Evaluation of mineral deposits in terms of grade and quantity is done based on information obtained through geological investigations carried out in the area. Conventional and statistical methods are adopted, involving creation, standardization, and validation of the geological database, preparation of interactive geological model, geostatistical analysis, block modelling, and block-wise estimations. In a view to standardize the process uniform across the world, United Nations has framed guidelines for each stage of the exploration, though individual countries have their own specific guideline followed. Under these guidelines, any resource is estimated based on three major factors covering geology (G), feasibility (F), and economic viability (E). Reconnaissance, prospecting, General Exploration, and Detailed exploration are the four axes ascertaining geological confidence. The feasibility involves three axes, namely geological studies, pre-feasibility studies, and feasibility studies. The economic viability is determined under three axes, namely intrinsically economic, potentially economic, and economic. These aspects include the deposit’s geological setting, mineralization characteristics, the economic inputs and risk analysis, including other related aspects such as mining, metallurgical, marketing, legal, environmental, social, and political. The outcome of the process is categorization under mineral resource and mineral reserves. Mineral Resources are further subclassed as measured, pre-feasibility, and feasibility Resources, while mineral reserves are categorized as Probable and Proved Reserve. Based on the confidence level, further activities are decided which culminate to short-term and long-term mine planning and estimation of life of mine (LOM).