Volume 11, Number 2 (FALL 2006)
|
Q: |
What is the current water level
of the Pit? |
|
A: |
As of October 2, 2006,
the Pit's water level was 5,261.81 feet above sea level. The
water level climbed about 3.04 feet since the last issue of PitWatch
in Spring 2006. Since June 1996, when PitWatch was first published,
the water has risen about 134 feet. |
Volume 11, Number 1 (SPRING 2006)
|
Q: |
What is the current water level
of the Pit? |
|
A: |
As of April 6, 2006, the
Pit's water level was 5,258.77 feet above sea level. The water
level climbed about 3.97 feet since the last issue of PitWatch
in Fall 2005. Since June 1996, when PitWatch was first published,
the water has risen about 131 feet. |
|
Q: |
Is the water level in the Pit
rising according to predictions? |
|
A: |
The most recent evaluation
of monitoring data confirms previous predictions that it will
be approximately 2020 when water levels will approach the critical
level of 5,410' above sea level. The current model and prediction
assumes the amount of water flowing to the Pit will stay fairly
constant - enough water to raise the level in the Pit about six
to eight inches per month.
Also, data indicate that the water level at the Anselmo shaft
is still the highest among all the monitoring points in the program,
which means it will be used as the trigger to operate the treatment
plant at full capacity. As shown on the timeline,
a design assessment must be completed four years before the water
level in any of the designated wells or shafts is expected to
reach 5,410' and the treatment plant must be ready to operate
two years ahead of time. This timeline is reviewed and evaluated
every year and updated as needed. See timeline. |
|
Q: |
How is the Horseshoe Bend Water
Treatment Plant operating? |
|
A: |
In the six months since
the last edition of PITWATCH, the amount of water treated at
the plant has increased - from about two million gallons per
day to an average of about 3.4 million gallons per day. The reasons
for the increase - it appears the drought has finally ended and
the Yankee Doodle Tailings Ponds (north of the plant) have fully
recharged, after being dried out during the mine suspension from
2000-2003, and there's more water runoff coming from the Horseshoe
Bend flow.
All treated water is
still being used in mine operations, as makeup water at the concentrator,
and the residual sludge from the treatment process is still being
piped to the Berkeley Pit at a rate of 250,000 gallons per day.
No water is discharged to Silver Bow Creek. In general, operations
are going as expected. |
Volume 10, Number 2 (FALL 2005)
|
Q: |
What is the current water level
of the Pit? |
|
A: |
As of October 5, 2005,
the Pit's water level was 5,254.80 feet above sea level. The
water level climbed about 3.37 feet since the last issue of PitWatch
in Spring 2005. Since June 1996, when PitWatch was first published,
the water has risen about 127 feet. |
|
Q: |
Is the water level in the Pit
rising according to the predictions? |
|
A: |
For the past few years,
the water level continues to rise slightly slower - about six
to eight inches per month - than was expected. Back in the early
1990s, the average monthly water-level rise was about 24 inches
per month, and once the Horseshoe Bend Drainage water diversion
was installed in 1996, the rate dropped to about 12 inches per
month.
However, when Montana Resources suspended operations in June
of 2000, the Horseshoe Bend drainage water was allowed to flow
into the Pit, increasing the monthly rate of rise to 15-18 inches.
With the Horseshoe Bend water being diverted away from the Pit
since November 2003 (when mining resumed), the monthly water-level
rise has again been between six and eight inches most months.
Montana Resources staff point to the continuing drought in the
Butte area as one reason for the slower rate of rise. They've
revised their predictions annually, and if less water continues
flowing to the Pit, the Critical Water Level (5,410' above sea
level) would not be reached until December 2020, about 2½
years later than predicted. See timeline. |
|
Q: |
How is the Horseshoe Bend Water
Treatment Plant operating? |
|
A: |
Throughout 2005, the plant
has been used to process about two million gallons of water per
day. All treated water is being used as makeup water in the Montana
Resource concentrator, and the small amount of sludge produced
is being piped to the Berkeley Pit. No water is discharged to
Silver Bow Creek.
In general, operations are going well. There was a minor problem
this past summer with a recurring increase in torque in the massive
rake arm in one of two large clarifier tanks where the metal
sludge settles out. The manufacturer was called in, and after
realigning all the parts, reported that the range of torque increase
is not significant and will not reduce the life of the clarifier.
The downtime of this investigation also provided an opportunity
to complete some general maintenance - to replace the feedwell
seals and repair a few small areas of corrosion. As this work
was done, water was still being treated in the other clarifier
tank and delivered to MR for mining operations.
It should also be noted that the Record of Decision requires
that the treatment plant must be ready to operate at full capacity
(i.e., 7 million gallons per day) at least two years before the
water in the Pit approaches 5,410 feet. |
Volume 10, Number 1 (SPRING 2005)
|
Q: |
What is the current water level
of the Pit? |
|
A: |
As of April 6, 2005, the
Pit's water level was 5,251.43 feet above sea level. The water
level climbed about 3.65 feet since the last issue of PitWatch
in Fall 2004. Since June 1996, when PitWatch was first published,
the water has risen about 123.15 feet. |
|
Q: |
Is the water level in the Pit
rising according to predictions set forward in the 1994 Record
of Decision? |
|
A: |
No, the water level has
been rising slower than predicted. For the past 16 months, the
average monthly water level rise has been 0.65 feet comapred
to a rise of 2 feet per month in the mid-1990s.
One factor affecting the change in the rate of rise is the continuing
drought. Other previously predicted factors that influence the
declining rate of rise include the diversion of the Horseshoe
Bend Drainage water and the widening circumference of the pit. |
|
Q: |
How will this slower rate of
rise affect the future? |
|
A: |
No, the water level has
been rising slower than predicted. For the past 16 months, the
average monthly water level rise has been 0.65 feet comapred
to a rise of 2 feet per month in the mid-1990s.
One factor affecting the change in the rate of rise is the continuing
drought. Other previously predicted factors that influence the
declining rate of rise include the diversion of the Horseshoe
Bend Drainage water and the widening circumference of the pit. |
|
Q: |
How is the Horseshoe Bend Water
Treatment Plant operating? |
|
A: |
It is operating as designed.
It came on line in November 2003. The $18 million facility is
removing metals from the roughly 2 million gallons of water per
day flowing from Horseshoe Bend.
About 10 tons of lime is used per day. The treated water is being
routed for use in the milling operations at Montana Resources,
thus there is no discharge to Silver Bow Creek. A 4-inch sludge
discharge pipeline runs to the Berkeley Pit. As the critical
water level nears, the Plant will also start treating the Berkeley
Pit Water. |
Volume 9, Number 2 (FALL 2004)
|
Q: |
What is the current water level
of the Pit? |
|
A: |
As of late September 2004,
the Pit's water level was 5,247.78 feet above sea level. The
water level climbed about 3.5 feet since the last issue of PitWatch
in Spring 2004. Since June 1996, when PitWatch was first published,
the water has risen about 119.5 feet. |
|
Q: |
Is the water level in the Pit
rising according to predictions set forward in the 1994 Record
of Decision? |
|
A: |
No, the water level has
been rising less than predicted. Taking into account the widening
circumference of the Pit, and Montana Resources using Horseshoe
Bend water for mining, the rate of rise has been well under one
foot per month, which is about half of the predicted rate.
Officials suggest that the rate of rise has probably been slower
than predicted in the past six months due to drought conditions
that have caused lower inflows and higher evaporation rates. |
|
Q: |
How is the Horseshoe Bend Water
Treatment Plant operating? |
|
A: |
It is operating as designed.
It came on line in November 2003. The $18 million facility is
removing metals from the roughly 2 million gallons of water per
day flowing from Horseshoe Bend.
About 10 tons of lime is used per day. The treated water is being
routed for use in the milling operations at Montana Resources,
thus there is no discharge to Silver Bow Creek. A 4-inch sludge
discharge pipeline runs to the Berkeley Pit. As the critical
water level nears, the Plant will also start treating the Berkeley
Pit Water. |
|
Q: |
Is Montana Resources "mining"
the Berkeley Pit water? |
|
A: |
Yes. The company is still
recovering copper from the water in the Berkeley Pit.
Since February 2004, 13 million gallons of water per day are
being pumped out of the Berkeley Pit and up to the precipitation
plant. The water is collected at a depth of 150 feet from the
far west side of the Pit below the viewing stand, and is pumped
up and around the south and east walls of the Pit to the precipitation
plant, north east of the Pit.
The "Precip Plant" uses a centuries-old technology
operation where water flows through piles of recycled scrap iron.
The process is known as "cementation." It occurs when
copper-containing water flows into cells filled with scrap iron.
The iron in the cells and the copper in the water trade places.
The iron-rich water is returned to the Pit. The product, containing
about 70% copper, is dried through a filter press and then sent
to an off-site smelter. |
|
Q: |
What is the waterfall on the
northeast wall of the pit? |
|
A: |
Historically the waterfall
was created by the Horseshoe Bend flow north of the Berkeley
Pit, but that water is now treated and used in MR operations.
Since February 2004, water returning to the pit from the "Precip
Plant" forms the waterfall. |
Volume 9, Number
1 (SPRING 2004)
|
Q: |
What is the current water level
of the Pit? |
|
A: |
As of March 31, 2004,
the Pit's water level was 5,244.25 feet above sea level. The
water level climbed about five feet since the last issue of PitWatch
in Fall 2003, or a little less than one foot per month.
The decrease in the rate of rise is caused by the diversion and
use of Horseshoe Bend water in the resumption of mining by Montana
Resources. Since June 1996, when the PitWatch was first published,
the water has risen about 116 feet. |
|
Q: |
Is the water level in the Pit
rising according to predictions in the Record of Decision in
1994? |
|
A: |
Yes. Now that the mine has resumed operations
and the Horseshoe Bend Water Treatment Plant is operational the
rate of rise has slowed. As a result the water level is rising
according to predictions in the 1994 Record of Decision.
Back to top |
Volume 8,
Number 2 (FALL 2003)
|
Q: |
What is the current water level of
the Pit? |
|
A: |
Note: This question is answered
in every issue of PitWatch. We will always show the latest
data on PitWatch.org. You can also always find the current water
level below the navigation bar in the right-hand corner on every
PitWatch.org page.
At the end of September 2003 the Pit's water level was 5,239.47
feet above sea level. The water level climbed about seven feet
since the last issue of PitWatch in April 2003, or about
one foot per month. Since June 1996, when the PitWatch
was first published, the water has risen about 111 feet, and
since June 30, 2000, when the mine suspended operations, the
water has risen 56 feet. |
|
Q: |
Is the water level in the Pit
rising according to predictions in the Record of Decision in
1994? |
|
A: |
No. Since Montana Resources suspended mining,
more water has been entering the Berkeley Pit today than was
predicted in 1994. The extra water -- about 2 million gallons
a day (1,400 gallons a minute)-- came from the Horseshoe Bend
flow, which had been diverted (since 1996) from the Berkeley
Pit under an EPA order to reduce the rate of rise. However, the
mine has now resumed operations and the Horseshoe Bend Water
Treatment Plant is operational. As a result, the rate of rise
will slow.
Back to top |
Volume
8, Number 1 (SPRING 2003)
|
Q: |
What is the current water level of
the Pit? |
|
A: |
Note: This question is answered
in every issue of PitWatch. We will always show the latest
data on PitWatch.org. You can also always find the current water
level below the navigation bar in the right-hand corner on every
PitWatch.org page.
When last measured on April 4, 2003, the Pit's water level was
5,232.91 feet above sea level. The water level climbed about
seven feet since the last issue of PitWatch in October
2002, or about one foot per month. Since June 1996, when the
first PitWatch was published, the water has risen about
104 feet, and since 2000, after the mine suspended operations,
the water has risen about 49 feet. |
|
Q: |
Is the water level in the Pit
rising according to predictions in the Record of Decision in
1994? |
|
A: |
No. Since Montana Resources suspended mining
June 30, 2000, more water has been entering the Berkeley Pit
today than was predicted in 1994. The extra water - about 2 million
gallons a day - is coming from the Horseshoe Bend flow, which
had been diverted (since 1996) from the Berkeley Pit under an
EPA order to reduce the rate of rise. Until the Horseshoe Bend
Water Treatment Facility is operating (December 2003), the water
level in the Berkeley will be rising faster than originally predicted.
Back to top |
Volume
7, Number 2 (FALL 2002)
Questions from Website Users
Over the past six months, the
Committee has received several questions from people who have
turned to this web site for information about the Berkeley Pit.
Below are excerpts from a few of their questions and the answers
that may be of interest to others.
Wayne E. Halvorsen, Butte,
MT, writes: "What is going to happen to the old creek bottom
that runs from Continental Drive…to Montana Street…
a lot of kids ride bikes and play down there…there is a
lot of dust… is it safe?
Before the Berkeley Pit was
around, that old creek bottom was the main channel of Silver
Bow Creek, and recent studies indicate the creek corridor and
surrounding land does contain mine tailings. A final decision
on how to reclaim the area will be made in the next few years.
It is expected that some or all of the tailings along the creek
channel will be removed, and then a safe soil and vegetation
cap will be installed to eliminate exposure to any heavy metals.
Until that cleanup is complete, it's safer to discourage children
from playing in the area.
Nora Hanson, United World
College, New Mexico, writes: "...where can I find more information
about alternative clean-up methods that were presented for consideration
concerning the Pit…"
Several technologies were considered
before the Agencies approved the selected method to treat water
from the Berkeley Pit. The official Feasibility Study for this
Superfund site detailed a number of water treatment technologies
for the Pit and provided thorough evaluations of the pro and
cons of each cleanup method. Since then, many organizations and
companies have conducted a variety of research projects on alternative
clean-up methods. Examples of groups that have recently requested
water from the Pit (through the Montana Bureau of Mines and Geology
in Butte) to support their research include:
EPA National Risk Management Research Laboratory (Cincinnati,
OH): treatability studies focused on product recovery;
MSE (Butte, MT): treatability studies associated with the Horseshoe
Bend treatment plant;
Montana Tech (Butte, MT): various research projects;
Ion Resolution (Virginia City, MT): treatability studies focused
on product recovery;
Virotec (Australia): treatability studies using Bauxsol;
ASARCO Technology Research Center (Salt Lake City);
Wilder Construction (Everett, WA); and
Frontier Geosciences (Seattle, WA).
For more information, visit the website of the EPA's Mine Waste
Technology Program at the following address:
www.epa.gov/ordntrnt/ORD/NRMRL/std/mtb/mwtphome.html
Also look for related links
from that site.
Brian Varner, Butte,
MT, writes: "…I live up on the East Ridge and have
a well for drinking water. I have noticed my well water does
not seem to be as fresh as it once was… Could the Pit have
any bearing…?"
There is no connection between
the Berkeley Pit water and your well water. The water levels
in the Berkeley Pit (currently at an elevation of 5,225 ft) and
the flooding underground mines are well below the lowest ground-water
levels in the entire Butte Basin. The Berkeley Pit is the "sink"
or lowest water-level point in the basin, and all ground water
near the pit is trying to flow towards the "sink".
Water levels in alluvial aquifers (within the valley) are generally
several hundred feet or more above the pit level, while water
levels in the bedrock (along the East Ridge and foothills south
of Butte) are a hundred or more feet above the pit level. Water
quality monitoring of bedrock wells surrounding the pit continue
to show that wells outside the area are not being impacted by
rising pit and mine water levels.
Volume
7, Number 1 (SPRING 2002)
|
Q: |
Is the water level in the Pit
rising faster since mining was suspended? |
|
A: |
Yes. Since Montana Resources suspended mining
June 30, 2000, more water - about three million gallons per day
- has been entering the Berkeley Pit, mostly from the Horseshoe
Bend flow that used to be diverted to the mine operations. Instead
of rising about one foot per month, the water level has been
going up about 1.5 feet per month.
Back to top |
|
Q: |
What is being done to deal
with the extra water? |
|
A: |
In March 2002, the Atlantic Richfield Company
and Montana Resources agreed to start construction of a treatment
plant for the Horseshoe Bend water. The commitment is part of
a Consent Decree that guarantees the plant will be operating
by August 2003 (unless Montana Resources starts up again before
June 30, 2002). With the plant up and running, the extra water
will once again be diverted from the Berkeley Pit, and the water
will rise at a slower rate.
Back to top |
|
Q: |
Could the Horseshoe Bend facility
eventually be used to treat Berkeley Pit water? |
|
A: |
Yes. The Horseshoe Bend facility has been designed
so that it will require only minor changes and upgrades to also
treat the water from the Berkeley Pit - starting in 2018 or whenever
the water in the monitoring wells approaches the Critical Water
Level of 5,410'.
Back to top |
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