Pictures from left to right
What is a Mitigation Strategy
Environmental Impact Statement (“EIS”) Report
Solwara 1 Environmental Impacts
Solwara 1 Features
Nautilus Minerals Mitigation Strategies
Deep Sea Operational Mitigation Detail
What is a Mitigation Strategy?
- Rock sampling on the seafloor using an ROV
- Long-term temperature logger installed on the seafloor at Solwara 1
- “Suction sampler” used to sample animals from the seafloor
- Subsea scoop used to sample animals and rocks from the seafloor
A mitigation strategy is a series of measures put in place to minimize impacts to the environment.
Environmental Impact Statement ("EIS") Report
We have posted our Environmental Impact Statement, as submitted to the PNG government, on this website for public download. The Executive Summary can be downloaded in English or Tok Pisin. Click here to download these documents.
Solwara 1 Environmental Impacts
The main potential impacts to the environment during the production phase have been identified as:
- Material and habitat removal (seafloor);
- Plume generation/water quality disturbance from cutter head (deep sea);
- Plume generation/water quality disturbance from return water (seafloor, > 1300 m);
- Noise/Vibrations (on the seafloor and at the surface).
These impacts have been addressed in our mitigation strategies.
Impacts and mitigations (click on photo to enlarge)
Solwara 1 Features
There are several features related to the Solwara 1 Project that are worth noting:
1. The area to be mined is small (0.112 km2).
2. Vent-dwelling animals are already exposed to high metal concentrations from naturally-occurring local hydrothermal venting.
3. Within a few years, animals are expected to re-establish on the areas which have been excavated.
4. Plumes from a subsea volcano in the area cause naturally-occurring high sedimentation rates at Solwara 1 (proposed extraction site) and South Su (proposed reference site).
Extraction cannot remove or exhaust the natural hydrothermal energy source at Solwara 1, which will continue until the underlying geological energy source naturally dissipates. The active venting will continue, allowing re-establishment of vent-dependent and associated communities.
The time sequence for the recovery of fauna is not known precisely. It is expected that within a few years the major faunal elements will have re-established. This prediction is made based on observations taken during many years of research at various hydrothermal vent sites around the world. It is evident that animals living in such a highly mineralized area are tolerant to the naturally elevated levels of metals in ambient water and sediments.
Nautilus Minerals - Mitigation Strategies
Protecting the Deep Sea Environment - Operational Strategies
The operational mitigation strategies described below are aimed at reducing our impact on the seafloor environment. These strategies have been developed in consultation with an international team of marine science experts. The objectives are the protection of biodiversity and maintenance of nearby communities of animals to enhance the rate of post-production recovery. The proposed mitigation strategies are:
1. Unmined reference area at South Su – to provide a “parent stock” of animals and to allow studies of natural environmental variation away from mining;
2. Temporary refuge areas within Solwara 1 –will help excavated areas recover with respect to biology;
3. Enhance recolonization - some animals will be relocated from non-excavated areas within Solwara 1 to areas where excavation is complete within Solwara 1; and
4. Artificial substrates to provide re-population habitat - increases chances of rehabilitation.
Protecting the Mid-Ocean to Surface Environment - Operational Strategies
The avoidance of impacts on coral reefs, fish and large marine animals such as whales, dolphins and turtles from discharge of water and entrained sediments from the dewatering process on the Production Support Vessel ("PSV") will be achieved by:
1. Discharging at depths between 25 to 50 metres above the seafloor to confine all impacts to the bottom zones from where the water/sediment originated.
2. Filtering the water prior to release, which is expected to significantly reduce the quantities of sediment lost in the dewater discharge.
3. Limiting the exposure time of the return water to surface temperatures and oxygenation, thereby reducing potential for geochemical changes. The pipes used to transport the return water to the seafloor will allow for cooling of the return water.
The result of these strategies is that the Solwara 1 Project will cause no harm to fisheries, coral reefs, whales, turtles or other pelagic animals.
Deep Sea Operational Mitigation Plans - Detail
1. Reference Area at South Su
South Su is proposed to remain as a reference area about 2 kilometres up current from Solwara 1 until the completion of production operations and confirmation that the rehabilitation techniques are effective at Solwara 1. It is expected to provide a source of recruitment to excavated areas and provide a reference location to monitor natural variations in vent activity and communities over time. Biological comparisons of the two areas have shown that the samples taken from the active sites at both Solwara 1 and South Su share the same biomass-dominant species and generally similar indices of diversity and community structures. Where there are significant differences, South Su generally has higher abundances of secondary species and higher dominance of some groups. Some recruitment may also come from North Su (active subsea volcano), where extraction is not currently planned. However, because of the continuous active conditions and sediment-occluded visibility at North Su at the times of surveys, it has not been possible to characterize its vent communities to the same extent as at Solwara 1 and South Su.
2. Temporary Refuge Areas within Solwara 1
Not all of the resource can be extracted simultaneously. The areas which will be excavated last will function as undisturbed sources of parent fauna and supply of larvae within Solwara 1 for the greatest amount of time.
The expectation for these areas is that recovery will be sufficiently well-progressed to meet specified criteria. Progress against criteria will be examined through monitoring to determine if the major community elements (i.e., the three biomass-dominant species) have re-established at active chimneys in the earliest worked-out area. Production at the refuge areas will not commence until these recovery criteria have been met.
3. Transplant of Animals
The loss of animals in the path of the Seafloor Mining Tool ("SMT") can be minimized. It is proposed that the ROV be used to remove large clumps of rock substrate with its biology intact and relocate them to appropriate areas that have been excavated. These clumps will be targeted to maximize the biomass-dominant species and any other associated attached or sessile fauna. Monitoring will be undertaken to confirm the success of this strategy.
4. Artificial Substrate
Hard substrate animals (e.g. coral) and their associated fauna in mainly inactive areas away from the vent ecosystems are expected to recover more slowly (compared with animals located in active vent areas). In order to enhance recovery, hard settlement surfaces may be established in appropriate areas. Using an ROV, animals will also be removed from the path of operations and repositioned in structures such as crates, where they might reform attached colonies. The survival and growth of such transplants will be monitored, with continued relocation if successful.
Photos: Nautilus Minerals Inc.