ABSTRACT
The efforts assigned to the application of contour blasting in underground and surface operations are fully justified for technical. The pressure of the gases is a key element in the execution of a contour blasting, and for this reason it should be maintained until the cracks of adjacent blast-holes meet, which can be achieved by adequate stemming height to avoid escape of the gases into the atmosphere. There are many different techniques for contour blasting that have been developed from the fifties, but nowadays the most commonly used are: Pre-splitting, Cushion blasting, Buffer blasting and Line-drilling. The first charges used for contour blastings were dynamite cartridges with a detonating cord and spaced to acheive the desired charge density. In large diameter contour blastings, the decoupling of loose poured ANFO is achieved in a very effective way with plastic tubes or cartridges, but this is a very expensive and tedious method: on other occasions, wooden air spacers are used.
