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Environmental and social responsibility

Prony Resources is committed to conducting its operations by reducing and controlling its impact on the environment and on the exceptional biodiversity of the Great South of Caledonia.
This commitment is based on five guidelines:
  • Control environmental risks
  • Limit the ecological footprint and fight against climate change
  • Guarantee the compliance of activities and facilities
  • Preserve biodiversity
  • Dialogue with interested parties

The great south region, a hotspot of biodiversity

The mining and industrial facility is located in the heart of an exceptional natural environment and bordered by several provincial reserves, a RAMSAR zone as well as a UNESCO World Heritage Site. The company has been an important partner in classification projects, bringing its expertise on the region's ecosystems. In addition, the state of health of the environment (fauna and flora) is monitored at these reserves and forest areas of heritage interest.

Our approach to preserving biodiversity begins already in the design of projects and installations, where we consider the issues by systematically carrying out an environmental impact study and applying the principle of “Avoid, reduce, compensate”.

An ambitious and innovative biodiversity conservation plan

This plan, which has been in operation for the last 20 years, includes avoidance, mitigation and compensation measures established in collaboration with the various scientific communities. Fueled by inventories of flora and fauna targeting the heritage sites, innovative conservation programs for rare and threatened species have made it possible to sow more than 11,000 plants.
Member of the IUCN (International Union for Conservation of Nature), Prony Resources thus contributes to the regular updating of the red list of rare and threatened species.

An industrial nursery

Largest infrastructure in New Caledonia for the production of local and / or endemic plants, the nursery of Prony Resources produces more than 300,000 plants per year. These are used for the restoration of 30 hectares per year of degraded land, or nearly 300 hectares since 2002. Teams of botanical experts have been working since 2007 to identify, study, harvest and reproduce these local and / or endemic plants. In addition, 6 satellite nurseries have been created in neighboring tribes in order to contribute to this sustainable effort and to promote the economic development of the region.

Extensive environmental monitoring

Prony Resources ensures the management and environmental monitoring of all its mining and

industrial activities through a vast monitoring network. This comprises 580 stations, which together collect 5,620 sampling cycles per year on surface water, groundwater, water quality, air and the marine environment. The environmental aspects and associated risks are systematically evaluated periodically and in the case of any change of activity or installation in an effort to avoid or reduce significant environmental impact.

The results are communicated to the supervisory authorities and stakeholders, including the general public, by an independent body (Observatoire de l'Environnement). Finally, the communities are involved in this monitoring through a customary environmental council.

A long-term vision to limit our ecological footprint

By seeking energy sobriety and efficiency, Prony Resources is embarking on a process of transition to renewable energies with the ambitious goal of reducing its carbon footprint by 50% within 10 years and achieve carbon neutrality by 2040.

A shared vision of social and economic development

A unique and recognized commitment to communities

Relations between the Grand Sud plant and the community within which it operates are based on a unique and innovative agreement called the Great South Sustainable Development Pact. The pact aims to involve the inhabitants in the protection of the areas’ environment and socio-cultural and microeconomic development through the creation of 3 structures of co-governance. This approach has been recognized by the United Nations.

3 governance structures

  • The Customary Environment Advisory Council
    Its mission is to ensure the participation of communities environmental monitoring of the Great South. Local technicians monitor the surveillance plan and report the results directly to the communities who can make recommendations to the company.

  • Corporate Foundation
    The first corporate foundation created in New Caledonia promotes socio-cultural and educational projects proposed by local populations. It also provides support for local economic activities, school grants, customary events, the construction of tribal infrastructure, the promotion of the local language, and fishing.

  • Reforestation Association
    It develops revegetation programs for degraded areas - unrelated to mining - proposed by local communities, by economically-efficient forestry and ecological projects. It is also leading a program to eradicate invasive flora species on customary lands.

  • A sustainable economic partnership with local entrepreneurs
    The company is committed to ensuring economic benefits for local entrepreneurs.

    • Creation of an economic structure bringing together 80 entrepreneurs from the region and enabling subcontracting of industrial and mining activities.
    • Local purchasing and partnerships
    • Local employment (+ 99% local contracts)
    • 75 subcontractors from local communities, i.e. nearly 600 jobs
    • 35 M USD of local contracts per year

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Responsible tailing management

The hydro-metallurgical process for the extraction of nickel and cobalt requires the production of neutralized wet residue, mainly composed of iron oxides initially present in the deposit and gypsum. They are stored in a tailings site covered with a geomembrane and closed by a class A dam, monitored by 230 instruments and regular internal inspections as well as various external and independent controls. The results to date indicate that it behaves normally and does not exhibit any failure.
The tailings site is currently 60% full and will reach its maximum authorized capacity of 45 million m3 at the end of 2023. The implementation of the Lucy project will ensure continued production by combining the dam with sustainable storage of dried-up tailings.


TOP 10 questions that everyone asks about the KO2 dam

What is the KO2 dam?

The industrial process used by PRNC generates residue. This residue, once treated and neutralized, must be stored. The residue park is a large basin with the purpose of storing this residue. This basin is enclosed by the dam called KO2.

How else can one store the residue?

Different ways of managing mine tailings exist: disposal at sea, storage in a tailings pond, storage in the form of solid / dry tailings, etc. The most conventional and widespread storage is storage in a tailings pond. With technological developments and increasingly stringent directives, we are seeing more instances of storing residue in solid / dried form. Prony Resources has foreseen this transition by launching the Lucy project.

What is in the basin?

The basin contains neutralized wet residue. It is deposited via a pipe into the basin which is completely covered with a membrane in order to minimize infiltration.

Before being sent to the basin, the residue is treated at the plant by mixing it with lime. The lime neutralizes the sulfuric acid contained in the residue and thus eliminates all traces of acidity in it. The residue has a neutral pH: the residue contained in the KO2 residue pond therefore does not contain acid, and is mainly composed of iron, aluminum, and gypsum. The supernatant liquid part, which then only contains a few dissolved metals (magnesium, calcium, sodium, manganese), is returned to the plant for treatment before being discharged into the sea.

Is the dam solid?

It is a large basin and therefore a large dam. We understand that the size of this element may cause concern, but this structure is reliable, highly supervised, in accordance with the law and subject to numerous independent controls.

The KO2 dam has been built and is monitored according to international best practices. The PRNC teams as well as external researchers, with extensive expertise, carry out continuous monitoring of the structure. The dam is also checked on a regular basis by recognized international experts.

A reliable structure

The design of the dam as well as the technical requirements for its construction received a favorable opinion from the Permanent Technical Committee for Dams and Hydraulic Works (CTPBOH) on two occasions, in 2005 and equally in 2008. For the record, the CTPBOH is the uppermost important French authority within this matter.

A supervised structure

  • 230 measuring instruments enable the measurement of all the structure’s parameters.
  • Various inspections are carried out on a daily, weekly and monthly basis.
  • Technical inspections are organized regularly and entrusted to the best international experts, including:
    • The independent Tailings Review Board, a technical committee consisting of 3 independent international experts who carry out an annual appraisal on the KO2 tailings site and related projects such as the Lucy project;
    • An accredited French research team in charge of the annual in-depth technical visit;
    • International researchers in charge of carrying out an annual inspection of the dam (Dam Safety Inspection);
  • Many specialized research teams are also in charge of carrying out various studies.
Can the dam withstand a cyclone?

Yes of course, the meteorological risk has been considered, in particular extremely rainy and windy weather. This is an imperative condition to obtain an official authorization to operate.

15 major events have been recorded over the past 18 years. Suffice to say that the dam has already demonstrated its resistance.

The most intense event is also very recent and dates to February 29, 2020. 386 mm of rain fell within 6 hours, equivalent to the amount of rain that we would normally experience during a full month in February! This episode occurs on average every 400 years and the dam showed absolutely no signs of disorder.

Can the dam resist earthquakes?

Yes, the dam was designed, built and approved with consideration of the seismic risk in the area. The stability of a structure under seismic stress is essentially evaluated based on three factors: the earthquake’s frequency, its intensity and the acceleration of the soil generated.

The safety margin will be further improved by the construction of a stopper. This is not due to a risk of failure, it is to follow evolution in knowledge and guidelines. This stopper will withstand earthquakes of exceptional magnitude.

The dam must be reinforced, does this mean that it is weakened?

The reports received from our network of instruments and international external experts indicate that the dam is functioning normally and does not present any faults. The dam is therefore not weakened. A toe stopper (downstream of the dam) should be installed, not because of any poor performance, but because of an evolution in international design guidelines (ANCOLD in particular).

Studies to design this toe stopper are in progress. Preparatory work in the area (earthworks and water management) should begin in 2021 to allow construction of the toe stop. The construction of this toe stop will begin as soon as the preparation work is finalized. This work is integrated into the Lucy project.

What is the lifespan of the dam? What will happen when there is no more industrial activity? Is it a time bomb?

The dam passes through three phases during its lifespan:

  • Construction,
  • operation,
  • and closing.

Once the operation is complete and closed, the residue park will continue to be physically present, but it will be inactive. Its closing is followed by a rehabilitation and revegetation phase. This type of closure plan is included in the Lucy project.

The Brumadinho dam, which was controlled by Vale, collapsed. Why should we trust you?

The commonalities between the Brumadinho dam and KO2 are the shareholder’s nationality and the fact that it is a dam. There are many fundamental differences between the two dams, including the method of construction:

  • Brumadinho was erected as it was filled, by successive extensions, each resting on the previous deposited residue. It had no internal drainage system or sealed core. This is a so-called bottom-up construction.
  • KO2 was built using a top-down method in 3 phases, which rely entirely on the foundation soils and not on the tailings. The dam has an internal drainage system and a sealed core, these two organs are intended to prevent the installation of a sheet of water in the body of the dam.

It's understandable that the general public compares one dam with another dam, but comparing Brumadinho and KO2 is a bit like comparing two cars because they have wheels and a steering wheel.

So why are there so many concerns and doubts expressed by certain local actors?

All the experts who inspect our dam ask us the same question. We have probably not explained enough how the dam works and how it is monitored.

The dam is stable, increased surveillance is carried out, studies are constantly carried out, and experts confirm that the dam is well managed.