Assessing sustainable development, especially of the mining and minerals sector, is a challenge. This paper is an attempt to address this challenge by developing a methodology using fuzzy logic that encompasses the definitions, fundamentals, economic underpinnings and criteria of sustainable development. The paper starts by distinguishing the newly conceptualized ‘assessment for sustainability’ from the generally practiced ‘sustainability assessment’, framework, clarifying that the former looks at the process in question and lays out the path to be followed to assess sustainability, while the latter is just a static report. It then highlights the inherent limitations of the three traditional sustainability assessment tools and attempts to improve upon these limitations by proposing a model using fuzzy logic, weak sustainability criteria and context-dependent sustainability indicators to assess sustainable development of the mining and minerals sector. As an illustration, the paper demonstrates how the proposed methodology can be applied to a reference town, where mining is the primary economic activity. The results derived can be used internally for identification of ‘hot spots’ as well as externally for sustainability reporting and stakeholder engagement. Assessment for sustainability also facilitates monitoring, estimating the degree of sustainability and defines a course of action for stakeholders as well as policy-makers to improve a project's degree of sustainability. Copyright © 2011 John Wiley & Sons, Ltd and ERP Environment.