№82-3
Numerical simulation of sand and foam stemming for improved rock fragmentation in gold-bearing quartzites
N. Zuievska1, https://orcid.org/0000-0002-1716-1447
V. Berezdetskyi1,https://orcid.org/0000-0002-9364-8273
E. Shukurlu1 https://orcid.org/0009-0004-1007-975X
1National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Kyiv, Ukraine
Coll.res.pap.nat.min.univ. 2025, 82:29-43
Full text (PDF)
https://doi.org/10.33271/crpnmu/82.029
ABSTRACT
The purpose. To quantitatively assess how the stemming material influences energy confinement and rock fragmentation efficiency in open-pit blasting of gold-bearing quartzites by comparing conventional sand with a compressible foam stemming, using high-fidelity numerical simulation methods.
Methods. A coupled Eulerian–Lagrangian scheme in ANSYS Explicit Dynamics was employed: ANFO detonation and gaseous products were modelled in an Eulerian domain; the quartzite mass and stemming were modelled in a Lagrangian domain. Quartzite behavior was represented with an RHT-type strength and damage model; sand with a granular Drucker–Prager/compaction EOS formulation; foam with a Crushable Foam model capturing pore collapse and volumetric hardening. Identical borehole geometry (Ø110 mm, 5 m depth; 3.3 m charge, 1.7 m stemming), impedance boundaries, and frictional contact were used. Simulations ran for 15 ms.
The results. Foam stemming exhibited slightly lower peak cavity pressure than sand but sustained higher pressure over time, delayed ejection, and produced wider, more uniform stress fields with greater lateral impulse transfer. Sand showed sharper peaks, faster pressure decay, and earlier ejection, concentrating effects along the borehole axis.
Originality. The scientific novelty of the study lies in improving the methodology for analyzing the influence of stemming material on the spatial stress distribution and fragmentation indicators. The proposed methodology makes it possible to assess how the stemming material affects energy confinement in the borehole and to enhance the efficiency of rock fragmentation in open-pit blasting operations.The relationships describing the change in detonation-product pressure over time for a blasthole charge were determined for various stemming materials.
Practical implementation. Results indicate that crushable foam stemming can improve fragmentation uniformity, reduce oversize, and potentially lower specific explosive consumption in hard, anisotropic quartzites. Recommended steps include parametric tuning of foam density/crush strength, mesh-convergence checks, and targeted field trials (pressure gauges, F-curves, sieve analyses) to validate gains and refine design guidelines for stemming length and material selection.
Keywords: stemming; ANFO,quartzite, foam stemming,sand stemming, ANSYS Explicit Dynamics, Eulerian–Lagrangian, RHT model, blast efficiency, pressure–time history, fragmentation.
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