, said the university has in recent years "minimized the use of mercury" in experiments.

At this time he does not believe any mercury is being stored on campus and, if there is any, he said it is small in quantity and secured.

"If we have any mercury it would be used in research at the faculty and graduate research levels," he said. "We've even phased out the use of mercury thermometers."

Tirri said the only mercury in a home should be in a thermostat, light switch and, if necessary, a thermometer.

"If it is in our homes (unsealed and in liquid metal form) we need to get rid of it responsibly," he said.

The use of mercury more than 120 yeas ago caused the need for a federal Superfund cleanup study for one Northern Nevada river.

"Mills along the Carson River during the Comstock days, 1860-80, used large quantities of mercury, and in recent years that became the subject of an EPA study," Coyner said.

The results of that study were to continue to monitor mercury levels in the river from Carson City to Lake Lahotan, but not to clean up methylmercury because disturbing the elemental or natural mercury on the bottom could cause an even bigger environmental problem, Coyner said.

Still signs are posted along parts of the river prohibiting fishing because of food chain mercury contamination.

Also, Coyner said, because of construction and mining that disturbed mercury, arsenic, lead and other such elements in the soil, Nevada about four years ago was ranked No. 1 in the nation by the EPA for toxic release inventory.

However, the EPA has since redefined its toxic release inventory standards to exclude soil disrupted by construction and Nevada no longer is a national leader in that pollutant, Coyner said.