Effects of Gold Mines On Water Tables: Abridged Version #goldmines #environment #novascotia

Summary

The speaker, a geochemist with a PhD from Princeton and experience in environmental groups, discusses the severe environmental impact of hardrock mining, particularly acid mine drainage. They highlight the perpetual issue of contamination from naturally occurring elements like arsenic and mercury, exacerbated by modern open-pit mining practices. The study comparing predicted and actual environmental impacts from mining reveals a concerning underestimation of water quality degradation, with 75% of mines exceeding aquatic life and drinking water standards.

Takeaways

• 🧑‍🔬 The speaker is an independent consultant with a PhD in geochemistry and over 25 years of experience, working with government agencies, environmental groups, and nonprofits like eTech International.
• ⛏️ Acid mine drainage is the most significant environmental issue related to metal mining, and it’s a persistent problem, often resulting from large-scale open-pit mining.
• 🌍 Open-pit mining is increasingly common because it's cheaper for companies, but it's more disruptive to the landscape and results in long-lasting contamination risks.
• ⚠️ Mercury and arsenic are the primary contaminants of concern in mining, particularly in areas like Nova Scotia where naturally occurring arsenic is already present.
• 🐟 Even without mining influence, arsenic levels can pose a threat to aquatic life, but mining drastically increases the concentration of these contaminants, impacting water quality and local ecosystems.
• 💡 Antimony, a toxic metal similar to arsenic, is also found in these mining areas and poses a serious health risk to both humans and aquatic life.
• 🔄 Mercury and arsenic naturally occur in the rock, but mining activities that expose and crush the rock release these toxins into the environment, leading to bioaccumulation in aquatic food chains.
• 🌊 Water systems in regions with mining activity are vulnerable to contamination, threatening drinking water sources and fisheries, including salmon habitats.
• 🛠️ Mines that produce acid drainage require perpetual care, maintenance, and treatment. Some mines, even from Roman times, continue to produce acid, showing the long-term environmental impact.
• 📊 A study on 471 large mines in the U.S. showed that 75% of environmental impact statements underestimated water quality impacts, leading to significant unanticipated contamination.

Q & A

What is the background of the speaker?

The speaker is an independent consultant based in Boulder, Colorado. They have a PhD in geochemistry from Princeton University and have over 25 years of experience working as a geochemist, researcher, and consultant for state and federal agencies, environmental groups, and as the chief scientist for eTech International, a nonprofit working mostly in Latin America.

What is the primary environmental issue associated with hardrock mining?

The primary environmental issue associated with hardrock mining is acid mine drainage, which is the number one environmental water quality problem. It occurs when exposed minerals in mined areas react with air and water, creating acidic runoff that can contaminate surrounding water bodies.

What is acid mine drainage and why is it a significant problem?

Acid mine drainage is an auto-catalytic reaction that happens when sulfide minerals in waste rock or tailings are exposed to air and water, producing sulfuric acid. This acid can leach harmful metals from the rock, leading to severe water contamination. Once started, it's difficult to stop and can persist for hundreds or thousands of years.

What mining practices are contributing to increased environmental disruption?

Modern open pit mining, which involves digging large holes in the earth and extracting all materials, is more disruptive to the landscape compared to older underground mining methods. Waste rock and tailings from open pit mining are often left on the surface, where they can leach contaminants into the environment.

What contaminants are of most concern in mining areas discussed in the script?

The primary contaminants of concern in these mining areas are arsenic and mercury. Both can occur naturally in the rocks, but mining activity increases their exposure to the environment, leading to higher concentrations of these toxic elements in water.

How does mercury contamination occur in mining, and why is it dangerous?

Mercury contamination can occur when mercury is used to amalgamate gold in artisanal mining practices, particularly in South America, Africa, and Asia. Additionally, mercury naturally present in rocks can be released during mining. Mercury is dangerous because it is toxic to humans and aquatic life, and it bioaccumulates up the food chain.

What are the typical arsenic levels in Nova Scotia, and how does mining influence these levels?

In Nova Scotia, naturally occurring arsenic levels are generally less than 25 micrograms per liter, with a range of 5 to 100 micrograms per liter. Mining activities, however, can increase arsenic concentrations to levels that are ten times higher than the natural background.

What are the environmental consequences of unlined impoundments in mining areas?

Unlined impoundments, where waste rock and tailings are stored, can lead to significant environmental problems. These impoundments allow contaminants like arsenic and mercury to leach into the environment, contaminating water sources and harming local ecosystems.

What were the findings of the 2006 study on predictions in Environmental Impact Statements (EIS) for water quality in mining?

The 2006 study reviewed 104 Environmental Impact Statements and found that 75% of them underestimated the impacts on water quality. In most cases, the EIS predicted that there would be no problem with exceeding water quality standards, but in reality, many of these mines exceeded the standards for aquatic life or drinking water.

What are the long-term environmental concerns associated with acid mine drainage?

Acid mine drainage presents a perpetual environmental concern because the acidic runoff can continue indefinitely, potentially for thousands of years. Mines from as far back as Roman times are still producing acid drainage today, requiring ongoing care, maintenance, and treatment to mitigate the environmental impact.