Gold Recovery from Cyanide-Based Leach Solutions Using Zinc Cementation: A Case of Small-scale Gold Mining in Zimbabwe

Rachiel Bvurire; Kupakwashe Lindsay Mahamba; Yemurai Vengesa; Sharrydon Bright; Hlanganipai Ngarivume

doi:doi:10.11648/j.ijmpem.20251004.14

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Gold Recovery from Cyanide-Based Leach Solutions Using Zinc Cementation: A Case of Small-scale Gold Mining in Zimbabwe

Rachiel Bvurire

, Kupakwashe Lindsay Mahamba

, Yemurai Vengesa

, Sharrydon Bright

, Hlanganipai Ngarivume^*

Published in International Journal of Mineral Processing and Extractive Metallurgy (Volume 10, Issue 4)

Received: 12 September 2025 Accepted: 23 September 2025 Published: 29 October 2025

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Abstract

The small-scale gold mining sector (SSGM) in Zimbabwe is a significant contributor to the country’s economy, at 12% of total exports. Although official output figures are rising, the general belief is that most of the small-scale gold production is unaccounted for, as it only reports gold produced from amalgamation and carbon adsorption, which the Government monitors through Statutory Instruments. However, gold produced from unregulated methods often ends up in illicit gold trading, with Zinc cementation being one of the unregulated gold recovery methods that small-scale gold miners rampantly abuse due to its ease of filtration and low cost. Governing legislation or Statutory Instruments for control of Zinc cementation are non-existent, creating easy loopholes for abuse and strong links to illicit financial flows. This study investigates the feasibility of regularising Zinc cementation as a gold recovery method for small-scale operations in Zimbabwe, ensuring effective monitoring and surveillance. Optimum parameters for Zinc cementation were determined experimentally. The determination of optimum parameters for Zinc cementation was done using a 2³ fractional factorial design and gold deportment analysis was conducted using samples from a small-scale gold mine located on the early Precambrian, Bulawayan, andesitic and dacitic meta-volcanic geological formation in Zimbabwe’s Matabeleland mining region. The influence of free cyanide concentration, dissolved oxygen concentration and pH on gold recovery was evaluated. Experimental work showed the feasibility of using Zinc Cementation as a possible recovery route for gold in SSGM with optimum parameters of: - pH value 11.5, free cyanide concentration 0.05g/L and dissolved oxygen concentration of 0.5ppm. The analysis showed that pH and Oxygen concentration increase gold recovery by a factor of 40%, with pH having the most significant effect on gold recovery. The study concludes that Zinc Cementation for small-scale hydrometallurgical gold extraction is an effective recovery method and should be regularised by the Government through a Statutory Instrument for easier monitoring and surveillance. Further studies on various ores from different provinces are recommended to incorporate diverse mineralogical differences into the design. Additionally, setting up a pilot plant to refine the metallurgical plant requirements for controlling zinc cementation is suggested.

Published in	International Journal of Mineral Processing and Extractive Metallurgy (Volume 10, Issue 4)
DOI	10.11648/j.ijmpem.20251004.14
Page(s)	130-142
Creative Commons	This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.
Copyright	Copyright © The Author(s), 2025. Published by Science Publishing Group

Keywords

Zinc Cementation, Gold, Cyanide, Leaching, Small-scale Mining

References

[1]	R. Mapuranga, "The contribution of small scale mining to Zimbabwean economy," Mining Zimbabwe, p. 1, 16 October 2020.
[2]	M. Hunter, "Follow the money: Zimbabwe: A Rapid assesment of gold supply chains and financial flows linked to Artisanal and Small Scale gold mining in Zimbabwe," United Nations Industrial Development Organisation, April 2018.
[3]	M. Nyoni, "Zimbabwe: Gold smuggling syndicates exposed," The Standard, Harare, 2021.
[4]	F. Njini and G. Marawanyika, "Zimbabwe Gold smugglers shipping over US$ 1.5billion a year," Bloomberg, 24 November 2020.
[5]	S. Jeon, S. Bright, I. Park, A. Kuze, M. Ito and N. Hiroyoshi, "A kinetic study on enhanced cementation of gold ions by galvanic interactions between Aluminium(Al) as an electron donor and Activated carbon (AC)as an electeon mediator Ammonium thiosulphate system," minerals mdpi, vol. 12, no. 91, pp. 1-12, 2022. https://doi.org/10.3390/min12010091
[6]	M. Adams, Gold Ore Processing, Project development and Operations, 2nd Edition, London: Elsevier, 2016.
[7]	A. L. Mular, D. Halbe and D. Barratt, Mineral Processing Plant Design, Practice and Control Proceedings, Colorado, USA: Society for Mining, Metallurgy and Exploration, 2002.
[8]	J. Marsden and C. House, The Chemistry of Gold extraction, Colorado USA: Society for Mining, Metallurgy and Exploration, 2006.
[9]	G. Martinez, J. T. Parga, J. Valencuela Garcia, G. Tiburcio Munive and Gonzalez Zamarippa, "Kinetic aspects of gold and silver recovery in Cementation with Zinc powder and Electrocoagulation Iron Process," Advances in Chemical Engineering and Science, no. 2, pp. 342-349, 2012. https://doi.org/10.4236/ACES.2012.23040
[10]	C. Fleming, "Hydrometallurgy of Precious metal recovery," Hydrometallurgy, vol. 30, pp. 127-162, 1992. https://doi.org/10.1016/0304-386X(92)90081-A
[11]	S. Vilchis-Carbajal, I. Gonzalez and G. Lapidus, "An electrochemical study of gold cementation with Zinc Powder at low cyanide concentration in alkaline solutions," Journal of Applied Electrochemistry, vol. 30, pp. 217-229, 2000. https://doi.org/10.1023/A:1003820807315
[12]	G. Chi, M. C. Fuerstenau and J. Marsden, "Study of Merrill Crowe Processing Part 1: Solubility of Zinc in alkaline cyanide solutions," International Journal of Mineral Processing, vol. 49, pp. 171- 183, 1997. https://doi.org/10.1016/S0301-7516(96)00043-9
[13]	I. Yahiaoui and F. Aissani-Benissad, "Experimental design for copper cementation process in a fixed bed reactor using two-level factorial design," Arabian Journal of Chemistry, vol. 3, pp. 187- 190, 2010. https://doi.org/10.1016/j.arabjc.2010.04.009
[14]	D. C. Montgomery, Design and Analysis of Experiments, 9th Edition ed., Arizona State University: John Wiley and Sons, 2017.
[15]	D. Selvamathu and D. Dipayan, Introduction to Statistical Methods, Design of Experiments and Statistical Quality control, Singapore: Springer Nature Singapore, 2018.

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Bvurire, R., Mahamba, K. L., Vengesa, Y., Bright, S., Ngarivume, H. (2025). Gold Recovery from Cyanide-Based Leach Solutions Using Zinc Cementation: A Case of Small-scale Gold Mining in Zimbabwe. International Journal of Mineral Processing and Extractive Metallurgy, 10(4), 130-142. https://doi.org/10.11648/j.ijmpem.20251004.14

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ACS Style

Bvurire, R.; Mahamba, K. L.; Vengesa, Y.; Bright, S.; Ngarivume, H. Gold Recovery from Cyanide-Based Leach Solutions Using Zinc Cementation: A Case of Small-scale Gold Mining in Zimbabwe. Int. J. Miner. Process. Extr. Metall. 2025, 10(4), 130-142. doi: 10.11648/j.ijmpem.20251004.14

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AMA Style

Bvurire R, Mahamba KL, Vengesa Y, Bright S, Ngarivume H. Gold Recovery from Cyanide-Based Leach Solutions Using Zinc Cementation: A Case of Small-scale Gold Mining in Zimbabwe. Int J Miner Process Extr Metall. 2025;10(4):130-142. doi: 10.11648/j.ijmpem.20251004.14

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@article{10.11648/j.ijmpem.20251004.14,
  author = {Rachiel Bvurire and Kupakwashe Lindsay Mahamba and Yemurai Vengesa and Sharrydon Bright and Hlanganipai Ngarivume},
  title = {Gold Recovery from Cyanide-Based Leach Solutions Using Zinc Cementation: A Case of Small-scale Gold Mining in Zimbabwe
},
  journal = {International Journal of Mineral Processing and Extractive Metallurgy},
  volume = {10},
  number = {4},
  pages = {130-142},
  doi = {10.11648/j.ijmpem.20251004.14},
  url = {https://doi.org/10.11648/j.ijmpem.20251004.14},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijmpem.20251004.14},
  abstract = {The small-scale gold mining sector (SSGM) in Zimbabwe is a significant contributor to the country’s economy, at 12% of total exports. Although official output figures are rising, the general belief is that most of the small-scale gold production is unaccounted for, as it only reports gold produced from amalgamation and carbon adsorption, which the Government monitors through Statutory Instruments. However, gold produced from unregulated methods often ends up in illicit gold trading, with Zinc cementation being one of the unregulated gold recovery methods that small-scale gold miners rampantly abuse due to its ease of filtration and low cost. Governing legislation or Statutory Instruments for control of Zinc cementation are non-existent, creating easy loopholes for abuse and strong links to illicit financial flows. This study investigates the feasibility of regularising Zinc cementation as a gold recovery method for small-scale operations in Zimbabwe, ensuring effective monitoring and surveillance. Optimum parameters for Zinc cementation were determined experimentally. The determination of optimum parameters for Zinc cementation was done using a 23 fractional factorial design and gold deportment analysis was conducted using samples from a small-scale gold mine located on the early Precambrian, Bulawayan, andesitic and dacitic meta-volcanic geological formation in Zimbabwe’s Matabeleland mining region. The influence of free cyanide concentration, dissolved oxygen concentration and pH on gold recovery was evaluated. Experimental work showed the feasibility of using Zinc Cementation as a possible recovery route for gold in SSGM with optimum parameters of: - pH value 11.5, free cyanide concentration 0.05g/L and dissolved oxygen concentration of 0.5ppm. The analysis showed that pH and Oxygen concentration increase gold recovery by a factor of 40%, with pH having the most significant effect on gold recovery. The study concludes that Zinc Cementation for small-scale hydrometallurgical gold extraction is an effective recovery method and should be regularised by the Government through a Statutory Instrument for easier monitoring and surveillance. Further studies on various ores from different provinces are recommended to incorporate diverse mineralogical differences into the design. Additionally, setting up a pilot plant to refine the metallurgical plant requirements for controlling zinc cementation is suggested.
},
 year = {2025}
}

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TY  - JOUR
T1  - Gold Recovery from Cyanide-Based Leach Solutions Using Zinc Cementation: A Case of Small-scale Gold Mining in Zimbabwe

AU  - Rachiel Bvurire
AU  - Kupakwashe Lindsay Mahamba
AU  - Yemurai Vengesa
AU  - Sharrydon Bright
AU  - Hlanganipai Ngarivume
Y1  - 2025/10/29
PY  - 2025
N1  - https://doi.org/10.11648/j.ijmpem.20251004.14
DO  - 10.11648/j.ijmpem.20251004.14
T2  - International Journal of Mineral Processing and Extractive Metallurgy
JF  - International Journal of Mineral Processing and Extractive Metallurgy
JO  - International Journal of Mineral Processing and Extractive Metallurgy
SP  - 130
EP  - 142
PB  - Science Publishing Group
SN  - 2575-1859
UR  - https://doi.org/10.11648/j.ijmpem.20251004.14
AB  - The small-scale gold mining sector (SSGM) in Zimbabwe is a significant contributor to the country’s economy, at 12% of total exports. Although official output figures are rising, the general belief is that most of the small-scale gold production is unaccounted for, as it only reports gold produced from amalgamation and carbon adsorption, which the Government monitors through Statutory Instruments. However, gold produced from unregulated methods often ends up in illicit gold trading, with Zinc cementation being one of the unregulated gold recovery methods that small-scale gold miners rampantly abuse due to its ease of filtration and low cost. Governing legislation or Statutory Instruments for control of Zinc cementation are non-existent, creating easy loopholes for abuse and strong links to illicit financial flows. This study investigates the feasibility of regularising Zinc cementation as a gold recovery method for small-scale operations in Zimbabwe, ensuring effective monitoring and surveillance. Optimum parameters for Zinc cementation were determined experimentally. The determination of optimum parameters for Zinc cementation was done using a 23 fractional factorial design and gold deportment analysis was conducted using samples from a small-scale gold mine located on the early Precambrian, Bulawayan, andesitic and dacitic meta-volcanic geological formation in Zimbabwe’s Matabeleland mining region. The influence of free cyanide concentration, dissolved oxygen concentration and pH on gold recovery was evaluated. Experimental work showed the feasibility of using Zinc Cementation as a possible recovery route for gold in SSGM with optimum parameters of: - pH value 11.5, free cyanide concentration 0.05g/L and dissolved oxygen concentration of 0.5ppm. The analysis showed that pH and Oxygen concentration increase gold recovery by a factor of 40%, with pH having the most significant effect on gold recovery. The study concludes that Zinc Cementation for small-scale hydrometallurgical gold extraction is an effective recovery method and should be regularised by the Government through a Statutory Instrument for easier monitoring and surveillance. Further studies on various ores from different provinces are recommended to incorporate diverse mineralogical differences into the design. Additionally, setting up a pilot plant to refine the metallurgical plant requirements for controlling zinc cementation is suggested.

VL  - 10
IS  - 4
ER  -

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Author Information

Rachiel Bvurire

Department of Mining, University of Zimbabwe, Harare, Zimbabwe

Contact Email

http://orcid.org/0009-0001-5513-5987
Kupakwashe Lindsay Mahamba

Department of Metallurgical Engineering, Gwanda State University, Filabusi, Zimbabwe

Contact Email

http://orcid.org/0009-0003-3933-0103
Yemurai Vengesa

Department of Mining, University of Zimbabwe, Harare, Zimbabwe

Contact Email

http://orcid.org/0000-0001-8737-1565
Sharrydon Bright

Department of Mining, University of Zimbabwe, Harare, Zimbabwe

Contact Email

http://orcid.org/0000-0003-3856-0946
Hlanganipai Ngarivume

Department of Metallurgy, Zimbabwe School of Mines, Bulawayo, Zimbabwe

Contact Email

http://orcid.org/0009-0008-0880-750X

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APA Style

Bvurire, R., Mahamba, K. L., Vengesa, Y., Bright, S., Ngarivume, H. (2025). Gold Recovery from Cyanide-Based Leach Solutions Using Zinc Cementation: A Case of Small-scale Gold Mining in Zimbabwe. International Journal of Mineral Processing and Extractive Metallurgy, 10(4), 130-142. https://doi.org/10.11648/j.ijmpem.20251004.14

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ACS Style

Bvurire, R.; Mahamba, K. L.; Vengesa, Y.; Bright, S.; Ngarivume, H. Gold Recovery from Cyanide-Based Leach Solutions Using Zinc Cementation: A Case of Small-scale Gold Mining in Zimbabwe. Int. J. Miner. Process. Extr. Metall. 2025, 10(4), 130-142. doi: 10.11648/j.ijmpem.20251004.14

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AMA Style

Bvurire R, Mahamba KL, Vengesa Y, Bright S, Ngarivume H. Gold Recovery from Cyanide-Based Leach Solutions Using Zinc Cementation: A Case of Small-scale Gold Mining in Zimbabwe. Int J Miner Process Extr Metall. 2025;10(4):130-142. doi: 10.11648/j.ijmpem.20251004.14

Copy | Download

@article{10.11648/j.ijmpem.20251004.14,
  author = {Rachiel Bvurire and Kupakwashe Lindsay Mahamba and Yemurai Vengesa and Sharrydon Bright and Hlanganipai Ngarivume},
  title = {Gold Recovery from Cyanide-Based Leach Solutions Using Zinc Cementation: A Case of Small-scale Gold Mining in Zimbabwe
},
  journal = {International Journal of Mineral Processing and Extractive Metallurgy},
  volume = {10},
  number = {4},
  pages = {130-142},
  doi = {10.11648/j.ijmpem.20251004.14},
  url = {https://doi.org/10.11648/j.ijmpem.20251004.14},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijmpem.20251004.14},
  abstract = {The small-scale gold mining sector (SSGM) in Zimbabwe is a significant contributor to the country’s economy, at 12% of total exports. Although official output figures are rising, the general belief is that most of the small-scale gold production is unaccounted for, as it only reports gold produced from amalgamation and carbon adsorption, which the Government monitors through Statutory Instruments. However, gold produced from unregulated methods often ends up in illicit gold trading, with Zinc cementation being one of the unregulated gold recovery methods that small-scale gold miners rampantly abuse due to its ease of filtration and low cost. Governing legislation or Statutory Instruments for control of Zinc cementation are non-existent, creating easy loopholes for abuse and strong links to illicit financial flows. This study investigates the feasibility of regularising Zinc cementation as a gold recovery method for small-scale operations in Zimbabwe, ensuring effective monitoring and surveillance. Optimum parameters for Zinc cementation were determined experimentally. The determination of optimum parameters for Zinc cementation was done using a 23 fractional factorial design and gold deportment analysis was conducted using samples from a small-scale gold mine located on the early Precambrian, Bulawayan, andesitic and dacitic meta-volcanic geological formation in Zimbabwe’s Matabeleland mining region. The influence of free cyanide concentration, dissolved oxygen concentration and pH on gold recovery was evaluated. Experimental work showed the feasibility of using Zinc Cementation as a possible recovery route for gold in SSGM with optimum parameters of: - pH value 11.5, free cyanide concentration 0.05g/L and dissolved oxygen concentration of 0.5ppm. The analysis showed that pH and Oxygen concentration increase gold recovery by a factor of 40%, with pH having the most significant effect on gold recovery. The study concludes that Zinc Cementation for small-scale hydrometallurgical gold extraction is an effective recovery method and should be regularised by the Government through a Statutory Instrument for easier monitoring and surveillance. Further studies on various ores from different provinces are recommended to incorporate diverse mineralogical differences into the design. Additionally, setting up a pilot plant to refine the metallurgical plant requirements for controlling zinc cementation is suggested.
},
 year = {2025}
}

Copy | Download

TY  - JOUR
T1  - Gold Recovery from Cyanide-Based Leach Solutions Using Zinc Cementation: A Case of Small-scale Gold Mining in Zimbabwe

AU  - Rachiel Bvurire
AU  - Kupakwashe Lindsay Mahamba
AU  - Yemurai Vengesa
AU  - Sharrydon Bright
AU  - Hlanganipai Ngarivume
Y1  - 2025/10/29
PY  - 2025
N1  - https://doi.org/10.11648/j.ijmpem.20251004.14
DO  - 10.11648/j.ijmpem.20251004.14
T2  - International Journal of Mineral Processing and Extractive Metallurgy
JF  - International Journal of Mineral Processing and Extractive Metallurgy
JO  - International Journal of Mineral Processing and Extractive Metallurgy
SP  - 130
EP  - 142
PB  - Science Publishing Group
SN  - 2575-1859
UR  - https://doi.org/10.11648/j.ijmpem.20251004.14
AB  - The small-scale gold mining sector (SSGM) in Zimbabwe is a significant contributor to the country’s economy, at 12% of total exports. Although official output figures are rising, the general belief is that most of the small-scale gold production is unaccounted for, as it only reports gold produced from amalgamation and carbon adsorption, which the Government monitors through Statutory Instruments. However, gold produced from unregulated methods often ends up in illicit gold trading, with Zinc cementation being one of the unregulated gold recovery methods that small-scale gold miners rampantly abuse due to its ease of filtration and low cost. Governing legislation or Statutory Instruments for control of Zinc cementation are non-existent, creating easy loopholes for abuse and strong links to illicit financial flows. This study investigates the feasibility of regularising Zinc cementation as a gold recovery method for small-scale operations in Zimbabwe, ensuring effective monitoring and surveillance. Optimum parameters for Zinc cementation were determined experimentally. The determination of optimum parameters for Zinc cementation was done using a 23 fractional factorial design and gold deportment analysis was conducted using samples from a small-scale gold mine located on the early Precambrian, Bulawayan, andesitic and dacitic meta-volcanic geological formation in Zimbabwe’s Matabeleland mining region. The influence of free cyanide concentration, dissolved oxygen concentration and pH on gold recovery was evaluated. Experimental work showed the feasibility of using Zinc Cementation as a possible recovery route for gold in SSGM with optimum parameters of: - pH value 11.5, free cyanide concentration 0.05g/L and dissolved oxygen concentration of 0.5ppm. The analysis showed that pH and Oxygen concentration increase gold recovery by a factor of 40%, with pH having the most significant effect on gold recovery. The study concludes that Zinc Cementation for small-scale hydrometallurgical gold extraction is an effective recovery method and should be regularised by the Government through a Statutory Instrument for easier monitoring and surveillance. Further studies on various ores from different provinces are recommended to incorporate diverse mineralogical differences into the design. Additionally, setting up a pilot plant to refine the metallurgical plant requirements for controlling zinc cementation is suggested.

VL  - 10
IS  - 4
ER  -

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