LONDON (Reuters) – Ethical investors working on a global standard for tailings dams have written to 683 listed resource companies, including major miners, asking for information to be made public within 45 days about every facility they control.

FILE PHOTO: A view of a collapsed tailings dam owned by Brazilian mining company Vale SA, in Brumadinho, Brazil February 10, 2019. REUTERS/Washington Alves/File Photo/File Photo

The safety of dams used to store mining waste, known as tailings, has gain prominence after the collapse of a Vale tailings dam in Brazil in January killed an estimated 300 people.

The International Council on Mining and Minerals (ICMM) industry group said in March it was working with the United Nations Environment Programme (UNEP) and the Principles for Responsible Investment (PRI)