EDITORIAL & OPINION — Tailings management critical for miners — Being prepared

Each time a mainstream journalist rounds up the usual suspects and prepares a report on mining practices worldwide, tailings dam failures are invariably stressed. Even though the articles generally show a poor understanding of science and usually contain many factual errors, they do drive home an important message: Mining companies must meet the challenge of tailings management if they are to achieve public support and acceptance for their environmental performance.

Fortunately, several initiatives are already under way to establish higher standards of performance. The Mining Association of Canada has published A Guide to the Management of Tailings Facilities, which covers each stage of tailings management, from design through construction, operation and then closure. The Environmental Protection Working Group on Mining and Metallurgy, a joint initiative of the International Council on Metals and the Environment (ICME) and the United Nations Environment Program (UNEP) have also identified tailings issues as one of the key challenges to achieving improvements in environmental performance.

ICME and UNEP jointly published a booklet, Case Studies Illustrating Environmental Practices in Mining and Metallurgical Processes, and hosted several international workshops on managing the risks of tailings disposal.

Reading the case studies is worthwhile, for each sheds light on the challenges faced by the industry, and the methods used to address a specific aspect of tailings management. There are plenty of success stories, but the authors do not mince words when they state that the impact on public safety and the environment from an embankment failure, or from seepage of contaminants, “can be disastrous.”

The call for accountability and responsibility is a serious one because so much can be destroyed so quickly. The density of tailings are such that the damage caused by a tailings spill is much more extensive than would be the case for a similar volume of water. Where water may flood a building, tailings can push it over and sweep it along with the flow.

After examining case studies worldwide, the report concludes that failures result from a lack of adequate application of known methods, bad designs, poor supervision during construction, or disregard of vital features that should have been incorporated at certain stages of construction. But it also makes the case that safe and environmentally acceptable dams can be built, and that the solution to public acceptance and higher performance standards lies in an integrated approach led by the industry itself.

One key message from United Nations officials is that companies should develop a co-ordinated plan to improve public preparedness in case of an accident. This allows the community, as well as the response organizations, to participate in preparing for emergencies. The author points out that if the community understands the real consequences of a spill before one occurs, it will be better prepared to deal with the emergency. If the community isn’t informed, mistrust and anxiety may lead to communication difficulties.

One of the case studies examines the emergency response during the 1995 Omai tailings dam failure in Guyana, and shows how prompt and appropriate action by on-site management and employees was able to reduce, by a significant extent, the initial impact and aftermath of the incident.

Local managers took immediate action when a haul-truck driver noted a stream of water coming from the tailings dam. Within 15 minutes of learning of the discharge, they put crews to work evacuating a diversion ditch to carry a major portion of the flow to the main mine pit. Over the next few days, a coffer dam was built to contain the remainder of the flow.

Shortly after the flow was detected, a speedboat was sent downstream to notify those living along the Essequibo River. Authorities were notified and invited to the site, and within hours, top executives flew to the mine site to confront the crisis and manage remediation efforts.

Subsequent investigations by the companies and the government concluded that the concentrations of cyanide from the spill were not injurious to health, owing to the high dilution capacity of the river and the natural degradation characteristics of cyanide. The only documented environmental damage was fish kill in the narrow Omai River, which flows past the mine and tailings dam into the Essequibo.

The managers and workers at Omai didn’t get much public praise for their prompt actions during this unfortunate incident. But they deserve it.