prédécoupage

OBS: [...] on utilise pour les tirs de mines la technique de prédécoupage : dans la roche on fore verticalement une série de trous de mines. Ceci provoquera une fissure verticale entre le massif de matériau exploité et le terrain qui amortira les ondes de chocs créés par les coups de mines du front de taille.

CONT: The intention of presplitting is to attain the same advantages as with smooth blasting. As opposed to smooth blasting, presplitting is used to blast the contour holes before the actual round is fired. Presplitting produces a crack in the rock between the contour holes at which the rock then loosens during the subsequent bench blasting. Because the holes are so closely spaced, crack formation follows the rows of holes and the holes themselves form crack indications. This means that uncharged holes between charged holes can improve the result when so required ...