Rio TInto/Kennecott Mining Company has been drilling core samples near Tamarack since 2000 to assess the likelihood of copper/nickel mining in the Big Sandy Watershed. Concerns include:
* Mining and processing copper/nickel ores releases sulfides into
the environment, forming sulfuric acid which extracts toxic metals
such as arsenic and mercury
* Sulfuric acid can be converted to sulfide by bacteria and dissolved
organic carbon in the sediments of lakes, rivers and streams
* Sulfide reduces the germination of wild rice seeds resulting in a
decrease or elimination of wild rice
* Mercury in water can be converted to methyl mercury, a known
toxin that bio-accumulates in fish and that when consumed can
cause brain damage and reduced intelligence
* The reaction of sulfides with iron phosphate in lake sediments
may release soluble phosphate, a nutrient that causes excess
algae and weed growth in lakes, streams and rivers.
Because a key objective of BSLA is “To advocate practices that protect and improve water quality,” BSLA’s position on potential mining in the watershed is to support a stringent sulfate standard for water discharges with financial assurances. Metal mining has a history of causing pollution for many decades following closure. Financial assurances are needed to treat water discharges and leachates following closure.
For additional information on mining in Minnesota and related news articles see MiningTruth.org.
For information on Rio Tinto/ Kennecott activities in the Tamarack area see
For information about the effects of sulfide on wild rice production see