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

UNDERSTORY

25 Nov 201907:28

Summary

TLDRThe 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.

Outlines

00:00

👨‍🔬 Background and Expertise in Geochemistry

The speaker introduces themselves as an independent consultant based in Boulder, Colorado, with a PhD in geochemistry from Princeton University. With over 25 years of experience as a geochemist, they have worked as a researcher and for state, federal agencies, and environmental groups. Currently, they serve as the chief scientist for eTech International, a nonprofit working mostly in Latin America. Their expertise lies in analyzing tests on ore and waste materials to assess potential contaminants, offering insights into environmental concerns related to mining, especially acid mine drainage.

05:01

⛏️ The Impact of Acid Mine Drainage

Acid mine drainage is introduced as a significant environmental issue tied to hardrock (metal) mining. Historically, mining contamination has been problematic since the 1800s, with periods of gold rushes exacerbating the situation. The transition from underground to open-pit mining is highlighted, emphasizing that this more disruptive method leaves large quantities of waste on the surface, where contaminants like arsenic and mercury can leach into the environment. Once started, acid mine drainage becomes difficult to halt, posing long-term environmental threats.

💥 Open-Pit Mining: Environmental Consequences

Open-pit mining is described as more cost-effective but environmentally damaging compared to underground mining. Although the gold is in small veins better suited for underground methods, companies opt for open-pit excavation. The speaker highlights the main contaminants of concern: arsenic and mercury. Both occur naturally in the area, but mining disturbs these elements, causing them to leach into water systems. Mercury, once used in artisanal gold mining, and antimony, another toxic element, are particularly hazardous to human health and aquatic ecosystems, with naturally occurring levels already present in Nova Scotia.

🐟 Mercury Contamination and Its Impact on the Food Chain

The southern province has high levels of mercury in aquatic life, particularly bugs that are consumed by fish, which in turn are eaten by humans. This bioaccumulation up the food chain is concerning for both environmental and human health. The speaker emphasizes that digging up mercury-laden rocks and leaving them exposed on the landscape exacerbates the contamination issue. Without proper containment, mercury leaches into water bodies, leading to increased contamination of both wildlife and drinking water sources.

⏳ Long-Term Effects of Acid Drainage

Acid mine drainage, once it starts, requires perpetual care, maintenance, and treatment. Mines dating back to Roman times still produce acid today. The speaker underscores the long-term, unavoidable responsibility of managing these waste deposits. They mention a 2006 study, done with mining engineer Jim Kuipers, which reviewed environmental impact statements (EIS) for water quality predictions during mining activities and compared them with actual case studies. The findings revealed that 75% of mines underestimated the impact on water quality, often exceeding standards meant to protect aquatic life and drinking water.

Mindmap

Keywords

💡Geochemist

A geochemist studies the chemical composition of the Earth and its natural processes. In the video, the speaker mentions their background as a geochemist, working on analyzing ore and waste from mining operations to determine the contaminants that may be released into the environment, such as arsenic and mercury.

💡Acid mine drainage

Acid mine drainage refers to the outflow of acidic water from mines, especially metal mines. This process is a significant environmental problem linked to hardrock mining, as mentioned in the video. The speaker describes it as an auto-catalytic reaction that continues once it starts and poses long-term challenges for water quality, especially in areas like Nova Scotia.

💡Hardrock mining

Hardrock mining involves extracting metals like gold, copper, and lead from solid rock. The speaker discusses how this type of mining causes substantial environmental impacts, particularly through acid mine drainage, which releases contaminants into the surrounding water and soil. It contrasts with more traditional underground mining methods.

💡Open pit mining

Open pit mining is a method of extracting minerals by digging a large surface pit rather than tunneling underground. The speaker explains how this form of mining is more disruptive to landscapes, as it involves removing large amounts of rock and waste, which stay on the surface and contribute to environmental contamination, including leaching of harmful chemicals.

💡Contaminants

Contaminants are harmful substances that can enter the environment and cause pollution. In the context of the video, contaminants like arsenic, mercury, and antimony are released during mining operations. These elements occur naturally but are mobilized and become hazardous when disturbed by mining activities, threatening both human health and ecosystems.

💡Arsenic

Arsenic is a toxic element often found naturally in the environment, particularly in areas with gold deposits. The speaker highlights its significance as a major contaminant in mining regions, where its concentration in water can exceed safe levels for both aquatic life and humans, particularly when mining activities disturb arsenic-rich rocks.

💡Mercury

Mercury is a heavy metal that poses serious health risks, especially in mining areas where it is used or released. In the video, the speaker discusses mercury’s role in gold mining, particularly in artisanal mining in Latin America and Africa. Mercury contamination affects aquatic ecosystems and accumulates in the food chain, posing risks to fish and humans alike.

💡Environmental impact statements

Environmental impact statements are documents that assess the potential environmental consequences of proposed projects, such as mining operations. The speaker references a study that reviewed such statements for mines and found that 75% of them underestimated the impact on water quality, which resulted in significant harm to aquatic life and drinking water sources.

💡Perpetual care and maintenance

Perpetual care and maintenance refer to the long-term management and treatment required for mining sites, particularly those affected by acid mine drainage. The speaker emphasizes that once a mine is established and contamination begins, it often requires ongoing care indefinitely to prevent environmental damage, even long after mining has ceased.

💡Antimony

Antimony is a toxic metal-like substance that often occurs alongside arsenic in mining areas. The speaker explains its dangerous effects, particularly its high toxicity to humans and aquatic life, even at lower concentrations than arsenic. Like arsenic and mercury, antimony contamination poses serious risks in mining regions.

Highlights

The speaker is an independent consultant with a PhD in geochemistry from Princeton University, with over 25 years of experience working as a geochemist for various organizations including state and federal agencies.

The speaker is also the chief scientist for eTech International, a nonprofit organization focused on environmental work, primarily in Latin America.

Acid mine drainage (AMD) is described as the number one environmental water quality issue associated with hardrock mining (metal mining).

AMD is difficult to control once it starts because it is an autocatalytic reaction, making remediation challenging even after mining stops.

There has been a shift from underground mining to open-pit mining, which is more disruptive to landscapes and leaves large waste rock and tailings on the surface, leading to long-term contamination.

The main contaminants of concern in mining areas are arsenic and mercury, with naturally occurring levels in Nova Scotia that are sometimes amplified by mining activities.

Mercury is used in artisanal gold mining across South America, Africa, and Asia, posing a significant health risk to local communities.

Antimony, a metal-like substance similar to arsenic, is highly toxic to humans and aquatic life even at lower concentrations.

Naturally occurring arsenic in the environment is amplified in mining-influenced areas, leading to concentrations up to 10 times higher than usual.

Contaminants like arsenic, mercury, and antimony are found together in mining areas, posing a severe risk to local water systems, especially those supporting fisheries.

When rock is removed from the ground and placed in unlined impoundments, contaminants like mercury and arsenic begin leaching into the environment, creating long-term environmental issues.

There have been discoveries of extremely high mercury levels in aquatic bugs in Nova Scotia, which then move up the food chain, affecting fish and human health.

The unique water systems in the region, including salmon fisheries, are at high risk from acid mine drainage, making it essential to protect them from contamination.

Mines that produce acid drainage often require perpetual care, maintenance, and treatment to manage ongoing contamination. Some mines over 4,000 years old still produce acid drainage.

A 2006 study led by the speaker reviewed 104 environmental impact statements (EIS) for 471 large mines in the U.S., revealing that 75% of these projects underestimated their impact on water quality.