Boliden Mineral Ab's mine in Garpenberg, Dalarna is going through a massiveexpansion. The annual ore production is being increased from 1,4 million tons to 2,5million tons in less than two years period of time. Along this expansion thedepartment of mining techniques is administrating a project of optimizing the shortterm planning for the mining production. Garpenberg have since mid 90s storedinformation from all mining processes in a database.The information consists of time data from all the different activities required in themining process, for example charging, blasting, loading etc. The database also containstime data of delays that are affecting the production. The amount of data is massiveand has previously not been analyzed but is expected to provide answers to whatcausing inaccuracy in the short term planning. The project is focused on two separatemining areas, Dammsjön and Ramp mining in Lappberget. Dammsjön is an area that isseverely affected by poor rock quality and is experiencing massive deviations inactivity operation time and consequently deviations in mining cycle operation time.The ramp mining in Lappberget is performed under good conditions with good rockquality and has relatively few deviations in activity operation time and mining cycleoperation time. A comparison has been made of these two mining areas to see howmuch influence rock quality has on the process deviations.The result shows that poor rock quality is the major cause of the short term planningis not being met in a satisfying extent in Dammsjön. Rock quality is related todeviations in the mining process in Lappberget but reported delays have a moredominant image here compared to total deviations. It has also been revealed thatinformation about rock quality for different mining areas is not within the database.The object of the project was to find an improved method for short term planning forthe mining production. But in the current situation it is not justified to do so due tothe absence of information about rock quality for each mining area.