Monitoring our Tailings Ponds

SEMAFO currently operates tailings facilities at its Boungou and Mana Mines in Burkina Faso. Boungou Mine embankments were built in 2017 using downstream mining methods. At Mana, tailings comprise an upstream spigot deposition type dam. Slurry discharge is carried out according to the beach slope level by keeping the sedimentary water in the center of the cell in use.

Each tailings facility is subject to regular internal inspections, including monitoring of dig stability through a series of piezometer wells installed on the facility. In addition, an external review of the tailings facilities is carried out on a biannual basis by a globally recognised engineering company in accordance with international guidelines. To date, we have not experienced any issues with our tailings facilities.

Mana's spigot and management system has proven reliable for the past 12 years of operations. In addition, management of central water at the dam eliminates water on the external embankments, thus protecting its berms.

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Boungou Mine Mana Mine
1. "Tailings dam" name/identifier A TSF with a single dam in L shape, and the opposite side hanging on the hill wall. A TSF consisting of 4 ring dykes and one central dyke
2. Location Lat 12°00'03'' N
Long 1°24'36'' W
Lat 11°57'20'' N
Long 3°24'46'' W
3. Ownership Owned and operated by subsidiary SEMAFO Boungou S.A. Owned and operated by SEMAFO Burkina Faso S.A.
4. Status Active Active
5. Date of initial operation 07/04/18 2008
6. Is the dam currently operated or closed as per currently approved design? Yes Yes
7. Raising method Downstream Upstream
8. Current maximum height 14.2m 17m
9. Current tailings storage impoundment volume 2,355,000 22,100,000
10. Planned tailings storage impoundment volume in 5 years time. 11,658,000 32,100,000
11.Most recent independent expert review N/A August 2017 (SNC Lavalin)
12. Do you have full and complete relevant engineering records including design, construction, operation,maintenance and/or closure. Yes Yes
13. What is your hazard categorisation of this facility, based on consequence of failure? HIGH B (ANCOLD) Refer to attached report entitled: "SMF_Summary of environment risk assessment.pdf"
14. What guideline do you follow for the classification system? Australian National Committee on Large Dams (ANCOLD) guidelines Canadian Dam Association (CDA)
15. Has this facility, at any point in its history, failed to be confirmed or certified as stable, or experienced notable stability concerns, as identified by an independent engineer (even if later certified as stable by the same or a different firm). No No
16. Do you have internal/in house engineering specialist oversight of this facility? Or do you have external engineering support for this purpose? Limited internal expertise - We rely on external support (geotechnical engineering firm) Limited internal expertise - We rely on external support (geotechnical engineering firm)
17. Has a formal analysis of the downstream impact on communities, ecosystems and critical infrastructure in the event of catastrophic failure been undertaken and toreflect final conditions? If so, when did this assessmenttake place? Yes - July 2018 Yes- 2007
18. Is there a) a closure plan in place for this dam, and
b) does it include long term monitoring?
Yes & Yes Yes & Yes
19. Have you, or do you plan to assess your tailings facilities against the impact of more regular extreme weather events as a result of climate change, e.g. over the nexttwo years? No No
20. Any other relevant information and supporting documentation. Please state if you have omitted any other exposure to tailings facilities through any joint ventures you may have. N/A N/A