This next series of topics will be focussing on the faunal, floral, geomorphological and societal consequences of mining, followed by a guide to the ideal environmental practices that should be initiated once mining operations have ceased in the area. It’s important to discuss the ramifications that mining has on an area, due to the close relationship between mining and the health of the Australian economy. It’s not desirable that as this country’s economic dependency on mining shifts to renewable energies that mining be tossed aside. Mining is a fundamental part of Australia’s exports. Hence, why it is critical that mining adapts to these changing times. 

As we as a society become more aware of the environmental consequences of our actions, we are more likely to favour practices, and invest in projects, ideas and actions that protect environmental interests, whilst also progressing in our countries prosperity and development. At the 2019 Informa conference in Sydney, there were multiple mentions from financial consultancy agencies that activities, projects and plans including that had high carbon emissions, and/or direct/indirect environmental damage, have been classed as a risky investment to banking institutions. With some banks now introducing a section of paperwork specifically asking for the total carbon footprint of a project. Banks have shifted their views as to what practices are deemed risky or safe to invest in based on these carbon footprint projections, this is also based on the societies and markets adaptation of “green technology”. This is likely resulted from the exponential increase in renewable energy investment, not only in Australia but worldwide in the last decade. 

 There have been rebuttals to this statement, as to where do we draw the line between adapting to protect the environment, but also standing in the way of progress. The ideology of “progress” and the mining and construction industries are closely linked. As when we picture a developed nation, we base this premise on the state of the construction of a countries buildings, and the development of its markets. These two industries in  Australia have a unique opportunity to grow exponentially, if given the right circumstances to adapt to new technologies, and improve practices that minimise environmental impact, but also continue to provide the Australian economy the resources it needs to continue to propagate. This is the reason why the Australian mining sector has the opportunity to redefine itself to adapt and become environmentally friendly, rather than at the moment, being portrayed as the enemy of the environment. 

The upcoming articles will focus on operations and mining practices that in the last 100 years have proved to be environmentally unsustainable and damaging. The long term consequences of these poor mining practices will also be expressed, and evaluated from relevant case studies. These cases will be compared to other cases where appropriate steps were taken to fully rehabilitate an area. Finally, when it comes to post-mining operation rehabilitation, there will be a concentration on the considerations that must be made when restoring the integrity of the environment in the area of the mine site. But first we must establish the extent to which the environment has been affected by mining processes. 

 

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Surface Mining

Mountaintop Mining

Mountaintop mining processes create a large accumulation of toxic substance such as sulphates, calcium, magnesium and selenium. Due to the high elevation, and topography of the land, as rain falls, the water transports these potent chemicals into local water sources and/or underground water aquifers. This is however dependent on the frequency of rain events, as well as rate and quantity of rainfall. The effect of these leachates triggers an increase in electrical conductivity in the water ( which is a method of measuring heavy metal concentrations in water sources). The contamination poisons all living organisms in the water ecosystem. There are have been numerous reports that sulphate concentrations have exceeded acceptable levels by 800x – 2000x. This has sparked serious concern for bio accumulation and biomagnification in these marine ecosystems. There have been studies that have confirmed that as a result of these high concentration in chemicals, there have been defects in organism larvae and organism physiology over its maturity and development. 

Mountaintop mining requires the deforestation of a large area to setup the mine, and access points. This significantly decreases the biodiversity of organisms within the area. Once an organisms habitat is cleared, the mortality of these organisms in the area sky rockets, including birds, mammals, fish, and insects.  

The most pressing issue from mountain mining is that even after the mine has been closed for 15 years in some cases, minimal changes have been observed in faunal regeneration, and population numbers of local fauna. Suggesting that the soil, land and conditions are not suitable for plant growth, and life propagation.

Strip Mining

Strip mining, is commonly known as the most destructive mining process, it operates by scraping away the surface layer of the earth collecting mineral ore. The surface level blasting operations, involved with strip mining, leaves long term scars on the landscape. This process requires less labour and yields usually more coal than underground mining, which is the motive as to why it’s frequency of utilization is high. However, the environmental and ecological consequences are extreme. Any flora, is ripped from its roots, destroying the habitat of all species in the area. The surface soil is completely disrupted and overturned, and left to the natural forces, which leads to heavy wind and water erosion. In heavy rain events, the loose soil can be transported into nearby streams and river systems, which can increase the turbidity (clarity of water) of the river systems. The consequence of increased turbidity leads to death for many river organisms from disorientation and suffocation.

If there are any chemicals or leachates in the top soil, such as fertiliser, pesticides or sulphates, when transported to the river system, these chemicals can cause contamination of the estuarine or marine system. Some toxic chemicals in particular, can cause bioaccumulation and biomagnification in the fauna. This is the concept of an organism absorbing a toxic compound into their body and storing it in the fatty tissue (bioaccumulation). Biomagnification, is the process of the chemical being magnified, when a larger organism ingests the contaminated smaller organism. As the larger organisms body absorbs the nutrients from the smaller organism, it also absorbs the toxic chemical that it cannot process, and is hence stored in its own fatty tissue. When repeated multiple times, the magnification of the toxin becomes more and more concentrated, slowly killing the organism.

If there are any contaminants left by the mining operation, the chemicals can easily be transported into the soil, or the water-table causing contamination of underground water reservoirs through consistent rainfall. However, the environmental disruption does not stop there, with dust and noise pollution also driving away fauna, and disrupting the lives of residents that may reside close by.

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Open Pit Mining

Open Pit Mining has similar environmental consequences as strip mining and mountain mining, in terms of deforestation, biodiversity impacts, sinkholes, contamination of surface and groundwater systems. However, two consequences that are unique to open pit mining is artificial slope deformation and instability of rock formations. Due to the large scale of open pit mining operations, the integrity of rock formations can be compromised leading to collapses, landslides and mass flow. Especially after flashing flood or heavy rainfall events. As the rain is absorbed by the soil, the structure of the soil softens, causing large rock to collapse under its own weight. 

The effects of mining usually result from a range of consequences that affect each other. For example, vegetation acts as a soil stabiliser, meaning the moment that it is removed, the soil becomes “loose”. Not only is the slope artificially created, but the ground is without vegetation to anchor the soil. Furthermore, the damages inflicted onto the ground from structures, vehicles or processes such as blasting, naturally reduces the lands ability to retain water. If this consequence is coupled with consistent disturbances and as mentioned above, the removal of vegetation, landslides are eventually triggered. Over time, it is common to witness an onset of desertification as a result of the severity of land disturbance, even after the mine has been closed or abandoned. 

Underground Mining

Underground mining, is known as a less impactful type of mining, however, the environmental devastation is still noticeable. The process of underground mining includes the filtration of a large quantity of rocks and minerals under the surface of the earth. The consequence of filtering through large quantities of rock, is the shear quantity of waste earth that is generated. The waste rock is comprised of a range of chemicals and materials, that if exposed to air can chemically react and can become toxic. 

The toxic waste rock is stored as large stockpiles on the mine site. Again, the same environmental issues arise. The destructive forces of wind and water erosion slowly begins to take its effect on the stockpile, which can cause run off, leaching and contamination to nearby water sources and soil. More importantly, the toxic dust can damage the lungs of the workers in the area. 

Until recently, it was believed that water was a sufficient method of controlling toxic dust. Even though the mining is underground, the generation of dust is significant due to the limited ventilation, which hence requires a large quantity of water in the attempt to suppress dust suspension. The indirect consequence of this action is that when water comes into contact with coal and other minerals. The result is a toxic liquid waste contaminated with minerals and heavy metals. This toxic water leaches out of abandoned mines into ground water aquifers, soils and water systems. The process is also referred to as Acid Mine Drainage. All life that comes into contact with this toxic substance is poisoned, thus leaving a baron wasteland, where fauna cannot propagate due to the toxic soils, and animals cannot inhabit the environment due to the lack of habitat protection and contaminated water sources. 

As can be clearly seen by the processes above the extent at which the environment can be impacted. It affects every part of the environment, from air to water to earth, on a physical and chemical level, as well as micro and macro level. This is why it is fundamental that the appropriate provisions are put into place to ensure that adequate rehabilitation occurs.  The final article of this trilogy will also provide critical metrics that should be introduced to ensure that rehabilitation is successful weeks, months and even years later. There is only one Australian environment, and it is our duty of care to play our part in protecting it in the short and long term.

 

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