The mining industry is crucial for global economic growth but faces environmental challenges, especially in designing stable rehabilitated landforms. To tackle these issues, rainfall simulators have been recognized for their value in providing data for erosion modeling and analysis, aiding the development of effective land cover systems for long-term stability. This chapter provides an overview of the theory, specifications, and design principles of rainfall simulators. It explores the detailed design and construction of a well-known model, along with its calibration process ensuring accurate rainfall production and distribution. The chapter also discusses raindrop size distribution and associated kinetic energy calculations. Calibration results demonstrate satisfactory outcomes with Christiansen’s uniformity coefficient exceeding 85% and a median raindrop size of 2.15 mm. The device successfully generates desired kinetic energy for simulated rainstorms, crucial for studying soil erosion. Examples highlight the application of rainfall simulators in evaluating erosion stability in Queensland mines. Efforts to construct a soil erosion database for 34 open-cut mines in Queensland using a similar portable rainfall simulator are highlighted. This database contributes to developing user-friendly MINErosion models, providing estimates of soil erosion/deposition at different scales to support the Australian mining sector.