Sandvik MD Bolt and In-situ Dynamic Testing of Ground Support Bradley Darlington Ground Support Engineer Sandvik

Transcription

1 Sandvik MD Bolt and In-situ Dynamic Testing of Ground Support Bradley Darlington Ground Support Engineer Sandvik 1

2 Emergency Exit Protective Equipment Emergency Number Alarm Assembly Point Safety First Our EHS vision is to achieve Zero Harm to our people, to the environment we work in, to our customers and our suppliers 2 Sandvik Mining

3 Business Areas Sandvik Group Sandvik Mining Sandvik Machining Solutions Sandvik Materials Technology Sandvik Construction Sandvik Venture Equipment, tools, service and technical solutions for exploration, excavation and processing of rock and minerals in the mining 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. The world s widest range of rock Unique customer offering drilling, rock excavation, rock within selected areas. processing, demolition and bulkmaterials handling equipment, tools, services and technical solutions for the construction industry. 3

4 Outline The Sandvik Mechanical Dynamic (MD) Bolt History design & development Bolt description, Installation and static performance In-Situ Dynamic testing History Requirements of an in-situ test rig 1 st trial concept and testing Alterations required to design Final rig design and testing Future plans 4

5 The Sandvik MD Bolt History 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 5

6 The Sandvik MD Bolt Installation/Usage 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. 6

7 The 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. 7

8 In-Situ Dynamic testing History 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. 8

9 In-Situ Dynamic testing 1 st trial concept and testing Sandvik claws to couple load plate to bolt Plate to transfer load to bolt 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). Chain assembly (2.15m drop height) KCGM (Kalgoorlie Consolidated gold mine) testing 3 bolt tested, with total of 6 drops Input energy estimated at 15kJ. 890kg Mass (mill balls and shot-crete) Hybrid test rig 9

10 In-Situ Dynamic testing Final rig design 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. 10

11 In-Situ Dynamic testing Testing and results 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. 11

12 In-Situ Dynamic testing Test results summary Energy Displacement Performance Energy (kj) 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) Displacement (mm) 12

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14 In-Situ Dynamic testing Future plans 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. 14

15 Questions 15