Land Treatment of Mine Water
Presented by:
Andre Sobolewski,
Microbial Technologies
Proposed Treatment
•Metals are predicted to be at very
low concentrations, so focus is on
ammonia
•Land treatment is proposed
•Propose to spray mine water onto
land (spray irrigation), where plants
and soil microbes utilize ammonia
–This will effectively fertilize the land
Spray Irrigation – What is it?
•Spray guns are spaced apart to apply
water evenly across treatment area (can
be moved around)
•Water is pumped from PKCA through
network of ‘spray guns’
•Treatment occurs as water travels
through soil
•Both ammonia and metals will be
removed
Spray Irrigation
Spray Irrigation - Characteristics
•Advantages:
–Simple (few parts needed, easy to assemble and
easy to get parts)
–Flexible (easy to start and can be moved around)
–Used worldwide (extensive experience under many
conditions)
–Inexpensive
•Disadvantages:
–Not yet applied in Arctic
Spray Irrigation Area
• Proposed spray site located between PKCA
and Lake C3
• Area is large enough
– Calculations show that 5 hectares would be
required, there are over 15 hectares available
• Gently sloping (1-3% slope)
• High proportion (>70%) of continuous
vegetative cover, not boulder fields
• Organic-rich soil
• Field trials conducted in 2001 show that the
land is suitable for spray irrigation
Potential Impacts - Chloride
• Concern was expressed about effects of
salts - specifically chloride - on plant health
• Tests were conducted during study on site
–Chloride shown to be toxic at 1,000 mg/L
–Chloride in PKCA water is expected to be
present at a lower concentration
–Chloride will not accumulate in soil
• No environmental impact is expected
Evaluation of potential impacts
• Chloride – not present at toxic levels
• Ammonia – Stimulates plant growth
• Metals in soil – will be monitored
• Salts in soil – salt concentrations will
decrease during the project
• Permafrost – will be monitored
Monitoring program
• Monitoring program will be developed to ensure that
good quality water is discharged into Lake C3
• Metals will be monitored in soil
• Active layer will be monitored
• Treatment area will be moved or expanded if:
• Ammonia concentrations are too high
• Metals start to accumulate excessively in soils
• Permafrost begins to deteriorate
Summary
•Water treatment may be required if
ammonia and metals levels are elevated
•PKCA discharge will be monitored
•Spray irrigation will be used to remove
ammonia and metals from discharge, if
necessary
•A monitoring program is proposed to
mitigate potential risks