Mining Goes Digital – Mueller et al. (Eds)
© 2019 Taylor & Francis Group, London, ISBN 978-0-367-33604-2
279
Break line and shotpile surfaces modeling in design
of large-scale blasts
S.V. Lukichev, O.V. Nagovitsyn & A.S. Shishkin
Mining Institute KSC RAS, Apatity, Russian Federation
ABSTRACT: A software tool for designing open pit large-scale blasts has been developed
based on the mining and geological information system MINEFRAME. The given software allows predicting a location of the break line and shotpile surface taking into account
the dynamic nature of the rock mass damage and interaction of borehole charges. For this
purpose, imitation modelling was used, which allowed mathematical description of the rock
mass damage, formation of break lines and shotpile surface of a fractured rock mass. The
article describes an algorithm for large-scale blast modelling and shows the examples which
confirm a good accordance between the simulation and a real blast.
Keywords: break line, shotpile, open pit large-scale blast, short-delay explosion, imitation
simulation, block model
1 INTRODUCTION
At present, damage of rocks by with borehole charge blasting is one of the most common
ways of preparing the rock mass to excavation. The costs of loading, transportation and
processing of minerals depend on the quality of rock preparation to blasting. At the same
time, the blast damage is an integrated and expensive technological process. When designing
blasting operations, it is necessary to take into account a significant number of variables, the
main ones of which are the elastic-strength characteristics of rocks, the energy characteristics
of explosive charges and their spatial arrangement. In this connection, the task of verifying
a design solution based on computer modelling of blasting the borehole charges in the rock
mass is an urgent issue.
To the moment, in Russia there are two software products which implement the algorithms for 3D simulating large-scale blasts of borehole charges with the formation of rock
mass shotpile. These are BLAST MAKER [1] and GEOMIX [2]. The BLAST MAKER’s
mathematical model of a blast is based on hydrodynamic equations; GEOMIX calculates
the blast action of borehole charges by using a velocity field, which is determined based on
their potential.
To determine the velocity potential at the charge-rock mass boundary, the time integral is
calculated for the dependence that relates the maximum pressure of the blasting products in
an explosive cavity with the velocities of detonation, a longitudinal wave in the rock mass and
density of explosives and rocks. The pressure in an explosive cavity is calculated on the basis
of time dependence, which relates the density and velocity of detonation of explosives, the
geometry of the charge and the stemming. The critical value of the rock mass displacement
velocity was adopted as a criterion for the rock mass damage.
To implement the 3D design schemes, the authors use a method of forming a regular grid
area, for each cell of which the potential is calculated and the area of damage and break line
are assessed. At the stage of dispersion of detached rocks along a ballistic trajectory and the
formation of a shotpile, the exchange of materials between the individual cells of the grid
area is monitored [3].
© 2019 Taylor & Francis Group, London, ISBN 978-0-367-33604-2
279
Break line and shotpile surfaces modeling in design
of large-scale blasts
S.V. Lukichev, O.V. Nagovitsyn & A.S. Shishkin
Mining Institute KSC RAS, Apatity, Russian Federation
ABSTRACT: A software tool for designing open pit large-scale blasts has been developed
based on the mining and geological information system MINEFRAME. The given software allows predicting a location of the break line and shotpile surface taking into account
the dynamic nature of the rock mass damage and interaction of borehole charges. For this
purpose, imitation modelling was used, which allowed mathematical description of the rock
mass damage, formation of break lines and shotpile surface of a fractured rock mass. The
article describes an algorithm for large-scale blast modelling and shows the examples which
confirm a good accordance between the simulation and a real blast.
Keywords: break line, shotpile, open pit large-scale blast, short-delay explosion, imitation
simulation, block model
1 INTRODUCTION
At present, damage of rocks by with borehole charge blasting is one of the most common
ways of preparing the rock mass to excavation. The costs of loading, transportation and
processing of minerals depend on the quality of rock preparation to blasting. At the same
time, the blast damage is an integrated and expensive technological process. When designing
blasting operations, it is necessary to take into account a significant number of variables, the
main ones of which are the elastic-strength characteristics of rocks, the energy characteristics
of explosive charges and their spatial arrangement. In this connection, the task of verifying
a design solution based on computer modelling of blasting the borehole charges in the rock
mass is an urgent issue.
To the moment, in Russia there are two software products which implement the algorithms for 3D simulating large-scale blasts of borehole charges with the formation of rock
mass shotpile. These are BLAST MAKER [1] and GEOMIX [2]. The BLAST MAKER’s
mathematical model of a blast is based on hydrodynamic equations; GEOMIX calculates
the blast action of borehole charges by using a velocity field, which is determined based on
their potential.
To determine the velocity potential at the charge-rock mass boundary, the time integral is
calculated for the dependence that relates the maximum pressure of the blasting products in
an explosive cavity with the velocities of detonation, a longitudinal wave in the rock mass and
density of explosives and rocks. The pressure in an explosive cavity is calculated on the basis
of time dependence, which relates the density and velocity of detonation of explosives, the
geometry of the charge and the stemming. The critical value of the rock mass displacement
velocity was adopted as a criterion for the rock mass damage.
To implement the 3D design schemes, the authors use a method of forming a regular grid
area, for each cell of which the potential is calculated and the area of damage and break line
are assessed. At the stage of dispersion of detached rocks along a ballistic trajectory and the
formation of a shotpile, the exchange of materials between the individual cells of the grid
area is monitored [3].