Analysis of the impacts of slope angle variation on slope stability and NPV via two different final pit definition techniques

Chaves, Leonardo Soares; Carvalho, Luiz Alberto; Souza, Felipe Ribeiro; Nader, Beck; Ortiz, Carlos A.; Torres, Vidal; Câmara, Taís Renata; Napa-García, Gian Franco; Valadão, George Eduardo Sales

doi:10.1590/0370-44672019730011

Cited by 5 publications

(3 citation statements)

References 18 publications

(17 reference statements)

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“…Integrated Optimization also allows the evaluation of geometric issues, which affect the operational safety of the open pit. Chaves et al [14] carried out a study of the impact of the slope angle variation on the safety factor (SF) and NPV of the project. Twentyfive different simulations were performed, allowing the optimization of the SF with the maximization of the NPV.…”

Section: Improvements and Innovations In Integrated Optimization Appr...mentioning

confidence: 99%

A Case Study of Incorporating Variable Recovery and Specific Energy in Long-Term Open Pit Mining

Mata

Nader

Mazzinghy

2023

Mining

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Integrated Optimization can find optimized solutions for a project to define open pit and mine scheduling with greater reliability. This work aims to demonstrate how the insertion of geometallurgical variables can significantly change the financial return of a project. Two geometallurgical variables are considered in mine planning simulations. Specific energy corresponds to the energy consumed in the comminution of the ore, and process recovery measures the percentage of metal incorporated into the product. Three scenarios were developed considering an iron ore deposit. In the Base Case (BC) scenario, the recovery was fixed, and the specific energy of comminution was not considered. GeoMet1 considers the variable recovery varying for each block. GeoMet2 considered both recovery and specific energy as variables varying for each block. GeoMet1 and GeoMet2 presented Net Present Value (NPV), respectively, as 3.68% and 13.57% lower than the BC. This overestimation of the BC results can be viewed as an optimistic case of mine planning that is very common in the mining industry. These results show that the use of specific energy and recovery variables is fundamental to obtaining more reliable mine planning.

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Section: Improvements and Innovations In Integrated Optimization Appr...mentioning

confidence: 99%

A Case Study of Incorporating Variable Recovery and Specific Energy in Long-Term Open Pit Mining

Mata

Nader

Mazzinghy

2023

Mining

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“…Main components of mine-to-mill integration in a gold mine. Sources: [45][46][47][48][49][50][51][52][53].…”

Section: Physical Integration Concentrates Onmentioning

confidence: 99%

Assessing of Losses and Dilution Impact on the Cost Chain: Case Study of Gold Ore Deposits

2021

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The conditions of declining gold grade in the ore, increasing depth of excavation, and de-creasing unallocated stock of deposits make it necessary to develop efficient solutions for the mine-to-mill process, which have to be adapted to each specific mining plant and will optimizes production costs. Current research focuses on a case study that demonstrates how indicators of mining losses and dilution influence the variation of costs chain in the production cycle. The article examines the topical issue of determining the effects at the mine-to-mill stages due to changes in losses and dilution. The author’s approach to the formation of a mine-to-mill cost chain is proposed by integrating several cost estimation methods into the general cost estimation methodology. The estimation methodology is a compilation of factor analysis and cost engineering methods that take into account the change in costs due to the variation of losses and dilution. It was proven that with variations in losses and dilution, cost savings arise due to changes in the volume of work on ore averaging, ore transportation, and beneficiation. For the case of the Kuranakh ore field, there are no effects at the mining stage. The use of internal reserves by means of managing ore quality parameters allows reducing the costs per ton of processed rock mass along the entire production chain.

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“…As such, early ndings suggested the installation of an e cient drainage system might promote strength gains, enabling the re-design and optimization of the pit geometry, including reduction of costs, reduction of the risk of mass instability, and improvement of the operational safety of the mine. Additionally, literature ndings showed that the de nition of optimal slope geometries is not trivial (Chaves et al 2020) and more studies are needed to better understand how multiple and con icting elements can be combined to improve decision-making in open-pit mines (Golestanifar et al 2018). Several noted that optimization algorithms facilitate more rapid and reliable decision-making.…”

Section: Introductionmentioning

confidence: 99%

Slope geometry optimization considering groundwater drawdown scenarios at an open-pit phosphate mine, southeastern Brazil

Borges

Bacellar

Grasso³

et al. 2023

Environ Earth Sci

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The design of open-pit mines should balance safety and economy. However, safe geotechnical conditions generally involve redesigning the geometry of slopes and groundwater drawdown, signi cantly increasing the costs of mining operations. The use of numerical models to simulate groundwater drawdown and slope stability can be an alternative to assess cost-bene t trade-offs for decision-making. This study documents a mining plan using groundwater drawdown scenarios that illustrate how geotechnical, economic, and environmental indicators can be combined to obtain optimum slope geometry for open-pit mining. The optimization approach analyzed different scenarios of groundwater drawdown for the nal pit of a phosphate mine to improve the pit slopes stability. The groundwater simulation scenarios included the combination of deep horizontal drains and pumping wells. Stability analyzes using the limit equilibrium method were used to obtain the bench, inter-ramp, and overall factors of safety of different representative sections. The factors of safety obtained, the drawdown costs and the water table elevation of each section were selected as indicators for obtaining the optimal drawdown scenario using a multi-objective tool. The groundwater control system obtained with 11 horizontal drains and 1 pumping well was considered the most adequate from the geotechnical and economic perspectives. Slope geometry optimization obtained with this drawdown scenario led to adequate inter-ramp and overall safety factors for the nal pit design, reducing the barren-to-ore ratio to 0.38, much less than the present ratio (≈ 3). The results are important for optimizing the slope geometry of open-pit mines and can be replicated in other regions.

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Analysis of the impacts of slope angle variation on slope stability and NPV via two different final pit definition techniques

Cited by 5 publications

References 18 publications

A Case Study of Incorporating Variable Recovery and Specific Energy in Long-Term Open Pit Mining

A Case Study of Incorporating Variable Recovery and Specific Energy in Long-Term Open Pit Mining

Assessing of Losses and Dilution Impact on the Cost Chain: Case Study of Gold Ore Deposits

Slope geometry optimization considering groundwater drawdown scenarios at an open-pit phosphate mine, southeastern Brazil

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