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Bradley DarlingtonGround Support Engineer
Sandvik
Sandvik MD Bolt and In-situ Dynamic Testing of Ground Support
Sandvik MD Bolt and In-situ dynamic testing of ground support1
Sandvik Mining
Safety FirstProtective Equipment
AssemblyPoint
EmergencyExit
EmergencyNumber
Alarm
Our EHS vision is to achieve Zero Harm to ourpeople, to the environment we work in, to our
customers and our suppliers
2 Sandvik MD Bolt and In-situ dynamic testing of ground support
3
Business AreasSandvikGroup
SandvikMachiningSolutions
SandvikMaterialsTechnology
SandvikConstruction
SandvikMining
SandvikVenture
Equipment, tools, service
and technical solutions for
exploration, excavation and
processing of rock and minerals
in the mining industry.
The world’s widest range of rock
drilling, rock excavation, rock
processing, demolition and bulk-
materials handling equipment, tools,
services and technical solutions for the
construction industry.
Holds a clear global leadership
by offering productivity
enhancing products and
solutions for advanced industrial
metal cutting.
Industry-leading provider
of high value-added products in
advanced metallic materials for
selected niches in the most
demanding industries.
Unique customer offering
within selected areas.
• The Sandvik Mechanical Dynamic (MD) Bolt• History – design & development
• Bolt description, Installation and static performance
Sandvik MD Bolt and In-situ dynamic testing of ground support4
Outline
• In-Situ Dynamic testing• History
• Requirements of an in-situ test rig
• 1st trial concept and testing
• Alterations required to design
• Final rig design and testing
• Future plans
• Design• Single pass Mechanical bolt
• Suitable for seismic conditions
• Comprises of Friction shell and point anchor at toe end
• Development• Developed for ground conditions where standard friction bolts are not sufficient and resin/grouted
bolts are difficult to install.
• Developed in partnership with Fosterville gold mine in Bendigo, Victoria, Australia
Sandvik MD Bolt and In-situ dynamic testing of ground support5
HistoryThe Sandvik MD Bolt
• Installation• Installed with Jumbo in Australian mines.
• Installed with same procedure as a traditional friction bolt, with additional rotation process.
• Usage• Major usage at 6 sites across Australia.
• 10 additional site in trial phase.
Sandvik MD Bolt and In-situ dynamic testing of ground support6
Installation/UsageThe Sandvik MD Bolt
• Testing• Standard QC testing involves in-situ quasi-static pull testing.
• Non-destructive testing to 15t.
• Typically 1% of installed bolts.
• Site feedback• Simple 1 pass bolt.
• Operator acceptance.
Sandvik MD Bolt and In-situ dynamic testing of ground support7
The Sandvik MD Bolt
• Lab testing• Test laboratories include WASM (Australia), CANMET (Canada)
• Performed under laboratory conditions.
• Difficult to correlate to underground rock conditions.
• Loading is purely axial.
• Current “in-situ” testing (underground)• Installation QC test has been used at 1 site in Australia, but did not allow
measuring of load, and was very basic.
• Proved effective for QC testing.
Sandvik MD Bolt and In-situ dynamic testing of ground support8
HistoryIn-Situ Dynamic testing
• Development• Initial concept developed in partnership with Mt Charlotte mine
(KCGM)
• Hybrid of existing test rig and Sandvik design
• All design completed, and verified through the use of Finite Element Analysis (FEA).
• KCGM (Kalgoorlie Consolidated gold mine) testing• 3 bolt tested, with total of 6 drops
• Input energy estimated at 15kJ.
Sandvik MD Bolt and In-situ dynamic testing of ground support9
1st trial concept and testingIn-Situ Dynamic testing
Plate to transfer load to bolt
Chain assembly (2.15m drop height)
890kg Mass (mill balls and shot-crete)
Sandvik claws to couple load plate to bolt
Hybrid test rig
• Modifications from the trial design• Release mechanism requires review.
• Load transfer element should not be chains.
• Energy application method needs to be adjustable, up to 30kJ.
• Load/energy applied to bolt must be measured.
• Displacement can be measured more effectively.
• Time to assemble (both on new bolt or on same bolt) must be reduced.
• Method to remotely release and to record load and displacement.
Sandvik MD Bolt and In-situ dynamic testing of ground support10
Final rig designIn-Situ Dynamic testing
Sandvik MD Bolt and In-situ dynamic testing of ground support11
Testing and resultsIn-Situ Dynamic testing
•First site trial of final rig • Conducted at Mine A in Tasmania, Australia.
• 5 Bolts tested with a total of 6 drops
• The impact energy was varied between 17-33kJ, resulting in a range of displacements.
• Test method still requires development in regard to testing regime.
•Second site trial of final rig• Conducted at Mine B in Western Australia.
• 7 bolts tested with a total of 12 drops.
• The impact energy ranged between 12-26kJ, resulting in a range of displacements.
Sandvik MD Bolt and In-situ dynamic testing of ground support12
Test results summaryIn-Situ Dynamic testing
0
5
10
15
20
25
30
35
0 100 200 300 400 500 600 700
Ener
gy (k
J)
Displacement (mm)
Energy Displacement Performance
Trial rig site
MD Bolt Mine A (Oct 2013)
MD Bolt Mine B (Dec 2013)
Inflatable bolt (WASM data)
Split tube (WASM data)
Target results (25kJ, 300mm)
Sandvik MD Bolt and In-situ dynamic testing of ground support14
Future plansIn-Situ Dynamic testing
• Continue to test at new sites with different rock conditions.
• Continue to develop the test rig and process.
• Expand testing outside of Australia.
• Extend the tests to other dynamic bolts.
• Increase the awareness of the advantage of testing ground support elements in-situ.