CYANIDE
RELEASES AND OTHER WATER QUALITY IMPACTS AT
MONTANA GOLD MINES - CASE STUDIES
[SOURCE:
"Nothing
New Here: A Technical Evaluation of Initiative
147" (470K
PDF), Jim Kuipers, P.E., September 2004.]
|
| DATE |
MINE |
OCCURRENCE |
|
1998 |
Golden
Sunlight |
Cyanide
spill due to leak in the liner system. Cyanide
detected in groundwater wells at levels between
30 and 39 ppm (150 times state human health
standards). The mining company did not notify
the agency of the spill until a month and a
half after it occurred. The company did not
have pump-back wells on site to address the
spill. |
Basin
Creek |
Nearby
stream (West Clear Creek) contaminated by improper
"land application". Cyanide measured
at levels that exceed state water quality standards. |
Zortman/Landusky |
Pegasus filed
for bankruptcy. The MT DEQ has determined that
the reclamation bond is inadequate, and has
asked the bankruptcy court to increase the bond
from $30 million to $38.5 million. |
Kendall |
Issued
a notice of violation for failure to comply
with effluent limits for thallium, cyanide,
arsenic and manganese. |
Kendall |
DEQ issued
a $330,000 penalty for extended water quality
violations, including 9 exceedances for nitrates,
50 exceedances for thallium, 16 exceedances
for selenium, 6 exceedances for antimony, 13
exceedances for manganese, 5 exceedances for
arsenic, and 6 exceedances for cyanide. |
Kendall |
DEQ
found that Canyon Resources had implemented
much of the capping requirements on the waste
rock pile without approval from the agency.
As a result, the company used materials containing
elevated levels of thallium and arsenic to construct
the cap. Subsequent testing of seepage issuing
from the cap has indicated the presence of elevated
thallium. |
1997 |
Basin
Creek |
Nearby stream
(West Clear Creek) contaminated by improper
"land application". Cyanide measured
at levels that exceed state water quality standards. |
Zortman/Landusky |
Water
quality violations culminated against the company. |
|
1996 |
Beal
Mountain |
1,200 - 2,500
gallons of cyanide solution were spilled at
the processing plant. |
| Zortman/Landusky |
The
upper reaches of Carter Draw, Alder spur and
Ruby Gulch, have elevated concentrations of
sulfate, TDS, metals, nitrates and occasional
detections of cyanide. This water fails to meet
aquatic life standards and human health criteria,
and is currently being captured and treated
before being discharged to Ruby Gulch. The lower
reaches of Alder Gulch and Ruby Gulch show a
record of being significantly impacted by acid
rock drainage or process chemicals. |
|
1995 |
Kendall |
Cyanide spill
occurred due to torn pond liner. |
| Kendall |
DEQ
issued a notice of violation for numerous water
quality violations. Their report stated that
the sources of the discharges were reclaimed
and unreclaimed waste rock dumps and heap leaches,
open pits and other mine related facilities. |
| Golden
Sunlight |
Possible small
leak in east reclaim basin. Low level cyanide
measured at three groundwater sample sites. |
|
1994 |
Golden
Sunlight |
Cyanide
solution leaked from spare tailing line. Forty
pounds of cyanide were contained in the discharge.
A notice of noncompliance was issued against
the company for failure to notify the state
of the spill and conduct immediate clean-up. |
| Golden
Sunlight |
48.3 tons of
tailings were spilled due to a leak in the spare
tailing line. State agencies were not notified
until many months after the event. Anotice of
noncompliance was issued against the company
for failure to notify the state of the spill
and conduct required clean-up procedures. |
| Kendall |
Cyanide
leaked from holding pond due to liner tear. |
|
1993 |
Zortman/Landusky |
The State issued
notice of noncompliance for cyanide contamination
due to improperly installed liner and underliner
failure. Inspection reports indicate that between
5,000 and 10,000 gallons of cyanide solution
were released and entered the fractured bedrock
aquifer. Groundwater monitoring wells revealed
cyanide at levels exceeding human health standards. |
| Zortman/Landusky |
A
notice of noncompliance was also issued for
illegally disposing of sulfide waste. |
| Basin
Creek |
Leak was discovered
at the toe of the process pond dike. An estimated
130,000 gallons of solution may have been discharged.
The company was forced to install a lined sump
and pumpback system to collect the released
fluid. |
| Zortman/Landusky |
A
U.S. EPA inspection tour noted the following
violations: leach pad underdrains discharging
to Montana Gulch; Gold Bug adit discharging
to Montana Gulch; Mill Gulch Waste Dump discharging
to Rock Creek; and seepage from the Alder Gulch
waste dump discharging to Carter Gulch. Analysis
of Gold Bug adit water contained concentrations
of arsenic, cadmium, chromium, copper, iron,
nickel and zinc exceeding surface water quality
standards. |
| Zortman/Landusky |
A DSL report
concluded that there was acid mine drainage
in Ruby Gulch and Alder Gulch, two drainages
flowing out of the mine site. |
| Zortman/Landusky |
Despite
a pump-back system, seepage from Alder Gulch
Waste Dump flows into surface water in Carter
Gulch and Alder Gulch. The State said the wastewater
contained 840 times the amount of manganese
permitted by state regulation and nearly 25
times the standard for TDS. |
| Zortman/Landusky |
The BLM issued
a notice of noncompliance against Zortman/Landusky
for improperly constructing 1,000 feet of road
in the Alder Gulch drainage. Zortman placed
fill in a stream channel, on side slopes and
in and above the stream. |
| Zortman/Landusky |
An
EIS 1996 concluded that the upper reaches of
Carter Draw, Alder spur and Ruby Gulch have
elevated concentrations of sulfate, TDS, metal
nitrates and occasional detections of cyanide.
The water failed to meet aquatic life standards
and human health criteria, and is currently
being captured and treated before discharge
to Ruby Gulch. The lower reaches of Alder Gulch
and Ruby Gulch show a record of being significantly
impacted by acid mine drainage or process chemicals. |
| Golden
Sunlight |
Cyanide solution
from tailings impoundment leached into groundwater
and surfaced as seeps which flowed into an intermittent
drainage below. Cyanide concentrations ranging
up to 45 ppm total cyanide (204 times human
health standards). |
| Golden
Sunlight |
In
August, a 7 gpm seep was discovered in a drainage
area below the tailings impoundment. Cyanide
levels in the seep were measured at 0.6 ppm
(3 times human health standards). Another seep
was found further down the drainage. |
| Basin
Creek |
Leak in the
liner at the toe of the process pond caused
up to 130,000 gallons of solution to be released
over 3 days. Monitoring well revealed 52.3 ppm
cyanide. |
| Beal
Mountain |
Water
quality standards may have been exceeded for
nitrate, sulfate, TDS, manganese, selenium and
zinc in the German Gulch drainage and groundwater
in the vicinity of the mining operation. The
U.S. EPA issued a notice of violation for unlawful
discharge at the mine. |
|
1992 |
Beal
Mountain |
Cyanide seeped
through holes in the pond liner system and contaminated
natural springs. Springs were also contaminated
with sulfate and nitrate levels exceeding state
water quality standards. Cyanide continued to
be detected in the spring for 6 months. Beal
Mountain's 1988, 1989 and 1991 monitoring reports
were not submitted until 1992. A notice of noncompliance
was issued against the company for failing to
report the cyanide leak. The DSL also notified
Beal Mountain that sulfate levels at a spring
monitoring site had increased by a factor of
four. |
| Kendall
|
2,400
- 3,000 gallons of solution spilled due to a
ruptured pipe. Cyanide solution left the mine
permit boundary. |
| Golden
Sunlight |
Groundwater
monitoring wells revealed cyanide levels far
exceeding human health standards of 0.2 ppm.
The east side pumpback wells contained 250 -
300 ppm cyanide. The south pumpback wells contained
100 ppm cyanide. |
| Zortman/Landusky |
A
cyanide leak occurred due to a pipeline failure,
causing groundwater contamination. Maximum contaminant
levels for arsenic, cadmium, chromium and copper
were exceeded in Ruby Gulch. Significant deterioration
of water quality also occurred in Mill Gulch. |
| Zortman/Landusky |
At
the Ruby Gulch cyanide heap leach pad, "a
weeping wall of heavily contaminated seeps appeared
and continues to present." Despite a seepage
collection system, the surface water flowing
through Ruby Gulch in 1992 showed levels of
arsenic at 0.126 mg/L, two and one-half times
the state standard for arsenic (0.05 mg/L). |
| Zortman/Landusky |
The
Sullivan Pad complex has massive seeps from
its base to surface and groundwater and have
been unable to recover all of this seepage with
its seepage collection system and pump-back
well. Water in Sullivan Creek contained 14,700
mg/L of dissolved solids (State standard is
250 mg/L), 110 mg/L of manganese (State allows
only 0.05 mg/L), 536 mg/L of iron (State permits
0.3 mg/L). |
1991 |
Kendall |
Emergency land
application of process water killed surrounding
trees. |
| Kendall |
Cyanide
leaked through tear in the liner system caused
by improper bulldozer operation. |
| Zortman/Landusky |
An agency memo
states that "cyanide is widely distributed
in groundwater below the leach pad." Nine
wells showed cyanide in 1991. |
| Zortman/Landusky |
Surface
water monitoring below the heap leach pad revealed
water pH levels of 4 (acidic) and sulfate levels
of 1,400 mg/l (revealing acid mine drainage).
pH levels of 2.6 and sulfate levels of up to
3,500 mg/l were measured in Ruby Gulch. pH levels
of 3.5 were measured in Rock Creek. |
| Basin
Creek |
A monitoring
and pumpback well below Leach Pad 1 indicated
cyanide contamination at levels that exceed
state water quality standards. Cyanide levels
continued to exceed standards for three month.
25,820 gallons of cyanide solution were pumped
back. |
| Golden
Sunlight |
60
pounds of cyanide spilled due to tailings line
leak causing soil contamination. |
|
1989 |
Basin
Creek |
Cyanide solution
ran from process station down road and off into
woods. |
| Basin
Creek |
DSL
issued a notice of noncompliance against Basin
Creek for violating its operating permit by
allowing cyanide laden material to be distributed
off a lined and bermed area. The company was
fined $2,860 for 11 days of violation. |
| Beal
Mountain |
In May, Cyanide
was detected in three ground water monitoring
wells. |
| Beal
Mountain |
In
June and July, total cyanide concentrations
of 0.02 ppm and 0.012 ppm were reported in spring
5. |
| Beal
Mountain |
In July, spring
3 contained 0.045 ppm total cyanide; spring
9 contained 0.039 ppm total cyanide; German
Gulch had 0.028 ppm total cyanide. |
| Golden
Sunlight |
Pipeline
blockage caused acid mine drainage to discharge
onto the ground. |
| Zortman/Landusky |
60,000 cubic
feet of leach pad slipped. |
1988 |
Golden
Sunlight |
A
pipeline leak occurred sometime between March
31 and April 5 before it was discovered by the
company. Approximately 15,000 gallons of mine
waste flowed from the emergency spillway of
the secondary dam down the drainage about 100
yards. |
| Zortman/Landusky |
High rains
were followed by cyanide concentrations exceeding
human health standards at a surface water station
in Ruby Gulch. BLM reports in 1990 show that
cyanide contamination in Ruby Gulch continued
for a two year period. |
| Zortman/Landusky |
Cyanide
was detected in groundwater monitoring wells.
The cyanide spill occurred due to a tear in
the liner system. |
1987 |
Zortman/Landusky |
Cyanide spill
caused by hole in liner system: groundwater
contaminated. |
| Zortman/Landusky |
A
Ruby Gulch surface monitoring site yielded trace
cyanide caused by two dripping process lines.
In 1988 cyanide levels increased to 0.2 ppm
(ten times state surface water quality standards). |
| Zortman/Landusky |
Cyanide spill
occurred due to dripping process lines: surface
water contaminated. |
| Basin
Creek |
Cyanide
spill occurred because a solution valve was
left open. Groundwater contamination resulted. |
| Golden
Sunlight |
A cyanide slurry
spill occurred. Estimated that the spill included
60 pounds of cyanide contained in a combination
of 40 tons of solids and 40 tons of solution. |
1986 |
Zortman/Landusky |
A storm caused
Pegasus to spray 20 million gallons of process
water on a hillside, resulting in tree kills.
This event involved a nearly catastrophic failure
of the pond system. |
| Golden
Sunlight |
A pipe fitting
split and discharged approximately 2,000 gallons
of cyanide solution. |
1985 |
Zortman/Landusky |
Storm
event caused mining company to land apply process
water on 17 acres of land. Tree kills resulted. |
| Golden
Sunlight |
19 million
gallons of cyanide solution leaked when a tailings
impoundment failed. Resulting groundwater contamination
affected the Jefferson River alluvium. Four
domestic wells and a well at the veterinary
clinic were contaminated. Placer Dome was sued
by neighboring landowners. The company eventually
bought out the landowners. |
1983 |
Zortman/Landusky |
1,000
- 1,200 gallons of cyanide solution spilled
due to a ruptured pipe. |
| Zortman/Landusky |
Leach pad suffered
mass movement causing the liner system to be
ripped. Cyanide was detected below the dike
in Ruby Gulch. One month later a 50 x 100 foot
containment pond was built to capture further
leakage. |
| Zortman/Landusky |
Approximately
1,000 gallons of cyanide solution spilled into
Alder Gulch due to pipeline failure. |
| Zortman/Landusky |
200 gallons
of cyanide solution spilled from the leach pad.
50 gallons puddled on the ground. |
| Zortman/Landusky |
A
leak in the pond liner was discovered after
cyanide contamination was identified in the
nearest monitoring well. |
1982 |
Zortman/Landusky |
Ruptured pipe
caused 1,200 gallons of cyanide to be spilled. |
| Zortman/Landusky |
50,000
gallons spilled into Alder Gulch contaminating
Zortman's community water supply. Pegasus was
required to replace the drinking water source.
The State issued a $15,000 fine against the
company. |
| Zortman/Landusky |
75 gallons
of cyanide solution spilled. |
| Zortman/Landusky |
300
gallons of cyanide solution was spilled when
the top of a leach pad froze and cyanide flowed
over the top onto the ground. |
| Zortman/Landusky |
4 pounds of
cyanide spilled, contaminating groundwater. |
| Zortman/Landusky |
780
gallon leak in the gold recovery system. Soil
contamination resulted. |
| Zortman/Landusky |
Bighorn sheep
found dead at cyanide ponds. |