The safety of the slopes during the open pit mining is very important and it not only has a great impact on the safety of the operation but also on the economy. The main purpose of this research was to assess the stability of a perlite mine in Monte Sparau, Sardinia using RS2 and Slope2 software to assess safety factors of the slopes and other geotechnical parameters. The main purpose was to assess the stability of the critical cross sections without reinforcement, to suggest likely failure mechanisms and to assess the overall reliability of the slopes. Perlite is a glassy volcanic rock containing water, which is used in construction, filtration, and other applications that require low density, high porosity and good thermal insulation.