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The Çayeli copper-zinc deposit is located in northeastern Turkey, approximately seven kilometres from the Black Sea in the Büyük Dere Valley. Mining activity in this area dates back to the 1930s, and there are records of activity on the Çayeli deposit from as early as 1950. The Mineral Research and Exploration Institute of Turkey (MTA) drilled 45 holes between 1967 and 1975 which defined the orebody. Mineral rights for the property were transferred to Etibank in the late 1970s, and in 1981 they formed a joint venture with Phelps Dodge, creating a new company: Çayeli Bakir Isletmeleri A.S.

Phelps Dodge subsequently sold its interest to Metall Mining (presently Inmet Mining). The project set out to develop an underground copper/zinc mine in the Black Sea region with associated concentrator and infrastructure. Çayeli would be Turkey's largest underground mine with private sector majority shareholding and first to be established as a foreign operated joint venture. Production began at the mine in 1994 and was expected to produce an average of 103,000 tonnes per annum (tpa) of copper concentrate and 64,000 tpa zinc concentrate, with an estimated mine life of 15 years.

Overview

Submarine tailings disposal was an attractive option for this mine because of the proximity of the Çayeli copper-zinc deposit to the Black Sea. The keys to successful use of this option were placing the tailings as deep as was technically possible to avoid disturbing the fisheries and tourist industry of the coastline, and identifying a pipeline route that minimised the risk of pipeline failure due to seismic activity.

Experience

Rescan was initially retained by the International Finance Corporation of the World Bank to evaluate submarine tailings placement for the proposed Çayeli Bakir mine, and to conduct environmental impact studies of the proposed disposal system. Subsequently, Çayeli Bakir Isletmeleri A.S. retained Rescan to provide a conceptual design for a submarine tailings disposal system and predict its effect on the environment. The resulting pipeline was designed to transport a combined effluent of tailings, mine water and sewage for discharge at 350 m depth in the Black Sea. This is currently the world’s deepest submarine tailings outfall.