Janda-Galán, Á. (Álvaro),Zuriguel-Ballaz, I. (Iker), Bienzobas, J., Garcimartín-Montero, Á. (Ángel), Maza-Ozcoidi, D. (Diego Martín). ""Pipe transport in underground mining: an experimental approach"", Powders and grains 2013 : Proceedings of the 7th International Conference on Micromechanics of Granular Media, pp. 710-713.
Transport of material through pipes or channels in mines or gravel quarries seems to be a simple and economic
form of conveying blasted ore between different levels. Despite the apparent advantages of moving the material by means of
the gravity force, there exists an important problem that makes the applicability of this method more difﬁcult: the election of
the pipe diameter to prevent clogging of the stones. It was R. Kvapil in the sixties who extended the ideas of granular ﬂows in
silos to underground mining. Nevertheless, after his pioneering works there are only a few manuscripts focused on this topic,
and many questions remain unsolved. In this work, we present experimental results about the ﬂow of particles (gravel) driven
by gravity through tilted tubes. The amount of material discharged between clogs shows that the probability of clogging can
be estimated by the same procedures introduced for silos. Finally, by changing the ratio between the tube diameter and the
typical particle size, we discuss about the existence or not of a critical size beyond which clogging is not possible.