Automatic change propagation in an area-based open pit mine designer is disclosed. One example includes an economic shell receiver module to receive an economic shell. In addition a user input module receives a user parametric input denoting an open pit mine shape based on the economic shell. An open pit mine designer module automatically develops an open pit mine design from the user parametric input. The user input module receives an additional area to be incorporated into the open pit mine design. The open pit mine designer module automatically propagates the additional area into the open pit mine design to generate a modified open pit mine design.