The Chilean Ministry of Mining has established regulations for the approval of project design, construction, operation and closure of tailings dams. The new regulations, captured in Supreme Decree No. 248/2006, replace the previous decree dating back to 1970. New understanding of health and safety issues, environmental protection and utilization of natural resources triggered the need for an updated, new law. Additionally, advanced design has created a larger diversity in dams, requiring an updated law to regulate them.
Aim of the New Law
The aim of the new law is to set procedures for the approval of tailings dams projects and to establish requirements for the design, construction, operation and closure of tailings dams and disposition of their annexed installations to assure the safety of persons, property and environment.
Most Significant Developments
Among the most noteworthy changes that the new law offers:
- The new law considers all different conditions of the tailings, like thicker and filtering.
- The new legal concept of tailings dams now requires the possible recovery of large amounts of water.
- Tailings dams will be allowed to only deposit tailings and no other types of waste. Waste that was not included in the original permission given by the National Service of Geology and Mining cannot be disposed unless a new approval is granted.
- The provisions of the new decree apply to all new projects, but also to modifications of existing dams when those adjustments change the conditions under which they were originally approved.
Closure of Tailings Dams
As for the closure of tailings dams, the new regulation establishes two types of closure: temporary and permanent.
- Temporary closure applies to situations where the tailings dam ceases to operate for a period equal to or less than two years. In this event, under Article 39, the user of the tailings dam must take the necessary measures to avoid the risk of an accident, informing its measures to the National Service of Geology and Mining for approval. The Service must decide within a maximum period of fifteen working days.
- Permanent Closure: This is verified when the tailings dam ceases to operate for a period that exceeds two years or permanently by the mining enterprise decision. Under Title X of Supreme Decree No. 72 of 1985, the decision of closing the dam permanently must be accompanied by a Closure Plan.
