Paper contribution

Experimental Analysis of Flake Formation Under Roadheader’s Pick Impact

Diego José Guerrero-Miguel; M, Inmaculada Álvarez-Fernández; M. Belén Prendes-Gero; Celestino González-Nicieza

Proceedings
EUROCK 2026
Pages
385-390
Submitted
28 January 2026
Accepted
15 June 2026
Published
12 August 2026

Summary

Abstract

The removal of rock material is a fundamental requirement to successful execution of most mining and civil engineering projects. Depending on the properties of the material to be excavated, roadheaders are frequently used as primary excavation tools. These machines employ an array of picks to fragment the rock, producing small portions -flakes. Consequently, the efficiency of this process significantly influences the economic revenue and the viability of such projects. To gain a deeper understanding into the physical mechanisms underlying flake formation, the phenomenon was replicated at a laboratory mid-scale to examine the influence of most relevant involved variables. Specifically, a previously designed pendulum testing apparatus was used to conduct an experimental campaign in concrete specimens subjected to dynamic impact. The experimental campaign involved variations of the impact angle and the distance from the impact point to the free edge of the specimens. The tests were recorded using a high-speed camera to reveal the strong dependency of flake formation on both the angle of impact and proximity to the free edge. Additionally, the resulting fracture surfaces were characterized using three-dimensional scanning techniques to evaluate the effective damage produced depending on the transmitted energy. For small angles and elevated distances from the free face, impacts produced minimal surface damage, mainly generating powder without flakes. Conversely, higher angles and closer proximity to the edge favored the formation of distinct flakes, which may also involve internal grain rupture. The fractured surfaces often resembled Gaussian bell shapes, suggesting a potential predictive model for flake volume and propagation based on impact parameters. Some tests exhibited multiple and sequential flake detachments, proving that pick action may be performed in different interactions rather than with a simultaneous failure in the affected area. These insights contribute to a better understanding of dynamic fragmentation in brittle and heterogeneous materials.

Contributors

Authors

  1. Diego José Guerrero-Miguel DinRock Research Group, University of Oviedo, Spain ORCID 0000-0002-9125-4860
  2. M, Inmaculada Álvarez-Fernández DinRock Research Group, University of Oviedo, Spain ORCID 0000-0002-5681-6530
  3. M. Belén Prendes-Gero DinRock Research Group, University of Oviedo, Spain ORCID 0000-0001-9125-4863
  4. Celestino González-Nicieza DinRock Research Group, University of Oviedo, Spain ORCID 0000-0002-2575-9676

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References

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