Natural Resources Research

, Volume 28, Issue 1, pp 153–171 | Cite as

Pilot Point Optimization of Mining Boundaries for Lateritic Metal Deposits: Finding the Trade-off Between Dilution and Ore Loss

  • Yasin DagasanEmail author
  • Philippe Renard
  • Julien Straubhaar
  • Oktay Erten
  • Erkan Topal
Original Paper


Geological contacts in lateritic metal deposits (footwall topographies) often delineate the orebody boundaries. Spatial variations seen in such contacts are frequently higher than those for the metal grades of the deposit. Therefore, borehole spacing chosen based on the grade variations cannot adequately capture the geological contact variability. Consequently, models created using such boreholes cause high volumetric uncertainties in the actual and targeted ore extraction volumes, which, in turn, lead to high unplanned dilution and ore losses. In this paper, a method to design optimum ore/mining boundaries for lateritic metal deposits is presented. The proposed approach minimizes the dilution/ore losses and comprises two main steps. First, the uncertainty on the orebody boundary is represented using a set of stochastic realizations generated with a multiple-point statistics algorithm. Then, the optimal orebody boundary is determined using an optimization technique inspired by a model calibration method called Pilot Points. The pilot points represent synthetic elevation values, and they are used to construct smooth mining boundaries using the multilevel B-spline technique. The performance of a generated surface is evaluated using the expected sum of losses in each of the stochastic realizations. The simulated annealing algorithm is used to iteratively determine the pilot point values which minimize the expected losses. The results show a significant reduction in the dilution volume as compared to those obtained from the actual mining operation.


Multiple-point statistics Direct sampling Bauxite mining Laterite simulated annealing Optimization Dig limit 



The authors would like to thank the editor and three anonymous reviewers for their valuable comments and suggestions.


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Copyright information

© International Association for Mathematical Geosciences 2018

Authors and Affiliations

  1. 1.Department of Mining and Metallurgical EngineeringWestern Australian School of Mines Curtin UniversityKalgoorlieAustralia
  2. 2.Centre for Hydrogeology and GeothermicsUniversity of NeuchâtelNeuchâtelSwitzerland

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