The aim of the Master thesis was to optimize the drill- and blast work in the marble quarry Gummern of the Omya company. For that purpose in the first part of the Master thesis the actual status of the drill- and blast work was determined. This comprised also a detailed time study on a blast hole per blast hole basis. The analysis showed, that the drilling accuracy of the blast holes is quite high and that there is an optimization possibility as far as it concerns the length of the blast holes. The second part of the Master thesis comprised the change of the ignition procedure from top borehole ignition with detonating cord and electric detonators outside of the borehole to bottom borehole non electric ignition. A comparison of electric and non electric ignition showed that with the non electric ignition system 14 minutes per blast (about 88 hours per year) can be saved. The non electric ignition system also exhibits advantages in the handling with the detonators. In the third part of the Master thesis tests with bulk explosives (heavy ANFO and straight ANFO) supplied by Austin Powder GmbH and Westspreng GmbH were carried out. In the frame of the test blasts the advantages and disadvantages of the two different types of heavy ANFO trucks used were determined. With respect to the drill& blast pattern it could be shown that with the use of heavy ANFO 5.5 m of burden and 5.5. m of side spacing give a satisfying blast result .