Effects of Gold Mines On Water Tables: Abridged Version #goldmines #environment #novascotia
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
- π§βπ¬ 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.
- βοΈ Acid mine drainage is the most significant environmental issue related to metal mining, and itβs a persistent problem, often resulting from large-scale open-pit mining.
- π 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.
- β οΈ Mercury and arsenic are the primary contaminants of concern in mining, particularly in areas like Nova Scotia where naturally occurring arsenic is already present.
- π 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.
- π‘ 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.
- π 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.
- π Water systems in regions with mining activity are vulnerable to contamination, threatening drinking water sources and fisheries, including salmon habitats.
- π οΈ 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.
- π 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
π¨βπ¬ 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.
βοΈ 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.
π₯ 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.
π 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.
β³ 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
π‘Geochemist
π‘Acid mine drainage
π‘Hardrock mining
π‘Open pit mining
π‘Contaminants
π‘Arsenic
π‘Mercury
π‘Environmental impact statements
π‘Perpetual care and maintenance
π‘Antimony
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.
Transcripts
want to give a little bit of background
on me I'm an independent consultant in
Boulder Colorado I've worked I've a PhD
in geochemistry from Princeton
University I've worked for over 25 years
as a geochemist as a researcher and also
for state and federal agencies and
environmental groups and I'm also chief
scientist for eTech International which
is a nonprofit organization working
mostly in Latin America so this is kind
of what I do and I'm a geochemist so I
look at the results of the tests that
they do on the ore and the waste that
comes out of the ground and depending on
the mineralogy and other things that
we'll talk a little bit about that can
give you an indication of the
contaminants that might come off of that
deposit okay so this is a picture of
acid mine drainage I don't know how many
of you have heard of this term before
but it's probably the number one
environmental water quality problem
associated with so called hardrock
mining which is you can think of as
metal mining okay and there's been a lot
of Unruh mediated contamination that's
come out of these deposits they were
also there was a gold rush in the kind
of 1860s 1870s timeframe there was
another one in kind of the 1970s 80s and
now there's another one so but the
remediation is still needed and acid
mine drainage once it starts it's very
difficult to turn it off it's what's
known as an auto catalytic reaction in
the 1800s and the 1980s etc that
everything was underground mining and
now they're starting open pit mining
which is a lot more disruptive to the
landscape
okay so rather than digging tunnels and
going down and you know pulling out
veins of ore they're just digging a
giant hole and taking everything out and
putting the waste rock and the tailings
you know on the surface of the earth and
they will stay there in perpetuity
leaching leaching contaminants
but all four of these are planned to be
open pit excavations even though the ore
is in these little veins that really
would be better developed as an
underground mine but it's cheaper for
the companies to do an open pit
excavation the main contaminants of
concern are arsenic and Mercury and
these mercury in the past has been used
to amalgam gold and if you've heard of
artisanal gold mining a lot of it
happens in South America Africa Asia
mercury is mixed with the gold ore and
then the gold goes into the mercury and
then you take the mercury and do a
retort which is basically you're heating
it up and a lot of the miners are just
you know people who are trying to make a
living very poor and then they're
exposed to the mercury and have a lot of
contamination in this case the mercury
and the arsenic are actually naturally
occurring with the rocks in the area you
have a not a lot of naturally occurring
arsenic in Nova Scotia the background
arsenic that means without mining is
generally less than 25 micrograms per
liter the range is five to a hundred
micrograms per liter and just for
comparison the aquatic life guidelines
are 5 micrograms per liter for health of
fish okay and for us for drinking water
it's 10 micrograms per liter so even in
areas that are not that influenced by
mining you do have some naturally
occurring arsenic in the rivers and in
groundwater in this area however if you
go to areas that are mining influence
the concentration is around 10 times
higher and if you look you get the same
exact location for arsenic antimony and
Mercury okay so arsenic occurs naturally
with the gold and then antimony is a
metal like kind of substance that is
similar to arsenic but it's incredibly
toxic to humans at even lower
concentrations than arsenic and it's
also toxic to aquatic biota
so in a community
or an area like this where the fishing
is incredibly important these are
important things to know about in your
water and then mercury there are very
high concentrations of mercury in the
same exact location so these are
naturally occurring if you leave them in
the ground you're not going to have much
of a problem however if you dig the rock
out of the ground cut it up into little
pieces and then you know put it on the
landscape in unlined impoundments then
you are gonna have a problem and there's
a researcher at st. Mary's University
they've found incredibly high levels of
mercury in aquatic bugs in that area in
the southern part of the province and
then the fish eat the bugs we eat the
fish etc and it goes up the food chain
this kind of information is important
because you have unique water here that
is not going to be able to handle acid
mine drainage coming into it and
protecting the salmon fishery your water
that you drink
etc so the other thing that I wanted to
mention is pretty much all the mines
that have acid drainage that make acid
drainage that is a perpetual care
maintenance and treatment situation we
have mines from 4,000 years ago
you know Roman times that are still
producing acid today so this perpetual
care maintenance and treatment when you
have a mine those are kind of three
different things the care and
maintenance is always there okay because
these waste deposits stay on the surface
forever okay in 2006 I did a study
within mining engineers named Jim
Kuiper's who's in Montana and we did a
really the kind of this study has never
been done before and or since we looked
at the predictions and environmental
impact statements for what the water
quality was going to be during mining
and then we looked at some case studies
to see what actually happened at the
mines so we reviewed 104 environmental
pack statements 471 large minds in the
US and we had you know a definition for
a large mind and we did this comparison
for 25 case studies
what was predicted versus what actually
happened and what we found was that 3/4
of them underestimated impacts to water
quality okay they said so in other words
they said in the environmental impact
statement we don't think there's gonna
be a problem
in the United States and probably here
too if you say we think there is going
to be a problem we're gonna exceed
standards we're gonna exceed standards
for protection of fish standards for
protection of potable water you won't
get a permit okay so they said we're
gonna be fine we don't have a problem
and then we looked and 75% of them
actually did exceed standards for
protection of aquatic life or drinking
water
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