INNOVATION AND SAFETY IN TAILING DAMS

From initial design to final closure, safety and operating excellence is fundamentally important in building and operating Antofagasta Minerals’ tailing dams and waste dumps.

WHY IS WASTE MANAGEMENT IMPORTANT?

All industrial processes generate waste, which under Chilean law must be stored and disposed of safely.

The mining industry has its own specific types of waste which, because of their volume and characteristics, are stored in sterile materials dumps, ordinary waste dumps and tailing storage areas. This situation is very unlikely to change in the future, so the waste requires safe, sustainable long-term storage technology.

Because the tailing storage areas are very large and built to last for a very long time, they must be able to withstand extreme climatic conditions and coexist with local communities and businesses.

Context
In 2016, the ICMM defined the international mining industry’s position on tailings storage. This is summarised in a document “Position Statement on Preventing Catastrophic Failure of Tailings Storage Facilities”, which lays down recommended good practice for mining operations.

Chile has the third largest number of tailings facilities in the world, with 119 active and over 600 inactive sites. These are strictly regulated from initial design to dam closure. Regulatory responsibility lies with Sernageomin, in conjunction with technical bodies in each region where there are mining operations.

Recent international disasters affecting tailings storage have caused great concern in the mining industry and in local communities, which are aware that the facilities must be stable and must not affect the use of land and water.

HOW DO WE MANAGE WASTE?

Our operations generate sterile material, spent ore and tailings. Los Pelambres, Centinela Concentrates and Zaldívar generate tailings, while Centinela Cathodes, Antucoya, and Zaldívar produce spent ore. All of the mines generate sterile material, which is placed in storage.

Given the social context in which Los Pelambres currently operates, managing waste is a highly complex task. It therefore works closely with various key stakeholders on a Dam Programme, which is being piloted at the Mauro tailings dam.

Antofagasta Minerals is a member of the tailings working group established by Consejo Minero, which has four priorities: facilitating the implementation of the ICMM’s position statement in Chile, producing an emergency manual for tailings dams, developing an online tailings storage monitoring programme and keeping the Consejo Minero’s tailings website up to date. We are also a member of the ICMM’s tailings working group, which in 2017 issued recommendations for improved management of this infrastructure.

Organisation and reporting
Responsibility for waste management lies with the General Managers of each operation who report on this matter to the Board, while monitoring and disclosure are the responsibility of the Corporate Environment department. We have continued to improve our community notification and alert systems with the community, particularly at the Mauro dam, since 2015.

Cerro Amarillo sterile rock dump
Los Pelambres began operating in 1999 with permits granted by the relevant Chilean technical and environmental agencies. In 2004, the authorisation was granted to operate Cerro Amarillo, a dump for the inert rock that was removed to access the ore at Los Pelambres. As for all dumps this authorisation included an environmental closure plan approved by the Chilean mining technical organisations. In 2014, this dump become an international issue following a change in 2012 of the location of the border between Chile and Argentina, which resulted in part of the Cerro Amarillo dump being in Argentina on property owned by Glencore. From the beginning, Los Pelambres has been willing to seek a joint solution and in 2017, we reached an agreement for the removal of the dump from Argentine territory within a certain period.

Waste and recycling
Our processes produce hazardous industrial waste such as used oil and batteries, and non-hazardous items such as mud and timber. We store these in accordance with legal requirements. We aim to recycle waste wherever possible and make every effort to avoid disposing of it. Where we do this, we always use authorised sites. In addition to the existing laws, a new Extended Product Liability Act came into force in 2017. This aims to reduce waste and promote recycling by extending liability to the producer. Our mining operations already measure the recycling of non-mining waste and in 2017, 66 percent of the waste we generated was recycled. The figure was 82 percent for Los Pelambres and 56 percent for Centinela.