Abstarct: Due to increasing demand for raw materials and a significant reduction in surface reserves that can be exploited by opening operations, underground mining has become more important and is challenged by mine engineers. Underground mining methods are more dangerous and complex than surface mining and have higher mining costs. Also, there are various mining methods in underground mining due to several influential factors. Determination of the underground mining limit, stop layout and production scheduling are the most important issues in regard with underground mining. Numerous researchers have reported the influence of grade and economic uncertainty in open pit production planning. In contrast, a few effort has been done regarding underground mine planning under grade uncertainty condition that is one of the major components of technical uncertainty that affecting the variability of the project. Therefore, according to a new heuristic algorithm, a user-friendly computer program called Stop Layout Optimizer 3D (SLO3D) was developed using C# object-oriented programming in order to incorporate the influence of grade variability in final stop layout in three-dimensional space. Aloes, a mathematical programming approach was utilized and implemented on GAMS/CPLEX software in order to optimize the extraction sequence of generated stops in rigged model and 50 realizations obtained by Sequential Gaussian Simulation (SGS) method. baxsed on the results, the economic value obtained using SLO3D computer program was 15.62 M$ by kriging method and between 6.7 M$ to 30.7 M$ in grade uncertainty condition. Also, the worst and the best Net Present Value (NPV) obtained by solving proposed mathematical model for optimizing production scheduling under 18 time periods were 5.98 M$ and 27.34 M$ respectively. While, this value for kriged model was 13.86 M$. These variation ranges reflects the impact of grade uncertainty in underground mine planning.