Environmental effects of acid mine drainage
Acid mine drainage is a chemical reaction that occurs when water passes through a mineral rock containing sulfide. It occurs naturally – particularly in locations such as mines and construction sites where there are plenty of these exposed rocks containing sulfide.
Acid mine drainage can sometimes be referred to as rock mine drainage. Put simply, it is the outflow of contaminated water from metal and coal mines. This water becomes contaminated when rain or a stream comes into contact with a mineral that is rich in sulfur.
Contaminated water is one of the many challenges faced by mining industries all over the world, as it affects the country’s water infrastructure. The acidity levels in the water make it unconsumable and harmful, thus, having an effective acid mine drainage water treatment plant is key in reducing the impact of mining in the environment.
You might be wondering how mines generate acid mine drainage. Well, it forms when pyrite is exposed and it reacts with water and oxygen. It then forms sulfuric acid. Traces of the acid mine drainage can be found in streams and will have a yellow or orange colour.
Environmental effects
There is a range of environmental effects caused by acid mine water, and the most obvious one is how it’s affecting the water supply of its surrounding areas. For years, the mining industry has contributed to the country’s wealth through its natural resources. But, on the other hand, it has singularly posed a direct threat to the future of life on earth.
The manifestation of acid mine water, which is primarily found underground, rises to the surface and becomes harmful to the residents who live near these mines. The risen water makes contact with sulphide which then increases the acidity in the water.
The environmental effects are not only restricted to the water supply. It also affects the livestock, soil and wind by causing a blanket effect on surrounding residential areas. Additionally, when acid mine drainage travels and contaminates its surroundings, it affects the soil which means that it directly impacts the crops and plants that grow in the area.
Economical effects
It is no secret that the mining industry contributes significantly to our country’s economy by means of mineral trading. Another industry that suffers due to acidic drainage is the fishing industry. The fishing industry will decline because the acidic drainage travels through streams and into rivers and the sea, thus affecting the environment in which fish live in.
When a region is impacted with acid mine drainage, not only does the economy lose money but more money is lost when redressing the problem by cleanups and biological mine water treatments.
How to deal with acid mine drainage
A clean-up is one of the most common acid mine wastewater treatment methods that are used. But bear in mind that it isn’t the only one. Here are a few ways to deal with ADM:
- Solidifying the acid-producing mineral with concrete or cement.
- Surface water diversion: redirecting the water from the mines and preventing it from flowing through the acidic drainage, carrying minerals.
- Depositing the waste from the mine underwater to avoid being exposed to oxygen.
- Dry covers: this prevents the penetration of water and oxygen. Without these two components, the microbial oxidation of sulfide minerals decreases.
The mining industry is well aware of the negative impacts of acidic drainage. And in the efforts to treat the acidic drainage, the industry uses chemicals as an active treatment to treat the contaminated waters. Acidic drainage has the capacity to occur decades after a mine has been shut down, and will continue to manifest if it is continued to be left untreated.
Final thoughts
Once the water becomes contaminated, there are certain corrective measures that can be put in place to better manage it. But these measures come at an expense.
As the water becomes more acidic, it can dissolve other metals such as lead, copper and mercury which leads to further contamination in the water. One major health risk associated with a miner who works at a mine or a person who is in close proximity to the contaminated area is black lung disease. This is caused by breathing in coal dust, hardening the lungs.
Other health concerns can be chronic obstructive pulmonary disease, hypertension, kidney shutdown and cardiopulmonary disease. If your business or house is in close proximity to a mine, make sure that you take these diseases into consideration.