Western australia's Battery and Critical Minerals Strategy 2024-2030 government-led strategy highlights the states potential for producing and processing minerals and elements essential to modern technologies and the global energy transition. However, exploration for these critical minerals remains challenging. To address this, the Geological Survey of Western australia has developed the Mineral Systems atlas (MSa), an online platform that compiles and disseminates spatial data to support exploration. The MSa enables the Critical Mineral Systems team to generate critical mineral prospectivity maps, which reduce search areas and enhances exploration efficiency. The approach of prospectivity analysis for critical minerals uses a mineral system-based, data-rich, knowledge-driven approach to create predictor maps reflecting evidence of geological processes linked to mineralisation. Each predictor map is rasterised at 1 km cell resolution, with each cell being assigned a relative prospectivity value calibrated using a data set of harmonised assay results from exploration drill holes. Fuzzy logic is employed to combine predictor maps into a final prospectivity map. The results of these maps are tested against known critical mineral resources in Western australia. While this methodology has several limitations, including sampling bias, data density variability, and reliance on input data quality, the resulting maps show a strong correlation with known mineral deposits and highlight areas for further exploration, while considerably reducing the search area of the State. The predictor maps and final prospectivity map are published on the MSa allowing users to recreate the map or combine this approach with their own data sets.