The use of computer assisted system in the planning and operation in non-metallic mineral industry offers a variety of opportunities for rationalisation of work specifically in cement and lime industries. The practical use of new modelling techniques such as Digital Terrain modelling (DTM), Solid Modelling, Block Modelling and Geostatistical modelling, allow to evaluate deposit and to plan quarry effectively which result in finding best technical and economical solution from various alternatives taking into account any constrains specific to the operation. This paper explains these computer techniques used by commercial software and the self-developed systems. A description of the subsidiary aspects of the use of computer simulations of deposits is also given for simulation of excavation, simulation of loading and transport equipment and primary crushers. The results of the application in a limestone deposit in Turkey where production is planned to serve a lime plant are illustrated.