This information has been put together in response to the Investor Mining and Tailings Safety Initiative.
Our approach
Tailings storage facilities (“TSFs”) are a key part of our mining and processing operations and our goal is to ensure zero harm from them, as outlined in our Group Tailings Policy. Tailings management is part of our corporate risk management system and we have a structured and robust approach to the risk classification of our existing and planned TSFs. We evaluate the consequence to human and environmental health in line with the classification systems of the Australian National Committee on Large Dams (“ANCOLD”) and the Canadian Dam Association (“CDA”). We conduct regular internal and external audits to monitor, measure and evaluate the effectiveness and safety of our TSFs. The results of these audits are reported back to site, Senior Management and the Board on a regular basis.
| 1. "Tailings Dam" Name/identifier |
Sabadola-Massawa Mine | Ity Mine | Houndé Mine | Mana Mine | Kalana Mine |
| 2. Location | 13°12'42"N, 12°11'53"W |
6°52'36"N, 8°07'33"W |
11°25'3.28'' N, 3°32'31.40'' W |
11°57'20'' N, 3°24'46'' W |
10°48'04.89"N 8°11.5'50.91"W |
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3. Ownership |
Owned and operated | Owned and operated | Owned and operated | Owned and operated | Owned |
| 4. Status | Active | Active | Active | Active | Inactive |
| 5. Date of initial operation |
March 2009 | 8 April 2019 | 1 November 2017 | 2008 | Commence operation in 2004 and halted operation in 2017, prior to acquisition by Endeavour. |
| 6. Is the Dam currently operated or closed as per currently approved design? |
Currently operated in accordance with operations manuals. Basis of Design ANCOLD (2019). | Currently operated in accordance with Knight Piesold (“KP”) operating manual – PE301-00505_19 TSF Operating Manual. | Currently operated in accordance with Knight Piesold (“KP”) operating manual – PE401-00067_14 TSF, WSD and WHD Operating Manual. | Currently operated in accordance with Knight Piesold (“KP”) operating manual – PE401-00018-A3001 TSF Operating Manual. | Currently under care and maintenance, project in redevelopment, subject to a DFS. Currently not closed. |
| 7. Raising method | Upstream | Downstream | Downstream | Stage 1 – 3 Upstream and Stage 4 Downstream. Stage 5 Modified Center Line |
Upstream |
| 8. Current maximum height | 26 m |
Wall height varies against natural topography. Average current wall height is 30.1 m. |
Wall height varies against natural topography. Average current wall height is 32.0 m. Maximum wall height is 35.0 m for Cell 1 and 30.0 m for Cell 2. |
Wall height varies against natural topography. Maximum current wall height is 21 m. |
11 m |
| 9. Current tailings storage impoundment volume | 48 Mt or 30.9 Mm3 (slurry settled density 1.55 t/m3). | 21 Mt or 19 Mm3 at 1.1 t/m3. | 22.77 Mt or 16.26 Mm3 (slurry settled density 1.2 t/m3). | 37.9 Mt or 27.1 Mm3 (slurry settled density 1.4 t/m3). | 0.64 Mt at 1.55 t/m3. |
| 10. Planned tailings storage impoundment volume in five years’ time | 60 Mt or 38.7 Mm3 (slurry settled density 1.55 t/m3). | TSF 1 = 11.2 Mt or 8.6 Mm3 (slurry settled density 1.3 t/m3). TSF 2 = 26.4 Mt (slurry settled density 1.3 t/m3. Total of 58.6 Mt or 45 Mm3 (slurry settled density 1.3 t/m3). |
50.6 Mt or 42.2 Mm3 (slurry settled density 1.2 t/m3). Expect to extend TSF at 31 Mt. | 50.8 Mt or 36.2 Mm3 (slurry settled density 1.4 t/m3). | N/A |
| 11. Most recent independent expert review |
Knight Piesold, August 2022 2022 independent ICMC audit completed. |
Knight Piesold, November 2022 2022 independent ICMC audit completed. |
Knight Piesold, August 2022 2022 independent ICMC audit completed. |
Knight Piesold, August 2022 2022 independent ICMC audit completed. |
Independent Audit planned for April 2023. |
| 12. Do you have full and complete relevant engineering records including design, construction, operation, maintenance and/or closure. |
Yes for Stages 1-5. Stage 4/5 construction completed in July 2020, report published. Operating manual refer to PE401-00067_14 TSF, WSD and WHD Operating Manual. |
Yes, for Stage 1 commissioned in March 2019 and for Stage 2 which was handed over in July 2020. Operating manual refer to PE301-00505_19 TSF Operating Manual. |
Yes. Operating manual refer to AC401-00077-05 TSF Operating Manual. |
Yes. Operating manual refer to PE401-00018-A3001 TSF Design for Construction. |
Yes, Closure plan refer to R_Kalana Mine Closure Plan 9112006. |
| 13. What is your hazard categorisation of this facility, based on consequence of failure? | High A (ANCOLD 2012) | High C (ANCOLD 2012) | High B (ANCOLD 2012) | High (CDA) | Low (ANCOLD 2019 and SANS 10286) |
| 14. What guideline do you follow for the classification system? | Australian National Committee on Large Dams (ANCOLD 2012) Guidelines. | Australian National Committee on Large Dams (ANCOLD 2012) Guidelines. | Australian National Committee on Large Dams (ANCOLD 2012) Guidelines. | Canadian Dam Association (“CDA"). | Australian National Committee on Large Dams (ANCOLD 2019) Guidelines |
| 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 | No | 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? | External – Knight Piesold (Perth) – which has been involved with each dam embankment raise since inception. | External – Knight Piesold (Perth) – which has been involved with each dam since inception. | External – Knight Piesold (Perth) – which has been involved with the dam since inception. | External – Knight Piesold (Perth). | External – Knight Piesold (Denver). |
| 17. Has a formal analysis of the downstream impact on communities, ecosystems and critical infrastructure in the event of catastrophic failure been undertaken and to reflect final conditions? If so, when did this assessment take place? | Yes. Undertaken in 2012. | Yes. Undertaken during 2017/2018 design period. | Yes. Undertaken April 2019. | Yes. Undertaken in 2007. | Yes. Undertaken in 2006 and contained in the Design Report by METAGO. |
| 18. Is there a) a closure plan in place for this dam, and b) does it include long-term monitoring? | Yes. Trials of vegetation have been completed. Detailed closure plan ongoing. | Closure plan concept developed for asset reclamation obligation. Detailed mine closure plan ongoing. | Provisional reclamation and closure plan of the Houndé mine performed by Socrege in February 2019. | Yes and yes. Detailed mine closure plan ongoing. | Yes, closure plan refer to R_Kalana Mine Closure Plan 9112006. |
| 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 next two years? | Yes. Freeboard volume more than sufficient to contain PMP. | Yes. Due to location within considerable high rainfall area (average >1.5 m pa), TSF is monitored with respect to catchment and wet season runoff from surrounding landscape. TSF is also monitored in the case of extreme weather conditions. Example, in the event of a 1 in 100 annual exceedance probability (AEP) wet season or 72 hr flood. |
Yes. TSF is monitored in the case of extreme weather conditions. Example 1 in 100 AEP wet season or 72 hr flood. | Yes. Freeboard volume more than sufficient to contain PMP. | Yes, climate change study in progress, outcomes of which will inform AEP assessment by the Engineer of Record. |
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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. |
External support provided by independent consultant with more than 30 years’ experience in West Africa in addition to the design consultant. |
Dam has a clay lining and a HDPE liner. There are monitoring bores around the dam and piezometers in the walls. TSF has been designed with underdrainage and a leakage collection and recovery system (“LCRS”). There is zero evidence of any leakage. |
Dam has a clay lining and a HDPE liner. There are monitoring bores around the dam and piezometers in the walls. TSF has been designed with underdrainage and a leakage collection and recovery system (“LCRS”). There is zero evidence of any leakage. |
Owned and operated by subsidiary SEMAFO Burkina Faso S.A. Q16: Limited internal expertise. We rely on external support (geotechnical engineering firm). |
Sustainability Report 2023
Read about our ESG strategy and the significant sustainability milestones reached in 2023.
