Published with permission.
Dear Editor (re letter by Keith Dance)
Mercury was used in gold mining operations for the separation of fine gold particles through amalgamation then burning.
Elmer Diaz, University of Idaho, states “during the amalgamation process, a good amount of metallic mercury is also lost to rivers and soils through handling under rough field conditions. Mercury-rich tailings are left in most mining sites. It is expected that soils around mining sites should also be contaminated.”
Up to 87% of the mercury used vaporises and is dispersed into the atmosphere, being deposited onto forest soils and rivers, to be absorbed by vegetation.
New Scientist magazine 08/09/2001 reports that according to the National Centre for Atmospheric Research in Colorado,”about 95% of the mercury stored harmlessly in the forest is spewed back into the air when the trees are burned.
The University of British Columbia reports that ALL trees contain some mercury.
According to a Bega Metallogenic Map and Mine Data sheets, 1978, there were 318 registered mines from the Victorian border to Bingi. 227 of these were registered as mining gold. Contrary to what Keith implied, less than 20 of these mines were in an alluvial geological setting, the rest were mainly shaft mines, with a few open-cut and shallow pit operations.
Many of these 227 mines would have used mercury.
Some mercury is present in the trees that will be burned by the charcoal plant. All mercury in these trees will be vaporised then emitted into the atmosphere. There appears to be an oversight in the EIS because there is no mention of mercury emissions in the document.
The Charcoalition has called on the NSW Government to include this issue as part of the assessment process.
In particular,the mercury content of trees destined for the charcoal plant the amount of mercury vapour that would be emitted from the retorts, and the health impacts of such emissions.
Keith is right – mercury is crap, and we don’t want any more of it in our environment.