The art of decision making is pivotal to effective project management. For more than twenty-four years we performed real-time decision making, risk assessments, valuations and comparisons during industry-related trade-off studies, benchmarking, mine optimisation, operations improvement, equipment performance, mineability studies, capital and operating cost studies with the aid of Tacmin's business performance improvement system. During every stage of the project lifecycle, project managers face a huge array of choices. Furthermore, elements of decision analysis such as analysis of potential alternatives and assessment of project risk are critical during each stage of the project lifecycle. Currently, there are no standard procedures that would sufficiently cover all the multiple-criteria requirements along with a breakdown into the preliminary and main assessment. However, at Tacmin the entire foundation required was created, such as definitions of requirements to an assessment method, selection and accurate description of the various assessment criteria and classification of the target system for typical mining project decision-making problems.