Multi-attribute fuzzy methodology for the selection of mining shovels

Mining shovels or excavators are basic equipment designed to dig and load material in surface mines. They are often considered the major material-handling equipment for high-production, low-cost operations (HPLC). The selection of an appropriate shovel for any HPLC operation is of critical importance because the overall production of the mine is measured in terms of material handled by a principal digging and loading equipment. A new multi-attribute fuzzy methodology for the selection of mining shovels for HPLC operations was developed. The fuzzy analysis included eight shovel selection categories with almost 60 objective and subjective attributes. The weight of each attribute was obtained by employing a pair-wise comparison. The final result of this fuzzy analysis is an overall fuzzy membership value or fuzzy score (FUZ-SCO). The methodology was incorporated in an expert system called shovel selection fuzzy expert system (SHS-FES) developed in Java and HTML programming languages. The SHS-FES allows for the assignment of an overall membership value to each of the shovel options and suggests to the mining experts a specific shovel that will satisfy given project requirements. A developed SHS-FES system was used to conduct a case study at an operating surface mine. Introduction There are two basic types of shovels: the hydraulic mining shovel (HMS) and the electric mining shovel (EMS). They have similar characteristics and routines when performing at a mine; however, there are few differences that could give an advantage to one over the other. These shovels require a high capital cost investment and could represent the costliest asset for mining operations (Agarwal, 1994; P&H MinePro, 2003). In an equipment selection process, in most cases, shovels are selected as a member within a fleet. Authors such as O’Shea (1964), Morgan and Peterson (1968), Mayer and Stark (1981), Easa (1988), Karshenas (1989), Jayawardane and Harris (1990), Huang and Kumar (1994) and Nagatani (2001) focused their efforts on the selection of a fleet rather than the sole selection of the excavator. The optimal shovel selection requires in-depth analysis of a series of characteristics or attributes that define both the excavator and the specific operation (Haidar et al., 1999). In other words, the excavator selection problem must be primarily approached by a comprehensive analysis of various equipment selection methodologies. Some of these methodologies consider selection attributes, which are linguistically focused and subjectively weighted, i.e., these attributes are not perfectly defined and are difficult to weigh (Kesimal and Bascetin, 2002). The identification of the factors or attributes affecting the excavator selection becomes important. Touran (1990) added that the selection methodology must be flexible and applicable to most types of problems directly related to surface mine machine selection. Most of the time, methodologies related to equipment selection lack flexibility when dealing with problems such as data transferring, process interaction, and specific input data change. Xing Xie (1997) indicated that the “type of operation” is the most significant concern when selecting any type of mining equipment. Mozumdar and Tiwari (1980) specified that the main mining considerations are mine planning, mine scheduling, supervision, mine design and marketing and noted that these are the drivers for equipment selection. Haidar et al. (1999) listed variables affecting equipment selection for surface mines in seven categories: Paper number TP-07-025. Original manuscript submitted June 2007. Revised manuscript accepted for publication December 2007. Discussion of this peer-reviewed and approved paper is invited and must be submitted to SME Publications Dept. prior to Sept. 30, 2009. Copyright 2008, Society for Mining, Metallurgy, and Exploration, Inc.