Small scale-tests have been performed on magnetic mortar blocks to investigate the influence of delay times, specific charge and firing pattern on fragmentation both when the burden is free and when confined by debris simulating the confined conditions of a SLC-blast ring and to study the burden behavior during blasting by implementing dynamic methods of measurements. The dimensions of the test blocks were 660 ×270 ×210 mm (L ×W ×H). Two different blast hole patterns, 2 rows with 5 holes with a burden of 70 mm (S/B ×1.6) and 3 rows with 7 holes with a burden of 58.3 mm (S/B ×1.4). A complete analysis regarding the influence of different delay times ranging from 0 to 4.1 ms/m of burden, different specific charges and different firing patterns on fragmentation has been made, based upon 22 blocks.