The purpose of this paper is to introduce the use of Ulrich’s Critical Systems Heuristics to organize second order critical reflexion in systems practice and action research. It is argued that such an approach not only improves the rigour of systems methodology in action in a specific ‘situation of interest’, but brings rigour to research aimed at improving systems practice through the process of meta-evaluation. The paper draws on critical systems thinking and illustrates its application in the context of an intervention using Checkland’s Soft Systems Methodology (SSM) to evaluate the environmental impact of mining operations in southern Peru. The SSM application is used to explore the way that ‘second order’ boundary critique can be used to assess the researcher’s expectations and its impact in re-designing the methodology itself or the way the methodology is used. We sketch the context in which the systemic intervention was carried out reporting on the initial initials SSM stages( Relevant Systems, Root definitions and CATWOE analysis) produced in a workshop that took place in February 2011 in Southern Peru..Reflection on how to prepare and then apply SSM was gained by using the framework. More tests are required to develop fully a 2nd order boundary critique tool; and further research of applications in similar contexts is needed to refine the critique.