Patent ID: 8214073

Claim:
A method of designing a drilling pattern for excavating a rock cavern, the drilling pattern determining at least the locations and hole direction angles of drill holes in a coordinate system of the drilling pattern and the lengths of the drill holes for a round to be drilled at a tunnel face, the method comprising: computer-aided designing of the drilling pattern by means of a drilling pattern design program, determination of a navigation plane for the drilling pattern; determination of at least an excavation profile for the cavern to be excavated, at least one group of holes inside the excavation profile, and a length of the drilling pattern on the basis of a length of the round to be excavated; determination of a plurality of drill holes for each group of holes; determination of starting locations at the navigation plane for the holes to be drilled; determination of the directions of the holes to be drilled from the starting locations to the bottoms of the holes; and the method further comprising determining, in the drilling pattern, a blast plane located at a bottom of the round at a distance corresponding to the length (L) of the pattern from the navigation plane; placing drill hole bottom locations at the bottom of the round at the blast plane; performing blasting calculation at the blast plane for at least some holes in the drilling pattern; utilizing blasting-technical data stored in advance in a memory for the blasting calculation; and supplying one of the following drill hole properties to the drilling pattern design program: drill hole start location at navigation plane, drill hole direction, and determining a missing second drill hole property on the basis of the location of the drill hole bottom and the supplied drill hole property, the drill hole properties being determined viewed from the bottom of the round towards the navigation plane.