Reducing Uncertainties in Gold Plant Design and Operations

Charles Amoah; Grace Ofori-Sarpong; Richard Kwasi Amankwah

doi:doi:10.11648/j.ijmpem.20210603.14

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Reducing Uncertainties in Gold Plant Design and Operations

Charles Amoah, Grace Ofori-Sarpong, Richard Kwasi Amankwah

Published in International Journal of Mineral Processing and Extractive Metallurgy (Volume 6, Issue 3)

Received: 1 September 2021 Accepted: 16 September 2021 Published: 27 September 2021

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Abstract

The conventional way of designing a plant is to determine the characteristics of rocks in terms of crushability, grindability and other properties that affect the mill throughput. These properties are most of the time determined from drill cores obtained during the exploration period. Such initial exploration campaigns drill to levels shallower than the real pit that will be developed. Thus, as mining pits become deeper, the ore characteristics change and begin to impact negatively on the expected mill throughput. Such situations necessitate modification of the plant, and the first intervention usually is to supplement the initial energy input with additional size reduction equipment to achieve the required throughput. However, reconsidering the inputs used in determining the initial plant selection would help in reducing the setbacks during the operational period. To help reduce uncertainties and develop a predictive tool, this study considered a greenfield drilled up to 273 m, and the core samples obtained were tested to ascertain the variations in Bond work index to depths beyond 500 m. The study showed that within the section of the Asankragwa belt investigated, Bond work indices increased from 10.3 kW/t at the surface to 16.5 kW/t at a depth of 273 m. The Bond work index was established as a function of vertical depth in a pit (x) with the relation BWI=6E-05x2 + 0.0071x + 9.8816. The predicted value at 280 m was 16.3 kW/t while that of the blend was 15.8 kW/t, giving an error of 4%. This novel relationship between the BWI and depth predicts the BWI beyond 500m with minimum mean square error. The use of the novel Bond work index and depth relationship will eliminate the uncertainty beyond the drilled depth and give a clear understanding of what the rock characteristics will be as pits become deeper. In addition, a savings of US$62,500 per diamond drill hole and US$25,000 per one reverse drilling after the 250 m depth can be made by the use of this model. This can result in massive savings considering the number of holes that would have to be drilled across the length of the pit.

Published in	International Journal of Mineral Processing and Extractive Metallurgy (Volume 6, Issue 3)
DOI	10.11648/j.ijmpem.20210603.14
Page(s)	67-72
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), 2021. Published by Science Publishing Group

Keywords

Bond Work Index (BWI), Asankragwa Belt, Plant Operations, Uncertainties, All in Sustaining Cost (AISC)

References

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APA Style

Charles Amoah, Grace Ofori-Sarpong, Richard Kwasi Amankwah. (2021). Reducing Uncertainties in Gold Plant Design and Operations. International Journal of Mineral Processing and Extractive Metallurgy, 6(3), 67-72. https://doi.org/10.11648/j.ijmpem.20210603.14

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ACS Style

Charles Amoah; Grace Ofori-Sarpong; Richard Kwasi Amankwah. Reducing Uncertainties in Gold Plant Design and Operations. Int. J. Miner. Process. Extr. Metall. 2021, 6(3), 67-72. doi: 10.11648/j.ijmpem.20210603.14

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AMA Style

Charles Amoah, Grace Ofori-Sarpong, Richard Kwasi Amankwah. Reducing Uncertainties in Gold Plant Design and Operations. Int J Miner Process Extr Metall. 2021;6(3):67-72. doi: 10.11648/j.ijmpem.20210603.14

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@article{10.11648/j.ijmpem.20210603.14,
  author = {Charles Amoah and Grace Ofori-Sarpong and Richard Kwasi Amankwah},
  title = {Reducing Uncertainties in Gold Plant Design and Operations},
  journal = {International Journal of Mineral Processing and Extractive Metallurgy},
  volume = {6},
  number = {3},
  pages = {67-72},
  doi = {10.11648/j.ijmpem.20210603.14},
  url = {https://doi.org/10.11648/j.ijmpem.20210603.14},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijmpem.20210603.14},
  abstract = {The conventional way of designing a plant is to determine the characteristics of rocks in terms of crushability, grindability and other properties that affect the mill throughput. These properties are most of the time determined from drill cores obtained during the exploration period. Such initial exploration campaigns drill to levels shallower than the real pit that will be developed. Thus, as mining pits become deeper, the ore characteristics change and begin to impact negatively on the expected mill throughput. Such situations necessitate modification of the plant, and the first intervention usually is to supplement the initial energy input with additional size reduction equipment to achieve the required throughput. However, reconsidering the inputs used in determining the initial plant selection would help in reducing the setbacks during the operational period. To help reduce uncertainties and develop a predictive tool, this study considered a greenfield drilled up to 273 m, and the core samples obtained were tested to ascertain the variations in Bond work index to depths beyond 500 m. The study showed that within the section of the Asankragwa belt investigated, Bond work indices increased from 10.3 kW/t at the surface to 16.5 kW/t at a depth of 273 m. The Bond work index was established as a function of vertical depth in a pit (x) with the relation BWI=6E-05x2 + 0.0071x + 9.8816. The predicted value at 280 m was 16.3 kW/t while that of the blend was 15.8 kW/t, giving an error of 4%. This novel relationship between the BWI and depth predicts the BWI beyond 500m with minimum mean square error. The use of the novel Bond work index and depth relationship will eliminate the uncertainty beyond the drilled depth and give a clear understanding of what the rock characteristics will be as pits become deeper. In addition, a savings of US$62,500 per diamond drill hole and US$25,000 per one reverse drilling after the 250 m depth can be made by the use of this model. This can result in massive savings considering the number of holes that would have to be drilled across the length of the pit.},
 year = {2021}
}

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TY - JOUR
T1 - Reducing Uncertainties in Gold Plant Design and Operations
AU - Charles Amoah
AU - Grace Ofori-Sarpong
AU - Richard Kwasi Amankwah
Y1 - 2021/09/27
PY - 2021
N1 - https://doi.org/10.11648/j.ijmpem.20210603.14
DO - 10.11648/j.ijmpem.20210603.14
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 - 67
EP - 72
PB - Science Publishing Group
SN - 2575-1859
UR - https://doi.org/10.11648/j.ijmpem.20210603.14
AB - The conventional way of designing a plant is to determine the characteristics of rocks in terms of crushability, grindability and other properties that affect the mill throughput. These properties are most of the time determined from drill cores obtained during the exploration period. Such initial exploration campaigns drill to levels shallower than the real pit that will be developed. Thus, as mining pits become deeper, the ore characteristics change and begin to impact negatively on the expected mill throughput. Such situations necessitate modification of the plant, and the first intervention usually is to supplement the initial energy input with additional size reduction equipment to achieve the required throughput. However, reconsidering the inputs used in determining the initial plant selection would help in reducing the setbacks during the operational period. To help reduce uncertainties and develop a predictive tool, this study considered a greenfield drilled up to 273 m, and the core samples obtained were tested to ascertain the variations in Bond work index to depths beyond 500 m. The study showed that within the section of the Asankragwa belt investigated, Bond work indices increased from 10.3 kW/t at the surface to 16.5 kW/t at a depth of 273 m. The Bond work index was established as a function of vertical depth in a pit (x) with the relation BWI=6E-05x2 + 0.0071x + 9.8816. The predicted value at 280 m was 16.3 kW/t while that of the blend was 15.8 kW/t, giving an error of 4%. This novel relationship between the BWI and depth predicts the BWI beyond 500m with minimum mean square error. The use of the novel Bond work index and depth relationship will eliminate the uncertainty beyond the drilled depth and give a clear understanding of what the rock characteristics will be as pits become deeper. In addition, a savings of US$62,500 per diamond drill hole and US$25,000 per one reverse drilling after the 250 m depth can be made by the use of this model. This can result in massive savings considering the number of holes that would have to be drilled across the length of the pit.
VL - 6
IS - 3
ER -

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Author Information

Charles Amoah

Asanko Gold Ghana Limited, Obotan Operations, Manso Nkran, Ghana
Grace Ofori-Sarpong

Department of Minerals Engineering, University of Mines and Technology, Tarkwa, Ghana
Richard Kwasi Amankwah

Department of Minerals Engineering, University of Mines and Technology, Tarkwa, Ghana

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Charles Amoah, Grace Ofori-Sarpong, Richard Kwasi Amankwah. (2021). Reducing Uncertainties in Gold Plant Design and Operations. International Journal of Mineral Processing and Extractive Metallurgy, 6(3), 67-72. https://doi.org/10.11648/j.ijmpem.20210603.14

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ACS Style

Charles Amoah; Grace Ofori-Sarpong; Richard Kwasi Amankwah. Reducing Uncertainties in Gold Plant Design and Operations. Int. J. Miner. Process. Extr. Metall. 2021, 6(3), 67-72. doi: 10.11648/j.ijmpem.20210603.14

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AMA Style

Charles Amoah, Grace Ofori-Sarpong, Richard Kwasi Amankwah. Reducing Uncertainties in Gold Plant Design and Operations. Int J Miner Process Extr Metall. 2021;6(3):67-72. doi: 10.11648/j.ijmpem.20210603.14

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@article{10.11648/j.ijmpem.20210603.14,
  author = {Charles Amoah and Grace Ofori-Sarpong and Richard Kwasi Amankwah},
  title = {Reducing Uncertainties in Gold Plant Design and Operations},
  journal = {International Journal of Mineral Processing and Extractive Metallurgy},
  volume = {6},
  number = {3},
  pages = {67-72},
  doi = {10.11648/j.ijmpem.20210603.14},
  url = {https://doi.org/10.11648/j.ijmpem.20210603.14},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijmpem.20210603.14},
  abstract = {The conventional way of designing a plant is to determine the characteristics of rocks in terms of crushability, grindability and other properties that affect the mill throughput. These properties are most of the time determined from drill cores obtained during the exploration period. Such initial exploration campaigns drill to levels shallower than the real pit that will be developed. Thus, as mining pits become deeper, the ore characteristics change and begin to impact negatively on the expected mill throughput. Such situations necessitate modification of the plant, and the first intervention usually is to supplement the initial energy input with additional size reduction equipment to achieve the required throughput. However, reconsidering the inputs used in determining the initial plant selection would help in reducing the setbacks during the operational period. To help reduce uncertainties and develop a predictive tool, this study considered a greenfield drilled up to 273 m, and the core samples obtained were tested to ascertain the variations in Bond work index to depths beyond 500 m. The study showed that within the section of the Asankragwa belt investigated, Bond work indices increased from 10.3 kW/t at the surface to 16.5 kW/t at a depth of 273 m. The Bond work index was established as a function of vertical depth in a pit (x) with the relation BWI=6E-05x2 + 0.0071x + 9.8816. The predicted value at 280 m was 16.3 kW/t while that of the blend was 15.8 kW/t, giving an error of 4%. This novel relationship between the BWI and depth predicts the BWI beyond 500m with minimum mean square error. The use of the novel Bond work index and depth relationship will eliminate the uncertainty beyond the drilled depth and give a clear understanding of what the rock characteristics will be as pits become deeper. In addition, a savings of US$62,500 per diamond drill hole and US$25,000 per one reverse drilling after the 250 m depth can be made by the use of this model. This can result in massive savings considering the number of holes that would have to be drilled across the length of the pit.},
 year = {2021}
}

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