Mining- Environmental Degradation & Sustainability: Newmont's Mining Operations

 

                Newmont is one of the world's largest producers of gold and holds

 numerous active mines in a wide range of locations, including Nevada, USA. Numerous environmental problems are associated with these hazardous open pit mines. Most of these issues regard water quality, water usage, and mercury air pollution. Without proper care, Newmont's mining operations will become immensely harmful to the environment.

               The Newmont open pit mines are used to extract gold which can be found in both high-grade and low-grade ores using different extraction methods. Gold is a highly valuable mineral that is used to make a wide range of products that are used today. Some items that contain gold are currency, jewelry, electronic devices, and furniture. Its rarity, usefulness and desirability make it command a high price.

                     

 

 

          There are several methods to extract and process gold depending on the ore. The most common method is dewatering. During this process, water is pumped out of the ground surrounding the facility to have easier access to the gold ores within the "Cone of Depression." High-grade ore is mined by excavating large amounts of earth to get a small sum of gold. For every ounce of gold refined, approximately 100 to 200 tons of earth had to be moved (Environmental Problems at Newmont Mines in Nevada 11 Jan. 2011). Gold is extracted from low-grade ore using the cyanide heap leach method, in which the crushed ore is formed into a heap and sprayed with a solution of odium cyanide. The cyanide solution filters through the ore and dissolves the tiny particles of gold. Afterwards, the solution of gold is caught at the bottom of the pile and then pumped to processing facilities.

         All of these methods result in some form of environmental degradation and pollution. After the gold mines extract gold, the waste is discharged into "holding ponds," called tailings impoundments which can affect the water quality as well as all living organisms located there. In the process of dewatering, a huge amount of water is needed. Water is a critical resource in the dry Great Basin and the large scale dewatering activities at the mines impacts regional water resources upon which all life depends on (Environmental Problems at Newmont Mines in Nevada 11 Jan. 2011).
It can take hundreds of years to reach a new equilibrium water table, and the new level is likely to be lower than the pre-mining level, due to the existence of a "pit lake."(Environmental Problems at Newmont Mines in Nevada 11 Jan. 2011) Pit lakes can also become toxic when the walls and bottom react with the air and groundwater. Besides being a hazard unto themselves, toxic water from the pit lake can infiltrate back into the surrounding groundwater system therefore polluting it.

 

Cone of Depression

 

                                                          

                Water flows down to lower points, and the cone of depression could change the direction groundwater flows in and eventually result in ground water contamination.  The cone of depression might also affect whether the pollution flows toward or away from the well. Changing the direction the groundwater moves isn’t the only effect pumping may have on groundwater. If water is pumped out faster than it can be replaced, the water table will drop and the well might run dry temporarily and water supply will decrease in the entire region (a "drawdown").

               As of 2007 the Gold Quarry/Leeville/Carlin operations were pumping about 50,000 acre-feet of water per year (equivalent to the annual water use of 93,000 people in an urban setting.) In addition to water contamination, these gold extraction methods also result in acid mine drainage. Acid mine drainage is the process of rock "rusting" due to the exposure to air and water. The acidified water corrodes the rock to dissolve out various minerals that become hazardous to the environment and highly unhealthy for wildlife and humans. (Environmental Problems at Newmont Mines in Nevada 11 Jan. 2011).

 

 

 



Acid Mine Drainage

                   Like the tailings impoundment, the heap leach pile needs secure containment to prevent contamination of the ground and water table. Newmont pollutes groundwater and surface water with mercury and other toxic chemicals, resulting in the little water in the area to be polluted.
 Gold ores commonly contain various metals, but mostly mercury. Pure mercury is a liquid at room temperature, and is gasified easily during mining processes, sometimes reacting with other substances. Mercury is released into the air from gold mines as either mercury vapor, ionic or charged mercury, or bounded to adsorbed mercury. Mercury is known as the most dangerous heavy metal because it is extremely toxic to humans and moves freely throughout the environment. It is connected to various nervous system disorders such as intention tremor, poor mental concentration, and emotional ability. Mercury can also affect the kidneys and immune system. One of the common end products of mercury in the environment is methyl mercury, an insidious form that concentrates in the food chain (Environmental Problems at Newmont Mines in Nevada 11 Jan. 2011).

 



Cyanide Heap Leach Method

                 Minimal substantive action has been taken to resolve this environmental degradation due to its complexity, but there is no doubt that effort has been put in. An example of these efforts is that The Great Basin Research Watch has been trying to work with Newmont and state and federal regulators to handle and prevent damage done. Another example is the time the Environmental Protection Agency gave Newmont, mainly its Gold Quarry Mine, a notice of violation for four issues: failure to identify toxic materials in the mining waste, failure to meet waste treatment standards, generation and storing of waste without a permit, and failure to minimize the release of hazardous waste into the environment. The Resource Conservation and Recovery Act is a federal law meant to control the disposal of hazardous waste.(Environmental Problems at Newmont Mines in Nevada 11 Jan. 2011).  Actions have been taken for restoration and reclamation relating to issues such as acid mine drainage and pit lakes. An investigation ensued determining specific leakage points in the tailings dam and identified a contamination plume(Environmental Problems at Newmont Mines in Nevada 11 Jan. 2011). A trench drain system was devised to effective catch any contamination, and a series of monitoring wells was put in place to assure that the contamination plume was not advancing(Environmental Problems at Newmont Mines in Nevada 11 Jan. 2011). It is unclear at this time whether the trench system is capturing all the contamination from the tailings, and further analysis is most likely needed to assure that springs and groundwater is not being impacted(Environmental Problems at Newmont Mines in Nevada 11 Jan. 2011). Newmont needs to determine the source of the water, and see if it can be redirected. If not, active management will be required for an extensive amount of time.If Newmont had a better understanding of the hydrodynamics, this problem could have been avoided. To resolve all of these environmental problems, Newmont would have had to consider environmental protection to be at least as important as the profits from the gold extracted.

                                                                 Works Cited

"Environmental Problems at Newmont Mines in Nevada" Great Basin Resource Watch 11 jan. 2011. Web. 10 mar. 2015.

Gold Coins-http://learngoldcoins.com/wp-content/uploads/2011/06/gold-coins-and-banks.png

Acid Mine Drainage-http://yre-connect.com/wp-content/uploads/2013/04/Photo_33.jpg

Gold Heap Leaching-http://www.artinaid.com/2013/04/gold-heap-leaching/

Cone of Depression-http://www.sustainableaggregates.com/sourcesofaggregates/landbased/water/water_opsstage_page2.htm