Description
From 1904 to 1974, a mine operated at Britannia Beach, extracting the ores of copper, lead, zinc, gold, silver and cadmium. At its peak, the mine was the biggest copper producer in the British Commonwealth. The miners extracted enough ore to produce around 800,000 tonnes of metal, with most of that being copper. That 800,000 tonnes is roughly equal to the weight of 4000 jumbo jets.
BRITANNIA’S ENVIRONMENT
A look into the 20th century environmental legacy of the
Britannia Mine and its 21st century clean up
PAST • PRESENT • FUTURE
The Britannia Mine
From 1904 to 1974, a mine operated at
Britannia Beach, extracting the ores of
copper, lead, zinc, gold, silver and cadmium.
At its peak, the mine was the biggest copper
producer in the British Commonwealth. The
miners extracted enough ore to produce around
800,000 tonnes of metal, with most of that being
copper. That 800,000 tonnes is roughly equal to
the weight of 4000 jumbo jets.
There were 210 km (150 miles) of tunnels dug,
and the vertical shafts stretch from around 1300
m above sea level to around 650 m below sea
level. During the life of the mine, pollution from
mining was not tackled. On closing, Anaconda
(the then owners), took steps to divert the
pollution from the most sensitive environments
– in line with the environmental standards of
the day, but it did not stop the pollution. Over
the next thirty years, with no mine owners to
improve conditions, the pollution problem only
grew worse.
Acid Rock Drainage
Acid Rock Drainage (ARD) is a natural process
that happens when metal sulphides are
exposed to oxygen and water – air and rain -
though bacteria (Thiobacillus ferrooxidans) also
play a big part in ARD production. The biggest
ARD producer is pyrite (iron sulphide), though
at Britannia, others include chalcopyrite (the
copper ore), galena (lead) and sphalerite (zinc).
A chemical reaction happens that produces
sulphuric acid and dissolves metals, both of
which pollute the local environment when
they get into the groundwater and local water
sources.
ARD production is a very complicated process,
but the main reaction is:
2FeS2(s) + 7O2(g) + 2H2O(l) --> 2Fe2+(aq) + 4SO42-(aq) + 4H+(aq)
pyrite + oxygen + water --> ferrous iron + sulphate + hydrogen
The site of the Britannia Mine. Circa 1960
The Size of the Problem
Because the ARD-forming chemical reaction
needs air and water to work, ARD generation
increases as surface area of the metal sulphides
increases. ARD formed at Britannia before the
mine ever existed, but only within exposed
surface and near surface mineralized rock.
The mine created surface area from 210 km
of tunnels. High snow and rainfall has sent
large volumes of water flowing through the old
tunnels and seeping through the fractured rock
that has been shattered by mining operations.
This has resulted in the formation of ARD - the
water can flow from the mine at up to 3600 cubic
metres per hour. When the ARD exited the mine,
it flowed into local creeks and Howe Sound.
This led to Britannia Beach becoming seriously
polluted – an average of 600 kg of dissolved
metals were being washed into Howe Sound
each day, making it harmful to aquatic life.
The History of the Problem
In the 1930s, it was known that the mine
water was acidic and contained dissolved
metals, though little
was understood
about the
environmental impacts. From the 1930’s to the
1970’s, copper launders helped, but these were
for economic, not environmental reasons. The
launders were long timber or concrete troughs
containing iron scraps. The mine water was fed
through these before being discharged. An iron-
copper exchange happened; copper coated the
iron scraps and dissolved, relatively non-toxic
iron flowed with the water out of the troughs.
The copper flaked off from the scraps and was
collected to be sold. So it did help reduce the
amount of copper entering Howe Sound, but
after the mine closed in 1974, the use of the
launders soon stopped.
Anaconda, the last operating owners, had
planned to build a lime treatment plant, but it
was never built as the mine closed. On closure,
they installed an outflow pipe that discharged
the water 50 m below sea level. The water
was not treated, but was taken away from the
intertidal zone, the most vulnerable area for
aquatic life. They also installed an underground
mud/earth dam near the 2200 Level portal, to
prevent water exiting the mine at this point.
This stopped mine water entering Britannia
Creek, though the dam failed sometime in the
1980’s/90’s.
The BC Province Intervenes
In 1997 with the introduction of the Contaminated
Sites Regulation, the Province began the site’s
remediation. In 2001, they secured $30 million
from ‘Potentially Responsible Persons’ – former
owners and the present owners of former
owners. In the same year they appointed Golder
Associates to assess and plan the remediation.
In 2003, in a mutual agreement, the Province took
control of the majority of the mine site from the
land owners. By 2004 they had appointed EPCOR
to build and operate the Water Treatment Plant
under a P3 contract (Public-Private Partnership).
The facility was operating by October 2005.
The local creeks eventually became contaminated
with iron hydroxide coatings called ‘yellowboy’
Water Treatment In Action - Collecting Water
Even though there were 210 km of tunnels, there
were only ever a few portals and shafts (mine
entrances). These are now blocked or orientated
in a way that all the water is diverted to the 4100
Level portal next to the Water Treatment Plant.
The mine now acts as a giant reservoir, capable
of storing up to 430,000 cubic metres of water. At
this portal, an 8 m thick concrete plug, outflow
pipes and a valve system carefully control water
flow from the mine to the treatment facility.
Water Treatment In Action - Treating the Water
On arrival at the facility, the water is first
treated with lime slurry (a mixture of lime
and water) in two reactor tanks. The alkaline
lime neutralizes the acidic water, quickly
raising the pH from 3.8 (ARD) to 9.3. At pH 8.5,
the dissolved metals naturally come out of
solution and precipitate as tiny particles. The
most amount of metals precipitate at pH 9.3.
The water is then fed into a large ‘clarifier’ tank
where a customized, man-made polymer is
added. This electrostatically attracts the metal
particles, forming clumps that sink through
their own weight, creating a dense sludge at
the bottom of the tank. This is removed, and
the clean water is discharged into Howe Sound.
By the time the water reaches the sea, its pH
has naturally decreased to around neutral.
Some of the metal-rich sludge is added
back into the lime and ARD mix. The sludge
particles are a catalyst, encouraging the newly
precipitated metals to stick to them – speeding
up the precipitation/ clumping process.
The rest of the sludge is dewatered in a large
filter press (to 45% dry), then stored until
it is taken back up to the original mining
pit (Jane Basin) high on the mountain.
The Metal Sludge
The water treatment process removes around
600 – 700 kg of metal sludge every day. The main
metals removed are aluminum, zinc, copper,
manganese, iron and cadmium. This is around
95% of the metal in the water.
The sludge is stored on site until it can be taken
up to the Jane Basin mining pit, where it helps
cap the pit. As the metals are no longer in the
form of a metal sulphide, they won’t react with
air and water to form ARD. Also, as the pH is
now slightly alkaline, any water runoff into the
mine will help to neutralize the acidic water in
the mine.
Water sampling from Britannia Creek
Storing the metal sludge before transport to the
Jane Basin pit
EPCOR Britannia Mine Water Treatment Plant
Contaminated Soils
The soils around the 2200 Level portal at the
old Mount Sheer townsite and on the fan at
Britannia Beach, have been badly contaminated
by mining operations. The alluvial fan area at
Britannia Beach is largely overlain by tailings
(waste rock) from the Mill operations. This has
contributed to the contamination of the ground
here. The worst of the soil has been removed
to the original Jane Basin mining pit. Here, any
ARD it generates will be captured in the mine
and then cleaned by the water treatment plant.
Currently about 50% of the ARD generated by
the remaining contaminated soils is captured by
the wells on the foreshore and pumped to the
water treatment plant. Ongoing work aims to
take this to over 90%.
There are also tailings located offshore in Howe
Sound at Britannia Beach. These are considered
to be low risk because of the lack of oxygen
needed for the chemical reactions, and because
they are slowly being covered by silt flowing into
Howe Sound from the Squamish River.
The Outcome
As long as the Water Treatment Plant is
operating and the 2200
Level plug is in
place, the
water
that flows from the mine into Howe Sound
will be clean. The operators run daily tests on
the treated water, and weekly tests go to an
independent lab. To date, no results have failed
the stringent levels set by the Province.
Statistically, there is a long term, small chance
that extreme weather/climates could prove too
much for the facility. In such a case it may be
necessary to discharge some of the water to
Howe Sound quickly, treating it only with lime;
this would need to be authorized by the Province.
To avoid such an event, the operators make
allowances for likely conditions. For example,
before freshet, they process as much water as
possible to lower the level of the reservoir.
Life Returns
In the few short years that the remediation
campaign has been taking place, Golder
Associates have been monitoring the shoreline
at Britannia for dissolved metal levels and for its
ecology. There are currently still some hot-spots
- the focus for future work, but the shoreline
and sea water quality has improved greatly and
life has returned. In 2011, both Pink and Coho
salmon were also found to be swimming in
the lower reaches of Britannia Creek.
Drilling groundwater pumping wells at the Museum
Monitoring life on the shores of Howe Sound
More Information
www.epcor.com
www.britanniamine.ca
To find out more about the Britannia Mine’s
history, visit - www.britanniaminemuseum.ca
Acknowledgment goes to EPCOR and Golder
Associates (on behalf of the Britannia
Remediation Project) for permission to use their
photographs
Key Dates
1904 Mine opens
1920’s Largest copper mine in British Empire:
mine operators are aware of pH levels
and metal contaminants but not
required to take action
1974 Mine closes; Anaconda build discharge
pipe below sea level and small dam at
2200 portal to direct water to 4100 portal
1970’s Late 70’s, concrete plug and outflow pipe
built at 4100 portal to flow through plug
in controlled manner
1979 Mine sold to real estate developer
(Copper Beach Estates)
1981 Pollution control not being maintained;
start of monitoring and studies
1997 Start to test and design treatment plant
1997 Contaminated Sites Regulation effective
2001 $30 million settlement
2001 UBC installs concrete plug at 2200 portal
2002 Golder Associates appointed Province to
assess situation and plan remediation
2003 Agreement with new land owner
(MacDonald Development Corporation)
to take control of site
2005 EPCOR awarded contract; construction
begins in April and operating in October
Britannia Creek - clean once again
How the pollution has been addressed:
1. Plug prevents ARD leaving 2200 portal
2. ARD collected at 4100 portal and treated by Water
Treatment Plant
3. Groundwater collected on foreshore and pumped to WTP
4. Original mining pit being slowly partly capped by rock
waste and sludge from treatment process
doc_942895992.pdf
From 1904 to 1974, a mine operated at Britannia Beach, extracting the ores of copper, lead, zinc, gold, silver and cadmium. At its peak, the mine was the biggest copper producer in the British Commonwealth. The miners extracted enough ore to produce around 800,000 tonnes of metal, with most of that being copper. That 800,000 tonnes is roughly equal to the weight of 4000 jumbo jets.
BRITANNIA’S ENVIRONMENT
A look into the 20th century environmental legacy of the
Britannia Mine and its 21st century clean up
PAST • PRESENT • FUTURE
The Britannia Mine
From 1904 to 1974, a mine operated at
Britannia Beach, extracting the ores of
copper, lead, zinc, gold, silver and cadmium.
At its peak, the mine was the biggest copper
producer in the British Commonwealth. The
miners extracted enough ore to produce around
800,000 tonnes of metal, with most of that being
copper. That 800,000 tonnes is roughly equal to
the weight of 4000 jumbo jets.
There were 210 km (150 miles) of tunnels dug,
and the vertical shafts stretch from around 1300
m above sea level to around 650 m below sea
level. During the life of the mine, pollution from
mining was not tackled. On closing, Anaconda
(the then owners), took steps to divert the
pollution from the most sensitive environments
– in line with the environmental standards of
the day, but it did not stop the pollution. Over
the next thirty years, with no mine owners to
improve conditions, the pollution problem only
grew worse.
Acid Rock Drainage
Acid Rock Drainage (ARD) is a natural process
that happens when metal sulphides are
exposed to oxygen and water – air and rain -
though bacteria (Thiobacillus ferrooxidans) also
play a big part in ARD production. The biggest
ARD producer is pyrite (iron sulphide), though
at Britannia, others include chalcopyrite (the
copper ore), galena (lead) and sphalerite (zinc).
A chemical reaction happens that produces
sulphuric acid and dissolves metals, both of
which pollute the local environment when
they get into the groundwater and local water
sources.
ARD production is a very complicated process,
but the main reaction is:
2FeS2(s) + 7O2(g) + 2H2O(l) --> 2Fe2+(aq) + 4SO42-(aq) + 4H+(aq)
pyrite + oxygen + water --> ferrous iron + sulphate + hydrogen
The site of the Britannia Mine. Circa 1960
The Size of the Problem
Because the ARD-forming chemical reaction
needs air and water to work, ARD generation
increases as surface area of the metal sulphides
increases. ARD formed at Britannia before the
mine ever existed, but only within exposed
surface and near surface mineralized rock.
The mine created surface area from 210 km
of tunnels. High snow and rainfall has sent
large volumes of water flowing through the old
tunnels and seeping through the fractured rock
that has been shattered by mining operations.
This has resulted in the formation of ARD - the
water can flow from the mine at up to 3600 cubic
metres per hour. When the ARD exited the mine,
it flowed into local creeks and Howe Sound.
This led to Britannia Beach becoming seriously
polluted – an average of 600 kg of dissolved
metals were being washed into Howe Sound
each day, making it harmful to aquatic life.
The History of the Problem
In the 1930s, it was known that the mine
water was acidic and contained dissolved
metals, though little
was understood
about the
environmental impacts. From the 1930’s to the
1970’s, copper launders helped, but these were
for economic, not environmental reasons. The
launders were long timber or concrete troughs
containing iron scraps. The mine water was fed
through these before being discharged. An iron-
copper exchange happened; copper coated the
iron scraps and dissolved, relatively non-toxic
iron flowed with the water out of the troughs.
The copper flaked off from the scraps and was
collected to be sold. So it did help reduce the
amount of copper entering Howe Sound, but
after the mine closed in 1974, the use of the
launders soon stopped.
Anaconda, the last operating owners, had
planned to build a lime treatment plant, but it
was never built as the mine closed. On closure,
they installed an outflow pipe that discharged
the water 50 m below sea level. The water
was not treated, but was taken away from the
intertidal zone, the most vulnerable area for
aquatic life. They also installed an underground
mud/earth dam near the 2200 Level portal, to
prevent water exiting the mine at this point.
This stopped mine water entering Britannia
Creek, though the dam failed sometime in the
1980’s/90’s.
The BC Province Intervenes
In 1997 with the introduction of the Contaminated
Sites Regulation, the Province began the site’s
remediation. In 2001, they secured $30 million
from ‘Potentially Responsible Persons’ – former
owners and the present owners of former
owners. In the same year they appointed Golder
Associates to assess and plan the remediation.
In 2003, in a mutual agreement, the Province took
control of the majority of the mine site from the
land owners. By 2004 they had appointed EPCOR
to build and operate the Water Treatment Plant
under a P3 contract (Public-Private Partnership).
The facility was operating by October 2005.
The local creeks eventually became contaminated
with iron hydroxide coatings called ‘yellowboy’
Water Treatment In Action - Collecting Water
Even though there were 210 km of tunnels, there
were only ever a few portals and shafts (mine
entrances). These are now blocked or orientated
in a way that all the water is diverted to the 4100
Level portal next to the Water Treatment Plant.
The mine now acts as a giant reservoir, capable
of storing up to 430,000 cubic metres of water. At
this portal, an 8 m thick concrete plug, outflow
pipes and a valve system carefully control water
flow from the mine to the treatment facility.
Water Treatment In Action - Treating the Water
On arrival at the facility, the water is first
treated with lime slurry (a mixture of lime
and water) in two reactor tanks. The alkaline
lime neutralizes the acidic water, quickly
raising the pH from 3.8 (ARD) to 9.3. At pH 8.5,
the dissolved metals naturally come out of
solution and precipitate as tiny particles. The
most amount of metals precipitate at pH 9.3.
The water is then fed into a large ‘clarifier’ tank
where a customized, man-made polymer is
added. This electrostatically attracts the metal
particles, forming clumps that sink through
their own weight, creating a dense sludge at
the bottom of the tank. This is removed, and
the clean water is discharged into Howe Sound.
By the time the water reaches the sea, its pH
has naturally decreased to around neutral.
Some of the metal-rich sludge is added
back into the lime and ARD mix. The sludge
particles are a catalyst, encouraging the newly
precipitated metals to stick to them – speeding
up the precipitation/ clumping process.
The rest of the sludge is dewatered in a large
filter press (to 45% dry), then stored until
it is taken back up to the original mining
pit (Jane Basin) high on the mountain.
The Metal Sludge
The water treatment process removes around
600 – 700 kg of metal sludge every day. The main
metals removed are aluminum, zinc, copper,
manganese, iron and cadmium. This is around
95% of the metal in the water.
The sludge is stored on site until it can be taken
up to the Jane Basin mining pit, where it helps
cap the pit. As the metals are no longer in the
form of a metal sulphide, they won’t react with
air and water to form ARD. Also, as the pH is
now slightly alkaline, any water runoff into the
mine will help to neutralize the acidic water in
the mine.
Water sampling from Britannia Creek
Storing the metal sludge before transport to the
Jane Basin pit
EPCOR Britannia Mine Water Treatment Plant
Contaminated Soils
The soils around the 2200 Level portal at the
old Mount Sheer townsite and on the fan at
Britannia Beach, have been badly contaminated
by mining operations. The alluvial fan area at
Britannia Beach is largely overlain by tailings
(waste rock) from the Mill operations. This has
contributed to the contamination of the ground
here. The worst of the soil has been removed
to the original Jane Basin mining pit. Here, any
ARD it generates will be captured in the mine
and then cleaned by the water treatment plant.
Currently about 50% of the ARD generated by
the remaining contaminated soils is captured by
the wells on the foreshore and pumped to the
water treatment plant. Ongoing work aims to
take this to over 90%.
There are also tailings located offshore in Howe
Sound at Britannia Beach. These are considered
to be low risk because of the lack of oxygen
needed for the chemical reactions, and because
they are slowly being covered by silt flowing into
Howe Sound from the Squamish River.
The Outcome
As long as the Water Treatment Plant is
operating and the 2200
Level plug is in
place, the
water
that flows from the mine into Howe Sound
will be clean. The operators run daily tests on
the treated water, and weekly tests go to an
independent lab. To date, no results have failed
the stringent levels set by the Province.
Statistically, there is a long term, small chance
that extreme weather/climates could prove too
much for the facility. In such a case it may be
necessary to discharge some of the water to
Howe Sound quickly, treating it only with lime;
this would need to be authorized by the Province.
To avoid such an event, the operators make
allowances for likely conditions. For example,
before freshet, they process as much water as
possible to lower the level of the reservoir.
Life Returns
In the few short years that the remediation
campaign has been taking place, Golder
Associates have been monitoring the shoreline
at Britannia for dissolved metal levels and for its
ecology. There are currently still some hot-spots
- the focus for future work, but the shoreline
and sea water quality has improved greatly and
life has returned. In 2011, both Pink and Coho
salmon were also found to be swimming in
the lower reaches of Britannia Creek.
Drilling groundwater pumping wells at the Museum
Monitoring life on the shores of Howe Sound
More Information
www.epcor.com
www.britanniamine.ca
To find out more about the Britannia Mine’s
history, visit - www.britanniaminemuseum.ca
Acknowledgment goes to EPCOR and Golder
Associates (on behalf of the Britannia
Remediation Project) for permission to use their
photographs
Key Dates
1904 Mine opens
1920’s Largest copper mine in British Empire:
mine operators are aware of pH levels
and metal contaminants but not
required to take action
1974 Mine closes; Anaconda build discharge
pipe below sea level and small dam at
2200 portal to direct water to 4100 portal
1970’s Late 70’s, concrete plug and outflow pipe
built at 4100 portal to flow through plug
in controlled manner
1979 Mine sold to real estate developer
(Copper Beach Estates)
1981 Pollution control not being maintained;
start of monitoring and studies
1997 Start to test and design treatment plant
1997 Contaminated Sites Regulation effective
2001 $30 million settlement
2001 UBC installs concrete plug at 2200 portal
2002 Golder Associates appointed Province to
assess situation and plan remediation
2003 Agreement with new land owner
(MacDonald Development Corporation)
to take control of site
2005 EPCOR awarded contract; construction
begins in April and operating in October
Britannia Creek - clean once again
How the pollution has been addressed:
1. Plug prevents ARD leaving 2200 portal
2. ARD collected at 4100 portal and treated by Water
Treatment Plant
3. Groundwater collected on foreshore and pumped to WTP
4. Original mining pit being slowly partly capped by rock
waste and sludge from treatment process
doc_942895992.pdf