MORE than half the top 50 mining companies have disclosed which of their tailings dams around the world pose “extreme” or “very high” risks to life and the environment should they collapse.

The news comes after pressure from the Church of England Pensions Board and other major investors for transparency.

In April, the Pensions Board and the Swedish Council on Ethics for the AP Funds, supported by 96 other investors, gave 683 listed extractives companies 45 days to disclose the extent of their use of tailing storage facilities (News, 12 April). The letter followed the collapse of a dam operated by Vale in Brumadinho, in Brazil, in January, killed more than 200 people (News, 8 February).

On Monday, it was announced that, out of 655* companies contacted, 202 responded, of which 118 confirmed that they did not have tailings facilities; 77 confirmed that they did; 30 companies did not disclose, or asked for extra time; and 453 did not respond.

Of the top 50 mining companies, 29 had published information about thousands of individual tailings dams and facilities on company websites.This included Vale, BHP, Anglo American, Barrick Gold, Freeport-McMoRan, and Glencore.

The chief executive of Vale, Eduardo Bartolomeo, reported that the company would spend $1.9 billion on decommissioning upstream dams. “Vale is going through a critical moment that has created opportunities to identify and reconfirm the company’s priorities: safety, people, and repair,” he said.

BHP listed eight of its tailing dams — the hypothetical collapse of which would have “extreme” consequences under the Canadian Dam Association guidelines. This rating means that a dam failure could result in more than 100 deaths, besides causing permanent damage to the environment, infrastructure, and economy.

BHP classed a further 16 dams as posing a “very high” risk of hazard, meaning that a collapse would probably kill more than ten but fewer than 100 people.

Glencore extreme-rated 14 of its dams, and a further 25 were rated as very high-risk. The company said that it was analysing concerns at 17 of its sites, including fortifying dams in Zambia and Kazakhstan, and carrying out remedial work at its sites in Peru.

Anglo American uses a different rating system. It classed 21 of its 91 dams as posing a “major” risk: the equivalent of more than ten deaths and permanent environmental damage in the rate of collapse.

A global review of tailing dams is being led by the Swiss former Environment Minister, Professor Bruno Oberle. It is being co-convened by the International Council of Mining and Metals, the Principles for Responsible Investment, and the United Nations Environment Programme.

The director of ethics and engagement for the C of E Pensions Board, Adam Matthews, said: “We are grateful for the prompt and serious response by a significant number of major mining companies, and pleased by the detail contained within their disclosures.

“It is important to remember this is the first step of gathering information on the locations, size, and condition of tailings dams, and that the details will be fed into the independent review of tailings dams chaired by Professor Oberle. The next stage is to review the list of companies that have not supplied disclosures.”

He continued: “Good tailings management exists, but when tailings dams fail, the consequences can be catastrophic for communities and the environment. These disclosures bring a new level of transparency to the mining sector that will enable us to begin to reappraise the risk in our portfolios.

“It is clear there has been insufficient attention paid by the investment community, and tailings have, in effect, been treated as an externality. These disclosures begin to change that understanding. We now know who has a facility, where it is, and we are beginning to understand the risks associated with individual dams.”

The secretary-general of the Council on Ethics of the Swedish National Pension Funds, John Howchin, said: “Not disclosing is unacceptable and poses a very real risk to our investment. We are now working with partners to develop a global tailings database that can standardise independent reporting and monitoring of tailings.”

* The number is lower than that announced in April, owing to changes during the period of engagement, e.g. because of acquisitions or delisting.