Minerals exploration is conducted within an environment of ambiguity in the information and a high degree of uncertainty concerning success. In an extension and application of Tetlock (2005) the present research examined the impact of cognitive predispositions on the quality of minerals exploration decision-making. Utilising instruments specifically designed to assess thinking and judgement predispositions results indicate that for this sample (n=94) an enjoyment of rational thinking and the need for cognitive closure were predictive of lower estimated percentages of the likelihood of finding an exploitable deposit keeping geophysical data constant. Several counter-intuitive findings related to the relationship between likelihood and amount of expenditure were also found. The findings add further support to Tetlock's (2005) call to hold experts in all fields to account for the recommendations they make and to examine not just what they think but how they think.