About the Global Tailings Portal

The Global Tailings Portal, launched in January 2020, is a free, searchable database with detailed information on more than 1,800 mine tailings dams around the world. It enables users to sort data about tailings dams by location, company, dam type, height, volume, and risk, among other factors. The data was submitted by more than 100 of the world’s largest mining companies, in response to requests from institutional investors. Previously, very little information about mine tailings dams was publicly available. The portal is designed to be used by governments, scientists, the finance community, the mining industry, media, and civil society.

The portal was built and is hosted by GRID-Arendal in collaboration with the Investor Mining and Tailings Safety Initiative, which is co-Chaired by the Church of England Pensions Board and the Swedish National Pension Funds' Council on Ethics, with support from the UN Environment Programme.

This current “beta” version of the portal (24th January 2020), is still undergoing testing and, development and verification. We welcome feedback, and note that the portal provides links to the underlying public disclosures that companies have made.

More detailed information on the methodology applied to translate data from company disclosures into the portal database is available in our Methodology section, and further details of our quality assurance processes are available below.

In due course we intend to make the database available as a downloadable Excel and CSV file. Currently, this data is available on request from GRID-Arendal (see below).

The origins of the Global Tailings Portal

On 25 January 2019, a mine tailings dam in Brumadinho, Brazil, collapsed, unleashing a torrent of mine waste that killed at least 259 people. It followed a previous tailings dam collapse in Mariana, Brazil, in 2015 that killed 19 people, and a longer history of other dam failures.

The 2019 disaster galvanized a group of major institutional investors to address the issue of mining and tailings safety and demand information from mining companies on where and how they store their waste. Led by the Church of England Pensions Board and the Swedish National Pension Funds' Council on Ethics, the group established the Investor Mining and Tailings Safety Initiative. The initiative is now supported by funds with more than US$13 trillion in assets under management.

In 2019, the Investor Mining and Tailings Safety Initiative asked 727 publicly listed mining companies for detailed disclosures on their tailings storage facilities (TSFs). As of December 2019, 332 had responded – of these, approximately 100 companies have tailings storage facilities and provided information. The data they submitted has been incorporated into the Global Tailings Portal.

The Methodology Section [here] provides information about how these disclosures have been incorporated into the Tailings Portal. The portal provides access to both the raw data disclosures and the database of these disclosures that GRID-Arendal has developed.

The development of the database has included a quality assurance protocol, where companies who submitted data have been contacted to verify their information. The database now includes a number of amendments, and we remain open to receiving comments and feedback from disclosing companies. Please see the ‘How to get in touch’ section below.

As of January 2020, approximately 60 companies have signed off on the data presented in the portal. The remaining companies are in the process of verifying their information. We recognise that the disclosures on which our data set is based may change over time, and companies are invited to contact us (and those who initiated the disclosure request) in order to help update our records. The Global Tailings Portal is convening an Advisory Group to guide the development of data processes and updates, in order to facilitate the good functioning of the portal as a tool for all stakeholders.

The Disclosure Questions

  • Q1. "Tailings Dam" Name/identifier
  • Q2. Location
  • Q3. Ownership
  • Q4. Status
  • Q5. Date of initial operation
  • Q6. Is the Dam currently operated or closed as per currently approved design?
  • Q7. Raising method
  • Q8. Current Maximum Height
  • Q9. Current Tailings Storage Impoundment Volume
  • Q10. Planned Tailings Storage Impoundment Volume in 5-years time.
  • Q11. Most recent Independent Expert Review
  • Q12. Do you have full and complete relevant engineering records including design, construction, operation, maintenance and/or closure.
  • Q13. What is your hazard categorisation of this facility, based on consequence of failure?
  • Q14. What guideline do you follow for the classification system?
  • Q15. Has this facility, at any point in its history, failed to be confirmed or certified as stable, or experienced notable stability concerns, as identified by an independent engineer (even if later certified as stable by the same or a different firm).
  • Q16. Do you have internal/in house engineering specialist oversight of this facility? Or do you have external engineering support for this purpose?
  • Q17. Has a formal analysis of the downstream impact on communities, ecosystems and critical infrastructure in the event of catastrophic failure been undertaken and to reflect final conditions? If so, when did this assessment take place
  • Q18. Is there a) a closure plan in place for this dam, and b) does it include long term monitoring?
  • Q19. Have you, or do you plan to assess your tailings facilities against the impact of more regular extreme weather events as a result of climate change, e.g. over the next two years?
  • Q20. Any other relevant information and supporting documentation.

Phase 2 and Future Plans.

We intend for this database to be a global hub, providing up to date and reliable information on tailings storage facilities, in the public interest.

To date we have focused on information provided by publicly listed companies, but would welcome disclosures from private or state owned entities.

Phase 2 of the project includes work by Catapult Satellite Applications to test remote monitoring of dams using Synthetic Aperture Radar (SAR) satellites. The project also aims to increase the number of dams described, as while the first round of disclosures has captured many of the world’s largest tailings dams there are still many more out there – both active and legacy sites, some of which may be “orphaned”, where it is not clear who carries responsibility (the actual number of tailings dams is debated with estimates ranging from 3,500 to 33,000).

The Investor Mining and Tailings Safety Initiative, along with the International Council on Mining and Metals, and UN Environment, is also calling for a new global standard for safer management of tailings storage facilities, which is being developed via an independent process: the Global Tailings Review. The Investor Mining and Tailings Safety Initiative is also working with insurers, banks, and the wider investment industry on additional ways to improve safety and accountability in the mining industry.


The Investor Mining and Tailings Safety Initiative and UNEP are in the process of appointing a management board to guide the future direction of this portal. The appointed members will also be responsible for working with stakeholders to update the disclosure questions and to align them with the Global Mine Tailings Standard, due for release in mid-2020.

Technical team

The technical team consists of staff from GRID-Arendal, the University of Sydney, and Catapult Satellite Application (Phase 2 SAR application), supported by academics and industry professionals from a range of institutions and companies. The members of the Technical Team have developed the portal and will continue to work with the Management Board to incorporate stakeholder feedback and expand the content and functionality of the portal.

Navigating the site

Text to be added soon..


The original data contains inconsistencies in reporting format and descriptors used (e.g. different consequent risk guidelines). We have dealt with these in a number of ways:

  • Question 2. All latitude and longitude positions have been converted to decimal degrees if not provided in this format
  • Question 5. Year of construction. When companies provide day/month/year, this has been simplified to year
  • Question 7. Raising method. When compacted outer shell is listed as raising method, this is changed to as dry stacking
  • Questions 9 and 10.Current storage and planned storage volume in 5 years. When companies have reported current volumes for individual dykes in a tailings storage facility and future volume estimates for the whole facility, we have divided the future planned storage volume between the individual dykes. When companies have reported several tailings dams under the same current storage and planned volume increase, these have been consolidated into a single facility.
  • Question 11. Most recent independent expert review. Answers have been simplified to year.
  • Question 13. What is your hazard categorisation of this facility, based on consequence of failure? The risk categories are not currently comparable, as more than 10 different risk guidelines for consequence rick categorisation have been reported. We are working to standardise these guidelines, at least for the highest risk categories.
  • Questions 17,18 and 19. When companies have reported their intent to undertake a formal analysis of downstream impact, develop a closure plan etc., we have reported their answer as a no in the current disclosure (a record of their intentions remain if they are included in the notes provided in question 20).

Downloading data

The original company disclosure information can be accessed at Church of England Inventor Mining and Tailings Safety Initiative.

The full database is also publicly available. In the near future you will be able to obtain the data directly from this site, however as this is the beta version of the database and not all companies have verified their data, we ask you to contact GRID-Arendal to obtain permission to download the TSF dataset and to receive notice of updates as they occur.


Mine tailings: Mine tailings are a major waste stream generated in mining operations. They are the waste material left over after the valuable component has been removed through processing. They include ground-up rock or sand, and the chemical reagents and process water used to extract the commodity.

Downstream, Centreline dam construction:

Differences between water-retention dams and tailing dams Source: GRID-Arendal

In pit disposal: Tailings are backfilled into open pit mines and therefore require no embankment to contain the material.

Dry stacking: Tailings are dewatered to produce a dry cake, which can be stacked.

Compacted outer shell: A type of filtered tailing storage, where dewatered tailings are contained within a compacted outer shell

Privacy & security

The portal follows the principles of “data protection first”, as required by the EU/EEA's General Data Protection Regulations (GDPR) which has been adopted by both UK and Norway by law. The project also adopts other guidance, standards and design principles outlined by the ICO and ENISA and other relevant bodies, aligning with the notions of ‘by design’ and ‘by default’ as key building blocks when considering data processing and investing in relevant best practice.

The security plan is be based on current best international practices (such as ISO:9001/ISO:27001/ISO:2500 frameworks).

Quality Control and Quality Assurance

1. GRID-Arendal have developed this first phase of a global tailings portal on behalf of the Investor Mining & Tailings Safety Initiative.

2. All information contained on this website is derived from publicly available sources from companies disclosing information on their tailings dams. This site is for general information use only. Information can change without notice and GRID-Arendal does not guarantee the accuracy of information on the website, including information provided by third parties, at any particular time.

3. This website does not provide investment advice and nothing on the site should be construed as being personalised investment advice for your particular circumstances.

4. Further updates will be made to the Portal to improve the functionality and design of the site and your constructive feedback is welcome. If you are a company referenced on this website and would like further information about the methodology used, or have any concerns about published information, then please contact us. us via the feedback form on the bottom of the website.

5. The spatial data is derived from the external resources, consequently GRID-Arendal is not liable for positioning inaccuracies, subsequent updates, errors, or omissions of data.

How to get in touch

We will endeavour to respond to all queries in a timely manner, and we commit to prioritising queries from the companies whose disclosures we have presented in the Portal.

Please contact [GRID-Arendal] email address if you have a query about the portal.

Please contact the Investor Mining and Tailings Safety Initiative [email] if you have a query that relates to the disclosure request that was sent by institutional investors.