By Jack Caldwell - Mining Engineer - Robertson GeoConsultants

The CD containing some of the papers presented at the SME conference in Seattle two weeks ago has just appeared on my desk. There are at least twenty papers that I will read and write about. For now let me discuss the first to catch my attention, namely Waste Dump Site Selection by Using Fuzzy Vikor by A. Yazdani-Chamzini of the Islamic Azad University in Tehran.

He starts by noting that the following considerations affect a decision as to where to place the waste dump:

  • Financial considerations comprise the costs of establishing dump, roadway construction, waste material transportation and site rehabilitation.
  • Environmental considerations include the possibility of acid generation and reactivity, drainage requirement determined by analysis of groundwater discharge areas, the effects on biotypes, the existence of physical contamination of ground water by waste weathering, and the protection measures for the surrounding environment from contaminants by reclamation upgrading the physical character of mine waste dumps.
  • Safety considerations require geotechnical failure and structural stability analysis because the dump must be designed in such a way as to minimize erosion, migration of contaminants into environment and other failure possibilities.

Another list he provides includes these site selection considerations:

  • The waste rock volume removed through the exploitation period,
  • The dump capacity,
  • The horizontal and vertical distance between the source and the dump location,
  • The cost and type of waste rock haulage from the source to the dump site,
  • The effect exerted by waste rock disposal on the environment,
  • The final boundaries of the pit and methods of ore mining,
  • The ground condition of the dump site,
  • The chemical and physical properties of the waste rock,
  • Time, methods and cost of dump site preparation,
  • Demand for mine working reclamation,
  • The filtration effect of surface and ground water.

For those in love with lists, here is a third he provides of the main steps involved in multidecision making, which is the mainspring of fuzzy logic:

  • Establishing system evaluation criteria that relate system capabilities to goals;
  • Developing alternative systems for attaining the goals (generating alternatives);
  • Evaluating alternatives in terms of criteria (the values of the criterion functions);
  • Applying a normative multicriteria analysis method;
  • Accepting one alternative as ‘‘optimal’’ (preferred);
  • If the final solution is not accepted, gather new information and go into the next iteration of multicriteria optimization.

The author proceeds to explain the details of what he did to select site D. I won’t bore you with the maths or why Fuzzy Vikor is, in his opinion, the best approach. To be honest I was not able to discern what sets Fuzzy Vikor apart from normal old multi-criteria decision making methods or the use of fuzzy logic in general. No matter, if you want to read the paper, I suspect it will soon be available on the SME’s OneMine site.