Document

Deep Sea Tailings Placement in Papua
New Guinea (PNG): Environmental
Impact Assessment, Monitoring and
Regulation
Tracy Shimmield
www.samsrsl.co.uk
Ramu Nickel mine in PNG
Simberi
Ramu
Lihir
Yandera
Woodlark
Misima
Suspended Particulate Material (SPM)
Ramu Nickel Mine
Western Transect
Stations 10,12,14
Outfall Transect
Stations 1,3,4,5,6,9
Eastern Transect
Stations 7,8,15
SPM Methodology
Depth of outfall 155 m
11m
50m
125m
140m
165m
186m
217m
SPM Concentration mg/l
SPM mg/l
SPM mg/l
0.0
0
0.5
1.0
1.5
2.0
Depth (m)
0.0
0
0.5
1.0
1.5
2.0
200
200
400
2.5
SPM mg/l
2.5
0.0
0
0.5
1.0
1.5
2.0
2.5
200
Western
Transect
Depth
of outfall
Stations 10,12,14
400
Outfall Transect
Stations 1,3,4,5,6,9
600
600
800
800
10 1050m
2 524m
14 283 m
600
Eastern
1 500m Transect
3 520m 7,8,15
Stations
4 252 m
5 1020m
6 250m
9 500m
1000
1000
WEST
400
800
7 250m
8 510m
15 1020m
1000
OUTFALL
EAST
SPM Iron Concentrations
0
Fe ( g/g)
1e+5 2e+5 3e+5 4e+5
0
Fe ( g/g)
1e+5 2e+5 3e+5 4e+5
0
0
0
0
200
200
200
400
400
400
600
600
600
800
800
800
Fe ( g/g)
2e+5
Depth (m)
Depth of outfall pipe
WEST
1000
OUTFALL
1000
10 1050m
12 524m
14 283m
EAST
1000
1 500m
3 520m
4 252m
5 1020m
6 250m
9 500m
7 250m
8 510m
15 1020m
4e+5
SPM Chromium Concentrations
Depth (m)
0
Cr (g/g)
100 200 300
400
0
Cr (g/g)
750 1500 2250 3000
0
0
0
0
200
200
200
400
400
400
600
600
600
800
800
800
WEST
1000
OUTFALL
1000
10 1050m
12 524m
14 283m
Cr (g/g)
100 200 300
EAST
1000
1 500m
3 520m
4 252m
5 1020m
6 250m
9 500m
7 250m
8 510m
15 1020m
400
SPM Copper Concentrations
0
Cu ( g/g)
500 1000 1500 2000
0
Cu ( g/g)
10000 20000 30000
0
0
0
200
200
200
400
400
400
600
600
600
800
800
800
1000
1000
1000
Depth (m)
0
10 1050m
12 524m
14 283m
1 500m
3 520m
4 252m
5 1020m
6 250m
9 500m
Cu ( g/g)
500 1000 1500 2000
7 250m
8 510m
15 1020m
Summary of SPM data
• Tailings material is detectable in the water
column at the stations closest to the outfall
(3, 4 and 6),
• Tailings material is detectable above the
depth of the pipe at stations 4 and 6,
• Results suggest an eastward transport of the
tailings material,
• There is another source of metals to the water
column at 50m at the outfall stations
Environment Regulatory Process
The environmental regulatory framework (Environment Act 2000) provides a
three-tier process for dealing with activities with potential for causing
environmental harm. Activities are classified as a Level 1, Level 2 or Level 3 activity.
Level 1 activities are activities with very low risk of causing environmental harm.
The environmental performance of these activities is guided by environmental
guidelines, codes of practices and notices. The Level 1 activities are also obliged to
comply with the Act
Level 2 activities have the potential to cause environmental harm, split into 2
categories A & B, level B activities have high potential for causing environmental
harm and are subject to the full environment permit assessment process.
Level 3 category is essentially those projects of national importance and have the
potential to cause serious environmental harm.
These activities are subjected to the environment impact assessment process.
DSTP is identified in the Environment (Prescribed Activities) Regulation as a Level
3 activity
Environment Regulatory Process
APPROACH
The General Guidelines for the use of DSTP should be used
by the Government Agencies and developers to determine
whether DSTP is a feasible option.
If the decision is to use DSTP as a waste management
option, then the general draft guidelines should be used by
the developer as a framework to design the Environmental
Baseline Study and the Environmental Plan’
Once the environmental baseline has been designed,
completed and the EIA approved by the relevant
government agency, then a set of Specific Guidelines
should be developed.
The Specific Guidelines should be written by the relevant
government agency and NOT the developer.
Specific Guidelines should be based on the results and
conclusions obtained from the environmental baseline
studies carried out by the developer.
General Guidelines for DSTP in PNG
Draft general guidelines have been developed.
For each mine site there will be a set of specific guidelines
General Guidelines for DSTP in PNG
In the context of international best practice, the
general guidelines for the use of DSTP in PNG
should consider an examination of;
1.
2.
3.
4.
Initial mine planning/development,
Mining operations, including monitoring,
Future mine closure plans and
Post mining monitoring.
The main aim of the guidelines should be to minimise
the impact on the marine environment while
achieving sustainable resource development.
The potential environmental risks to be
considered should include;
Assessment
1. of the toxicity of the tailings
2. of impact on seabed
3. of impact on the pelagic zone during the production
period
4. of impact on biodiversity during production period
Influence
5. on marine resources e.g. fisheries,
6. on vulnerable ecosystems,
7. Impact of technical failure e.g. pipeline fractures,
8. Potential redistribution of tailings
Initial Mine Development
Initial mine development consideration should include
•Preliminary site evaluation
•Environmental baseline survey
Appraisal of all practical waste management options
•DSTP
•On land storage, tailings ponds
•No tailings e.g. no mine
Appraisal should include latest scientific and
engineering knowledge and utilise all experience
gained from previous tailing systems
Critical Factors
• Properly designed outfall system e.g. durability and
length/depth of pipe
• A duplicate pipeline should be considered to allow mine
operations to continue during times of pipe inspection or
technical failure, where this is not implemented then an entire
pipe replacement unit must be kept on site for immediate use in
case of failure of the pipeline.
• The safety of the pipeline must be assessed, e.g. determine the
physical risks to the offshore pipeline, e.g. wave action, seismic
activity, trawling,
• Ensuring the correct density of the discharge to minimise
suspended particulate plumes and maximise placement on the
deep sea bed
Draft General Guidelines for DSTP in PNG
• Initial baseline survey crucial
– Physical oceanography; more than 1 years data
– Sediment geochemistry
– Benthic and Pelagic ecosystems
• Location and length of pipe
– Depth, minimum of 120m where mixed layer 80m or less, or
where mixed layer deeper than 120m, depth of mixed layer +
50% (this should be informed by oceanographic data)
– 2 pipe lines or alternatively 1 pipeline and entire replacement
pipeline stored on site
• Modelling and re-education of the models
• Continued monitoring over the life time of the mine and
beyond
• Continuous real time monitoring
• Independent scientific advisors to mine and relevant
competent authority
Site Specific
Guidelines for
DSTP for Lihir
and Ramu Mines
Funded by Government of
Papua New Guinea via the
Mining Sector Institutional
Strengthening Technical
Assistance Project 2,
funded by the
International
Development Agency.
Specific Guidelines
The Specific Guidelines are being developed as a management
tool for dealing with environmental applications where a mine
wishes to use Deep Sea Tailings Placement as the method of
tailings disposal.
The Specific Guidelines should be a dynamic and evolving
document that should be continually improved to meet new
demands.
The permitting process is important for the overall environmental
regulatory framework of the DSTP operation, with permits
detailing site-specific requirements including mitigation measures
identified during the EIA process.
Specific Guidelines
The main objectives of the guidelines are;
• to minimise the impact on the marine environment while achieving
sustainable resource development,
• inform and guide the developer/operator,
• assist government agencies to inform policy and regulation.
The development of Specific Guidelines for the use of DSTP at Ramu
and Lihir Mine Projects will;
• contribute to consensual, clear, environmentally defensible water
quality and mine tailing waste disposal management within PNG.
• form part of the Terms and Conditions of both the Environment
Permit issued by Department of Environment & Conservation (DEC)
and the Mining Lease issued by the MRA.
Specific Guidelines Considerations
The Specific Guidelines for each mine site considers;
• The ore being mined,
• The processes and chemicals used,
• The physical and chemical constituents of the tailings,
• The amount of tailings being discharged,
• The physical oceanography of the marine environment
into which the tailings will be discharged,
• The bathymetry of the marine environment into which
the tailings will be discharged,
Specific Guidelines Considerations
• The biodiversity of the marine environment into which the
tailings will be discharged,
• The land to ocean transfer that takes place, i.e. is there a
large fresh water and sediment input to the area,
• The fishing activity that takes place in the sea surrounding
the mine,
• The social, economic and cultural activities that may be
affected by the discharge,
• The integrity of the discharge pipe and mixing tank
including the consideration of the engineering required
together with emergency contingency plans.
Thank you for your attention
Gracias por su atencion
Level 3 activities are required to go through the environmental impact assessment
process and obtain an Approval In Principle before they can apply for an Environment
Permit
After the Minister has issued an Approval In Principle, the Proponent is then expected
to apply to the Director for an Environment Permit.