Novel At-Face-Slurry Performance Modeling with Elliptical and Spherical Geometries

Raymond S. Suglo, Samuel Frimp

Abstract

Surface mine production scheduling and sequencing are used to maximize the expected profit and investment returns from mining operations. The pit geometries and expansion rates, and the periodic volume of materials from different benches in a multi-bench, multi-face open pit mine determine the equipment requirements, which impact the maximize just-in-time (JIT) production decisions. The analytical geometric volume calculations require time lags that prevent rapid information for JIT decisions. The introduction of the novel At-Face-Slurry (AFS) oil sands method require fast, accurate and repeatable pit volume estimation using continuous flow process. The first part of this paper shows how partial differential equations (PDEs) and geometric techniques were used in modeling material volume, as well as pit layout changes with circular and elliptical geometries of an oil sands mine. The second part contains the economic analysis on the current mining system (CMS) and the cyclic excavator conveyor belt control system (CycEx CBCS). A continuous flow process via PDEs was used to model material volume, as well as pit layout changes with circular and elliptical geometries of an oil sands mine and compared with analytical geometric methods. PDEs were used in the modeling due to the continuous nature of the changes in the volumes of the pits with time. The geometric and PDEs values are similar for the pit configurations. This work represents the first successful attempt at using PDE in geometric calculations for open pit mines. The economic analysis shows that the NPV of the current mining system (CMS) is $3.2×1010 while that for the cyclic excavator conveyor belt control system (CycEx CBCS) is $4.06×1010. The Profitability Index (PI) for the CMS and CycEx CBCS options are 19.37 and 43.37 respectively. The IRR of the CMS option is 29.02% while that of the CycEx CBCS option is 33.37%. The DPBP for the CMS and CycEx CBCS options are 3.24 months and 1.92 months, respectively. The CMS option has an operating cost of $1.386/tonne ($2.774/barrel) while that of the CycEx CBCS option is $0.779/tonne ($1.558/barrel). The requirement for a fast, accurate and repeatable process for generating pit volumes is met by using PDEs.