CAML operates tailings storage facilities at the Sasa mine in North Macedonia.
Sasa tailings storage facilities
There are five facilities at site, all owned and managed by Sasa.
|Location (Gauss Kruger coordinate system)||Y=7,626,188; X=4,664,211||Y=7,626,384; X=4,663,656||Y=7,626,777; X=4,663,584||Y=7,627,228; X=4,663,165||Y=7,627,601; X=4,662,437|
|In operation||1964-1974||1974-1990||1990-2003, 2006-2007||2007-current||From 2019 with capacity to 2025/26|
|Current tailings storage volume (Mm3)||1.4||4.8||4.9||4.9||–|
|Planned 5 year tailings storage volume (Mm3)||As above||As above||As above||5.2||1.7|
All Sasa facilities are of downstream construction, which is widely viewed in the industry as the safest design.
Downstream facilities begin with a ‘starter wall’. Tailings are discharged into the dam and cyclone such that the fine component (slimes) flows into the ponded section and the coarse fraction (sands) flows in the opposite direction to create the ongoing raise in the dam wall.
Downstream design tailings storage facilities are typically suitable for areas with seismic activity and high rainfall. In addition, all tailings dams must be designed to take into account the specific environmental setting in which they are to be located, which will include grain size, slope angle and height of dam wall above the pond.
Review and monitoring of Sasa tailings storage facilities
Sasa’s tailings dams have been constructed in line with North Macedonian standards. The monitoring data generated from analysis of the tailings facilities is regularly reviewed by Stip University, which produces monthly reports for the mine.
In 2016, Golder Associates (global tailings dam experts) undertook an audit and review of the facilities at Sasa and, in February 2019, CAML instructed that group to perform a third-party stability review of the tailings facilities. The Group will continue to use external consultants regularly to review its storage facilities.
SRK Consulting has developed closure plans for Sasa, which include closure of the tailings storage facilities. Long term monitoring procedures of the older facilities are already in place, and future mine closure plans and requirements include regular tailings dam monitoring. Formal analysis of the downstream impact on communities, ecosystems and infrastructure has also been undertaken by the Faculty of Civil Engineering in Skopje, North Macedonia and by SRK Consulting.