Rare Earth Mining

WHAT ARE RARE EARTH ELEMENTS?

16 elements on the periodic table


From: http://pubs.usgs.gov/fs/2002/fs087-02/

  • Not actually rare
  • Used in magnets, batteries, electronics, magnets, lasers, hybrid cars, motors, LCD screens, oil refining, weapons of defence, etc.
  • Most uses are not ‘green’
  • Mining rare earths releases many air pollutants including: nitrogen dioxide, sulphur dioxide, carbon monoxide, particulate matter and dust fall.
  • Greenhouse gases such as carbon dioxide, methane and nitrous oxide are also released
  • Many companies market rare earth mining operations as ‘green’ as the intended use of some of the ores are in products designed to lower carbon emissions. Procedures used to obtain rare earths are very damaging to the environment and far from being ‘green’.
  • Historically rare earth supply worldwide as largely from China although in the past few years they have cut exports due to extreme damage to the environment and human health.

"According to the Chinese Society of Rare Earths every ton of rare earth elements produced generates 8.5 kg fluorine, 13 kg flue dust...9,600-12,000 cubic meters of gas (laden with flue dust concentrate, hydrofluoric acid, sulfur dioxide and sulfuric acid)...75 cubic meters of acidic waste water and one ton of radioactive waste residue" US EPA 2011

View Video Clip

 

While environmental legislation in China is not as stringent as in developed nations, rare earth mining has not yet been carried out anywhere in the world safely.  Proper handling and disposal of uranium and thorium continue to be a major challenge for the rare earth industry.

While Canada does have strict environmental laws in comparison to many other nations, Canada’s laws were not written with rare earth mining in mind.

The Metal Mining and Effluent Regulations (MMER) were not designed to manage or regulate all of the contaminants of concern in rare earth mining. The MMER does not consider thorium and uranium harmful substances and does not impose controls upon their release into the environment. Since their release during mining activities is not associated with the nuclear fuel cycle they are not regulated by the Canadian Nuclear Safety Commission (CNSC).

The MMER imposes maximum daily discharge limits on arsenic, copper, cyanide, lead, nickel, zinc, total suspended solids and radium-226. Other contaminants of concern are not regulated.

The processing of rare earth ores is frequently done on site and requires strong acids and bases (most often sulfuric acid, hydrochloric acid and lime). These chemicals must be transported to the mine site putting other areas at risk should spillage occur.
Wastes produced must be properly managed to prevent their entrance into the surrounding environment.

Rare earth mining has never been carried out in Canada, but there have been environmental disasters associated with rare earth mines in other developed nations.

Mountain Pass rare earth mine in California was shut down in 2002 in part due to environmental concerns. During its operation the mine released over 600,000 gallons of waste water containing thorium into the nearby desert ecosystem. Local groundwater has been contaminated with radium, thorium and strontium.

The Kerr-McGee company had 4 rare earth sites in the state of Illinois. These sites are now among the most contaminated sites in all of the United States.

 

EXPLORATION

  • Exploration can include surveys, field studies, drill test bore holes, air-borne magnetic, radiometric and gravity surveys
  • The exploration phase may also involve clearing of large areas of vegetation, usually in lines to allow entry of drilling rigs


Aerial view of Matamec’s exploration and site for the proposed Kipawa Rare Earths project.
Exploration carried out to date includes 293 drill holes and 13 trenches.

  • Many countries require an environmental impact assessment (EIA) to be done prior to the start of exploration. In Canada exploration can be carried out without an EIA and even without a prospector’s license. However , a prospector’s license is required to develop a property into a mine.

DEVELOPMENT

  • This phase involves the construction of access roads, which can have substantial environmental impacts.
  • Site preparation and clearing may involve the clear-cutting and/or burning of vegetation.
  • Dump trucks, bull-dozers and other heavy machinery are often used to removed soil and expose bedrock.
  • Open pit mining involves the use of explosives to remove ore. This blasting creates a great deal of dust causing negative effects on air quality. Blasting can also be harmful to fish, aquatic organisms and other wildlife.
  • Ores are extracted from deep underground. The resulting pit is often below the water table and will continuously fill with water (both from groundwater and precipitation). After mining operations cease a pit lake usually forms.

WASTE ROCK

  • Large quantities of waste rock are produced. The waste rock usually contains high levels of toxic and radioactive substances. The rock is normally left on site in large piles.

ORE EXTRACTION

  • Using heavy machinery the ore is extracted and transported to processing facilities. This process releases harmful dust and impacts air quality.

ORE PROCESSING

  • Ores extracted must be processed to refine and obtain the element or metal of interest.
  • Methods used to process the ore may include physical and chemical processes such as magnetic separation or chemical separation (leaching). Both methods are used in the processing of rare earth ores. Chemical separation requires the use of large quantities of strong acids and bases (usually sulphuric acid, hydrochloric acid and lime).
  • The processing generates large quantities of toxic and often radioactive wastes called ‘tailings’
  • Tailings are often stored on-site in tailing ponds for eternity.
  • While measures can be taken to prevent their release into the environment, such as the use of a geomembrane and tailings dams, these structures often have lifespans that are a great deal shorter than that of the toxic and radioactive substances that they
    are meant to contain.


The figure above shows the number of tailings dams failures over time - View PDF

The performance of a geomembrane is dependent upon many factors including temperature, exposure to UV-light, exposure to radioactive substances, as well as the materials used to fabricate the membrane and its thickness.

HDPE and LLDPE geomembranes with 1.5mm to 2.0 mm thicknesses are commonly used for tailings ponds. These geomembranes can have average lifespans as low as 36 years while the radioactivity of the materials they contain will persist for thousands of years. They may be sufficient to protect the current generation but not future generations.

Geomembranes can be damaged or punctured due to high loads, seismic activity, deformation of pipes connected to the drainage system. Geoelectric leak technology can be used to detect leaks in geomembranes but the mining industry has been resistant to its use despite the fact that it is economically feasible and helps reduce environmental risks.

Contrary to what many believe geomembranes are not completely impermeable. They do have leakage rates which are dependent upon many factors as described in the table below.

Once a mining company has closed its operations it is often up to the taxpayers of the region to manage the waste. This can be quite costly should an accident occur. In Kootenay B.C. the dam on a decommissioned tailings pond containing heavy metals began to give way, repairs cost over $500,000.
http://www.cbc.ca/news/canada/british-columbia/story/2012/08/03/bc-tailings-pond-kootenay.html

Please note: Information above is general information about mining and is not specific to any proposed project in the Kipawa watershed. All information provided is factual from written resources provided below. The Kipawa Lake Preservation Society and its members cannot be held liable for the information provided within.

Environmental, Economic, Socio-cultural effects of mining can be found here

To learn more about the mining process, tailings ponds, dams and geomembranes the following are useful resources

Open Pit Mining
http://biotools.earthmind.net/files/Full-Guidebook.pdf

http://www.abs.gov.au/ausstats/abs@.nsf/90a12181d877a6a6ca2568b5007b861c/ce28d7fbe5faa308ca256cae0015da32!OpenDocument

Canadian Mining Regulations
https://www.nrcan.gc.ca/mining-materials/policy/legislation-regulations/8726

Fugitive Dust (Air pollution)
http://www.arb.ca.gov/pm/fugitivedust_large.pdf

Tailings Dam Failures
http://www.infomine.com/library/publications/docs/Azam2010.pdf

Geomembrane Lifetime Predictions
http://www.geosynthetic-institute.org/papers/paper6.pdf

Geomembrane leakage rates
http://www.ausenco.com/uploads/papers/64034_Geomembranes_for_Tailings_Impoundments.pdf

Geomembranes and the mining industry
http://www.ausenco.com/uploads/papers/64061_Overview_of_Geomembrane_History_in_the_Mining_Industry.pdf