Mining- Environmental Degradation & Sustainability Blog

The mine Mount Polley is located in Britsh Columbia, Canada. It's an open pit mine. Open-pit mining is removing minerals such as gravel, sand, and metal ores by digging them out of the earths surface and leaving an open pit behind. Minerals that are found in this mine are copper and gold. The Mount Polley property covers 18,794 hectares, which consists of seven mining leases totaling 2,007 hectares and 43 mineral claims encompassing 16,787 hectares. Copper and gold are a big thing in our society. Copper is in almost everything these days and we need them to live. 

Hazeltine Creek following the spill  (photo by Chris Blake).

 On August 5, approximately 10 billion litres of wastewater and 5 billion litres of solid tailings waste escaped the impoundment at imperial metals ’ Mount Polley mine in the interior of British Columbia. The creek that received the brunt of the flow was completely obliterated, some of the waste backed up into Polley Lake and some the wastes and debris from the torrent continued downstream into Quesnel Lake.Extraction  and processing methods, and how it can cause environmental degratation and pollution, and environmental impact 

• The grinding circuit consists of two parallel rod mill/ball mill circuits and a pebble mill circuit. Crusher product is first split between to two rod mills where it has water added to form slurries. The slurries are pumped to cyclones that classify the ore particles by size. The larger particles flow to feed the ball mills while the fine particles are discharged to the second stage of grinding: the pebble mill circuit. The ball mills are in "closed circuit", meaning that the discharge is pumped to the classifying units (cyclones) and the particles will not pass to the next grinding stage until they are fine enough to be classified as such. The second stage grinding circuit (the pebble mill circuit) also consists of mills, pumps and cyclones. Three pebble mills receive the coarse product from the cyclones, fed by pumps. The pebble mills are so named as they use pebbles (rocks obtained from the crusher) for grinding. Particles finer than 200 microns are then pumped as slurry to the flotation circuits 

• The flotation circuit separates the valuable minerals from the waste minerals. The particle size reduction described above is imperative to separation as the mineral grains are very fine, with a mean diameter size of 50 microns. The valuable minerals, mostly in the form of sulphides, are separated from waste minerals (gangue minerals) by floating and being collected and upgraded or cleaned

  "“Under the Boundary Waters Treaty, the U.S. and Canada are both committed to not polluting waters on their own side of the border to the injury of health or property on the other side of the border. Canada is not taking their treaty obligation seriously. We ask the State Department to work with Canada to ensure the treaty is respected and our interests are protected,” said Heather Hardcastle, a gillnetter and co-owner of Taku River Reds based in Juneau." Canada didn't really do what they had to do in their part. A mine that they compare the Mount Polley mine to is the Red Chis. Multiple large-scale, open-pit mines like Red Chris are currently in various stages of development in the watersheds of three productive transboundary salmon rivers, the Taku, Stikine and Unuk, which flow from B.C. into Alaska. "These projects raise red flags for many, including tribes, commercial and sport fishermen, tourism operators, municipalities and political leaders who have spoken out in numerous resolutions and letters." 

  
  
  
  
  Before picture.

         2014 picture 

  Before and 2014 picture from  http://en.m.wikipedia.org/wiki/Mount_Polley_mine_disaster  

• Sources: 

  
  

  http://www.imperialmetals.com/s/MountPolleyMine.asp

  http://www.sitnews.us/0215News/021015/021015_mount_polly_review.html