HardAssetsInvestor

Written by Tom Vulcan  |

October 25, 2010

Mercury: Finding Opportunity In The Toxic Trio

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In our latest installment of our Strategic Metals series, we investigate mercury, the final member of the Toxic Trio. How can investors play this controversial metal?

 

Remember our toxic trio: arsenic, the old poudre de succession; cadmium, the stuff of paints and batteries; and mercury, named for the ancient Roman god of speed, trade—and, these days, less and less.

Despite its extreme toxicity, mercury was once commonplace. It was often used in the milliner's trade—as mercuric nitrate, or Hg(NO₃)₂—to make felt for hats, with some quite unpleasant side effects: For one, those poisoned by the metal appeared insane, giving rise to the phrase "mad as a hatter." (The U.S. government finally banned this use in December 1941.)

And of course we all know of mercury's application in analog thermometers, although they're used increasingly infrequently in our daily lives.

In addition to causing horrendous birth defects, though, mercury can be quite fearsomely poisonous if it is handled or disposed of improperly. The disaster in Minamata, Japan in the 1950s, in which methylmercury-contaminated industrial wastewater poisoned the local populace, is just one case in point.

 

The Truth Behind The Metal

Like caesium, gallium and rubidium, mercury appears as a liquid at room temperature, and has many exceptional properties, including:

 

• Electrical Conductivity: becomes superconductive when super-cooled
• Expansion & Contraction: rate of either very consistent
• Reflectivity: excellent reflectivity
• Mobility: highly mobile—hence the appellation "quicksilver," where "quick" means alive
• Specific Gravity: 13.5 times that of water, which, together with cadmium, lead and zinc, makes it one of the "heavy metals"
• Stability: reacts neither in water nor air, in neither acids nor alkalis
• Surface Tension: six times that of water, mercury does not make wet surfaces with which it is in contact.
• Volatility: highest volatility of any metal

 

Whence Mercury?

The primary ore source from which mercury is mined, cinnabar, is a soft and dark red sulfide mineral—the darker the red, the better the grade. Mercury miners at the Santa Barbara Mine in Huancavelica, Peru (now closed) used to say "...sangre seca, ley mas alta." This translates as "if the ore is the color of dried blood, the grade is higher."

However, mercury can also be found, albeit rarely, as a native metal.

For cinnabar ores to be economically viable, they need to contain concentrations of mercury of at least 1 percent. According to the U.S. Geological Survey (USGS), most such ores generally contain mercury in concentrations anywhere from 0.1-2.0 percent.

Once mined, the metal is obtained by crushing, screening and then, without major beneficiation, retorting the ore. It can also be extracted by dissolution, electro-oxidation and leaching.

In certain regions of the world—Peru and the Western U.S., in particular—mercury is also produced as a byproduct from the processing of gold, lead-zinc and silver. The metal can also be found in coal, in minute amounts.

While historically such countries as Spain (Almadén), Italy (Monte Amiata), Peru (Huancavelica) and Slovenia (Idrija) have long dominated the production of mercury, now, as with so many other metals, the world's largest producer is China.

 

Source: USGS

*Estimated; Other Countries include: Finland, Mexico, Morocco, Russia, Tajikistan