In this paper, a multiscale modelling and simulation of destress blasting of rock mass is presented. e proposed and novel approach combines two separate 3D solutions: the first was obtained for the small-scale problem, face(s) blasting process, and the second for the global scale problem, seismic wave propagation within very large volumes of surrounding rock mass. Both the approaches were based on explicit dynamic modelling methodology using the central difference method. In the local case, the arbitrary Lagrangian-Eulerian (ALE) procedure with the Jones-Wilkins-Lee (JWL) equation defining an explosive material was used. For this purpose, a selected volume of a rock mass comprising a blasted mining face was modelled in detail. From the numerical simulation, pressure distribution over the modelled rock was obtained, which was the basis for an initial condition for the global 3D FE model. e peak particle velocity (ppv) distribution obtained from finite element analysis was compared with experimental outcomes. A reasonable agreement between both results was achieved; therefore, the adopted multiscale modelling approach confirmed its effectiveness and that it can be successfully implemented in further engineering practice.

The article presents an assessment of the influence of aluminium granules content on selected detonation parameters of a chemically sensitised bulk emulsion explosive. The analysis covered determination of relative explosive strength using a ballistic mortar and Trauzl blocks, free field air blast tests and detonation velocity measurements. Five types of emulsion explosives with differing aluminium content were tested at loadings of 0, 1, 3, 5 and 7%.

No abstract

Abstract.One of the problems associated with the excavation of deposit in underground mines is the local disturbance in a state of unstable equilibrium results in the sudden release of energy, mainly in the form of roof falls. The scale and intensity of this type of events depends on a number of factors. To minimize the risk of instability occurrence, continuous observations of the roof strata condition are recommended. Different roof strata observation methods used in the Polish copper mines have been analysed within the framework of presented paper. In addition, selected prospective methods, which could significantly increase efficiency of rock fall prevention are presented.

Abstract:One of the main parameters describing the properties of explosives is the velocity of detonation, which can be defined as the propagation speed of the chemical reaction zone in the detonating explosive. The detonation velocity of an explosive depends on many parameters, such as the material's density or diameter and the shell of an explosive, plus the degree of crystal fragmentation, the initiation method and the content of particular components. The effectiveness of blasting work in underground mines depends primarily on the proper selection of the hole diameter, hole length, the distance between the holes and the delays of the detonators used. This article presents the results of studies investigating the influence of the diameter of a bulk emulsion explosive charge on the detonation velocity using a MicroTrap TM VOD/Data Recorder manufactured by MREL, Canada. The underground tests were developed in the "Polkowice-Sieroszowice" copper mine in Poland.