Method for excavating a working face by blasting

A method for drilling cut holes in a working face having one free surface and for loading electric detonators therein, the method comprising the steps of:

• drilling a number of V-holes at a predetermined angle either in a horizontal angle cut pattern or in a vertical angle cut pattern around a central zone of the working face;
• drilling a number of parallel cut holes within an area surrounded by said said V-holes in the working face;
• and
• loading an electric detonator and an explosive material in the V-holes and the parallel cut holes, wherein the explosive material is loaded in said parallel cut holes from a bottom line of the parallel cut holes up to a bottom line of the V-holes by indirect priming.

A method for blasting cut holes in a working face having one free surface comprising steps of:

• blasting V-holes in order to form a slanted free surface;
• blasting center parallel cut holes in a central region of the slanted free surface in order to form a funnel-shaped free surface;
• and
• sequentially blasting middle parallel cut holes and outer parallel cut holes formed around the funnel-shaped free surface to form a cubical space.

A method for excavating a working face comprising steps of:

• drilling a number of V-holes at a predetermined angle either in a horizontal angle cut pattern or in a vertical angle cut pattern about a center zone of the working face, and drilling a number of parallel cut holes within an area surrounded by said V-holes in the working face, and drilling parallel cut spreader holes, stoping holes and contour holes in an area outside of the parallel cut holes;
• loading an electric detonator in the V-holes and loading an explosive material by direct priming in the parallel cut hole up to the bottom of the slant holes and loading said cut spreader holes, stoping holes, and contour holes;
• blasting the V-holes to form a slanted free surface;
• blasting center cut holes of the parallel cut holes to form a funnel-shaped free surface;
• sequentially blasting middle cut holes and outer cut holes of the parallel cut holes to form a cubical space;
• and
• sequentially blasting said cut spreader holes, stoping holes, and contour holes.

A method of excavating a specific area of a working face having one free surface according to excavation conditions, the method comprising steps of:

• drilling a plurality slanted hole pairs at predetermined angles on the specific area the working face, bottoms of the slanted hole pairs being spaced apart at a bottom line of the slanted hole pairs;
• drilling a plurality of parallel cut holes within a portion of the working face, including center parallel cut holes, having a bottom line which extends beyond the bottom line of the slanted hole pairs;
• loading explosive materials in the slanted hole pairs;
• and
• loading explosive materials in the center parallel cut holes from the bottom line of the center parallel cut holes up to the bottom line of the slanted hole pairs.