A Multi-Criteria Procedure for Selecting Mechanical Excavation Methods

Abstract

This paper presents the results of a technical and economic analysis of the process of obtaining aggregates by mechanical excavation using hydraulic hammers, vibration rippers, Wirtgen surface miners, and ripper-dozers. The analysis involved a number of machine performance tests carried out at the “Raciszyn” Jurassic limestone deposit. The values determined in the tests included the average performance of individual devices making up the process system, unit fuel consumption and particle size distribution curves. These data served as inputs for the economic analysis of mechanical excavation and aggregate production methods. The method with the smallest unit production cost was determined. As different mechanical excavation methods affect not only the costs of obtaining aggregates, but also other non-economic values, Bellinger’s multi-criteria procedure was used to determine the optimal method. Bellinger’s multi-criteria procedure of selecting the mechanical excavation method may prove to be a useful optimisation tool, although one that requires knowledge of a given industry and its processes. Its advantage lies in relative simplicity and ease of use. This procedure should facilitate the preliminary assessment of selecting the most optimal technology and the assessment of the risk of choosing the least optimal one. The precision and, consequently, the objectivity, of the conducted analysis depends on the number and quality of the adopted criteria, which are largely connected with the knowledge level of the decision maker. On the basis of the authors’ assumptions, the most optimal mechanical excavation method at the “Raciszyn” Jurassic limestone deposit is the Wirtgen surface miner. The main advantage of this procedure is the optimal fragmentation of the excavated material and the low unit cost of aggregate production.