DECISION SUPPORT RELATED TO THE MANAGEMENT AND CLOSURE OF TAILINGS STORAGE FACILITIES-GUIDELINE FOR THE HANDLING OF UNCERTAINTIES IN MODEL PREDICTIONS AND RISK BASED DECISION MAKING

摘要

Golder Associates, in conjunction with Fraser Alexander, the University of KwaZulu Natal and the University of Pretoria, developed a preliminary Decision Support System (DSS) for the sustainable design, operation and closure of metalliferous tailings storage facilities (TSF) on behalf of the Water Research Commission of South Africa. During the first phase of the project knowledge gaps were identified and these gaps were investigated further in the second phase. This paper reports on the findings of one of the identified gaps, namely the development of protocols to qualify, quantify and report uncertainty in specialist models.Regulators (and proponents) find it difficult to make decisions where liability is transferred (or responsibility accepted) and it is often due to lack of knowledge on how to identify uncertainties in impact predictions and assessments, how uncertainties should be quantified and expressed and how to make risk based decisions.There is a large amount of literature available on the subjects of uncertainty analysis, risk assessment and risk based decision making (RBDM), but there is not much guidance on how to bring all the concepts together when making a decision regarding the acceptability of a particular proposed TSF scheme.This research developed protocols and guidance to support the decision making processes captured in the DSS, specifically related to the water and surface stability aspects. The research provides a framework to qualify and quantify uncertainties in model simulations (especially predictions) and provides practical decision support guidance on how to make decisions based on predictions that have an element of uncertainty.