Effects of Subdrilling on Broken Zone Beneath Bench Floor at Kevitsa Open Pit Mine: A Case Study.
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| Title: | Effects of Subdrilling on Broken Zone Beneath Bench Floor at Kevitsa Open Pit Mine: A Case Study. |
|---|---|
| Authors: | Chi, Li Yuan1 (AUTHOR) Liyuan.chi@oulu.fi, Zhang, Zong-Xian1 (AUTHOR) Zongxian.zhang@oulu.fi, Ylitalo, Riika M.2,3 (AUTHOR) Riika.ylitalo@geovisor.fi, Bergström, Pekka2 (AUTHOR) Pekka.bergstrom@boliden.com, Haugen, Sunniva4 (AUTHOR) Sunniva.Haugen@boliden.com |
| Source: | Rock Mechanics & Rock Engineering. Nov2025, Vol. 58 Issue 11, p12029-12047. 19p. |
| Subjects: | Boring & drilling (Earth & rocks), Explosives analysis, Excavation (Civil engineering), Shearing force, Rock mechanics, Rock deformation, Quarries & quarrying, Computer simulation |
| Abstract: | The effect of subdrilling length on the broken zone beneath the bench floor was studied at the Kevitsa open pit mine. Five full-scale blast tests were conducted in the mine where each blast was divided into a test area and a reference area. In all the test areas, a 1.0 m subdrilling length was used, while in all the reference areas, a 1.5 m subdrilling length was employed. Two diameters of blastholes (165 mm and 229 mm) and two detonator initiation methods (the middle-detonator position and double-detonator position) were involved. The rock fragment size from both test and reference areas was measured during the muckpile extraction process. After removing muckpiles, the coordinate data of the bench floor were captured using handheld GPS devices. The broken zone beneath the bench floor was detected while drilling holes on the bench floor for lower level blasts. The test results indicated that implementing the 1.0 m subdrilling effectively reduced the median broken zone by 18.9%-55.9%, compared to the conventional 1.5 m subdrilling. Meanwhile, the short subdrilling length had minimal impact on other blasting outcomes, including the post-blast elevation of bench floor and rock fragmentation. In addition, numerical simulation was conducted using the three-dimensional bench model with a single blasthole. The simulation results revealed that the maximum shear stress concentration zone beneath the bench floor for the 1.0 m subdrilling was located 0.5 m higher than that for the 1.5 m subdrilling, consistent with the broken zone measured from field tests. Highlights: Effects of subdrilling length on broken zone beneath bench floor were investigated experimentally and numerically. Broken zone was reduced by 18.9%–55.9% in 1.0 m subdrilling, compared to 1.5 m subdrilling. Reduction of subdrilling has minimal impact on bench floor elevation and rock fragmentation. Maximum shear stress concentration zones from numerical simulations were consistent with field tests. [ABSTRACT FROM AUTHOR] |
| Copyright of Rock Mechanics & Rock Engineering is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 189531286 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Effects of Subdrilling on Broken Zone Beneath Bench Floor at Kevitsa Open Pit Mine: A Case Study. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Chi%2C+Li+Yuan%22">Chi, Li Yuan</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> Liyuan.chi@oulu.fi</i><br /><searchLink fieldCode="AR" term="%22Zhang%2C+Zong-Xian%22">Zhang, Zong-Xian</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> Zongxian.zhang@oulu.fi</i><br /><searchLink fieldCode="AR" term="%22Ylitalo%2C+Riika+M%2E%22">Ylitalo, Riika M.</searchLink><relatesTo>2,3</relatesTo> (AUTHOR)<i> Riika.ylitalo@geovisor.fi</i><br /><searchLink fieldCode="AR" term="%22Bergström%2C+Pekka%22">Bergström, Pekka</searchLink><relatesTo>2</relatesTo> (AUTHOR)<i> Pekka.bergstrom@boliden.com</i><br /><searchLink fieldCode="AR" term="%22Haugen%2C+Sunniva%22">Haugen, Sunniva</searchLink><relatesTo>4</relatesTo> (AUTHOR)<i> Sunniva.Haugen@boliden.com</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Rock+Mechanics+%26+Rock+Engineering%22">Rock Mechanics & Rock Engineering</searchLink>. Nov2025, Vol. 58 Issue 11, p12029-12047. 19p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Boring+%26+drilling+%28Earth+%26+rocks%29%22">Boring & drilling (Earth & rocks)</searchLink><br /><searchLink fieldCode="DE" term="%22Explosives+analysis%22">Explosives analysis</searchLink><br /><searchLink fieldCode="DE" term="%22Excavation+%28Civil+engineering%29%22">Excavation (Civil engineering)</searchLink><br /><searchLink fieldCode="DE" term="%22Shearing+force%22">Shearing force</searchLink><br /><searchLink fieldCode="DE" term="%22Rock+mechanics%22">Rock mechanics</searchLink><br /><searchLink fieldCode="DE" term="%22Rock+deformation%22">Rock deformation</searchLink><br /><searchLink fieldCode="DE" term="%22Quarries+%26+quarrying%22">Quarries & quarrying</searchLink><br /><searchLink fieldCode="DE" term="%22Computer+simulation%22">Computer simulation</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: The effect of subdrilling length on the broken zone beneath the bench floor was studied at the Kevitsa open pit mine. Five full-scale blast tests were conducted in the mine where each blast was divided into a test area and a reference area. In all the test areas, a 1.0 m subdrilling length was used, while in all the reference areas, a 1.5 m subdrilling length was employed. Two diameters of blastholes (165 mm and 229 mm) and two detonator initiation methods (the middle-detonator position and double-detonator position) were involved. The rock fragment size from both test and reference areas was measured during the muckpile extraction process. After removing muckpiles, the coordinate data of the bench floor were captured using handheld GPS devices. The broken zone beneath the bench floor was detected while drilling holes on the bench floor for lower level blasts. The test results indicated that implementing the 1.0 m subdrilling effectively reduced the median broken zone by 18.9%-55.9%, compared to the conventional 1.5 m subdrilling. Meanwhile, the short subdrilling length had minimal impact on other blasting outcomes, including the post-blast elevation of bench floor and rock fragmentation. In addition, numerical simulation was conducted using the three-dimensional bench model with a single blasthole. The simulation results revealed that the maximum shear stress concentration zone beneath the bench floor for the 1.0 m subdrilling was located 0.5 m higher than that for the 1.5 m subdrilling, consistent with the broken zone measured from field tests. Highlights: Effects of subdrilling length on broken zone beneath bench floor were investigated experimentally and numerically. Broken zone was reduced by 18.9%–55.9% in 1.0 m subdrilling, compared to 1.5 m subdrilling. Reduction of subdrilling has minimal impact on bench floor elevation and rock fragmentation. Maximum shear stress concentration zones from numerical simulations were consistent with field tests. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Rock Mechanics & Rock Engineering is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1007/s00603-025-04683-6 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 19 StartPage: 12029 Subjects: – SubjectFull: Boring & drilling (Earth & rocks) Type: general – SubjectFull: Explosives analysis Type: general – SubjectFull: Excavation (Civil engineering) Type: general – SubjectFull: Shearing force Type: general – SubjectFull: Rock mechanics Type: general – SubjectFull: Rock deformation Type: general – SubjectFull: Quarries & quarrying Type: general – SubjectFull: Computer simulation Type: general Titles: – TitleFull: Effects of Subdrilling on Broken Zone Beneath Bench Floor at Kevitsa Open Pit Mine: A Case Study. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Chi, Li Yuan – PersonEntity: Name: NameFull: Zhang, Zong-Xian – PersonEntity: Name: NameFull: Ylitalo, Riika M. – PersonEntity: Name: NameFull: Bergström, Pekka – PersonEntity: Name: NameFull: Haugen, Sunniva IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 11 Text: Nov2025 Type: published Y: 2025 Identifiers: – Type: issn-print Value: 07232632 Numbering: – Type: volume Value: 58 – Type: issue Value: 11 Titles: – TitleFull: Rock Mechanics & Rock Engineering Type: main |
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