Abstract : Using an electro-mechanical drill working on the principle developed by J. Rand and H. Rufli, four holes have been drilled in different locations. In each of these drillings it has been observed that the core quality was excellent in the firn, but the ice, fractures appeared. Certain pieces of core were highly broken and sometimes core was completely sliced into irregular discs 1 or 2 cm thick. After a brief description of the drill, we describe the main phenomena observed and attempt to determine the possible causes of the fracturing.