University of Oulu

Zong-Xian Zhang, Yang Qiao, Li Yuan Chi, De-Feng Hou, Experimental study of rock fragmentation under different stemming conditions in model blasting, International Journal of Rock Mechanics and Mining Sciences, Volume 143, 2021, 104797, ISSN 1365-1609,

Experimental study of rock fragmentation under different stemming conditions in model blasting

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Author: Zhang, Zong-Xian1; Qiao, Yang1; Chi, Li Yuan2;
Organizations: 1Oulu Mining School, University of Oulu, Oulu, 90014, Finland
2State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, 100080, China
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 16.7 MB)
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Language: English
Published: Elsevier, 2021
Publish Date: 2021-06-30


Nine blasts with cylindrical granite specimens were carried out under different stemming conditions. All rock specimens had a diameter of 240 mm and a length of 300 mm. Explosive Pentaerythritol tetranitrate (PETN) with specific charges 0.2 and 0.3 kg/m³ were used, and the blasts were carried out in a large explosion chamber. Each rock specimen was enclosed by a steel box in the chamber during blasting, without constraint or confinement to the specimen from lateral and top sides. During blasting a high-speed camera was used to film the blasting process and monitor the gas ejection. After each blast all fragments were collected, sieved and analyzed. The experimental results showed that: (1) the blasts with full sand stemming yielded better (finer) fragmentation than the blasts with partial steel stemming at a constant specific charge, and (2) gas ejection from the collars of blastholes occurred much earlier in the blasts with partial steel stemming than in the blasts with full sand stemming. Based on the experimental results, it can be concluded that it is extremely important to prevent gas ejection from the collars in order to achieve desirable rock fragmentation.

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Series: International journal of rock mechanics and mining sciences
ISSN: 1365-1609
ISSN-E: 1873-4545
ISSN-L: 1365-1609
Volume: 143
Article number: 104797
DOI: 10.1016/j.ijrmms.2021.104797
Type of Publication: A1 Journal article – refereed
Field of Science: 1171 Geosciences
218 Environmental engineering
212 Civil and construction engineering
Funding: This research was supported by K. H. Renlund Foundation in Finland. The second author is grateful to China Scholarship Council (CSC) for its support to his study.
Copyright information: © 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (