"Improvements in the Bolting Cycle Using Conventional Installation Methods" John Naylor – Queensland Technical Manager, Jennmar Harold Hinton – Queensland Mine Services Supervisor, Jennmar Peter Craig – Mining Engineer, Jennmar Andy Sykes – Commercial Manager, J-Lok Resins Australia BBUGS November 2011

 ACARP Project C11028, June 2007 (GSS Pty Ltd) Quote: “ The consumable cost of a standard rock bolt is typically about $10 - $12 each. This $10-$12 bolt consumable cost equates to about 15 to 18 seconds of installation cost. That is, if bolts can be installed only 15 seconds faster than current practices, then it will pay for the consumable cost of a standard rock bolt” After ACARP June 2007 BBUGS November 2011

Canbulat & Munoz, June 11

 Aim: Eliminate the “hold time” of resin bolt installation to take 15 – 25 seconds off the cycle time.  Method: Take the Anglo “Spin-to-Stall” concept used in South Africa for the past decade and design a system to suit Australia’s M24 bolts, mm diameter holes and most critical the various continuous miner mounted bolting rigs. BBUGS November 2011

 John Naylor & Peter Craig visited Anglo’s Greenside Mine, Rocbolt Resins plant and a roof bolt manufacturing plant. Information gathered; ◦ Spin-to-stall has been in use for over a decade ◦ Approx. 2.5 million spin-to-stall installations are performed every year using “Rocbolt Resins” capsules ◦ Over 95% of mines using STS have Fletcher bolters ◦ Quality of installation is visually very high with pre-tension and tail lengths consistent ◦ Standard system is 20mm diameter (M22) 1.8m long bolt, 900mm long x 24mm capsule, 25mm hole dry drilled ◦ Bolt pre-tension is set to 5 tonne BBUGS November 2011

 Aims were to determine the following; ◦ Resin speed setting required ◦ Nut break-out torque required ◦ Effects on bond strength between “spin-and-hold” and “spin-to-stall”, and with different pre-tension values BBUGS November 2011

 The most common problem reported from South Africa was the reliability on accuracy of the shear-pins  Over the last year Jennmar had introduced a diverse range of roll-pin nuts to specific break-out torque ranges  The indication from South Africa was that the starting point should be Jennmar’s most common “green” pin, which proved correct in the installation trials and pull tests

BBUGS November mm bond length selected due to the strong roof which could reach > bolt yield on 300mm JX Profile Bolt

BBUGS November 2011 J-Lok STSA-C Resin : Spin-to-Stall Installation Technique J-Lok STSA-C resin: Current Spin-and-Hold standard installation technique Mix Times Spin-and-hold: Spin s, Hold >20s Total spin and hold > 30 s Spin-to-stall: Spin when roll pin broke 15s Total spin to stall s

BBUGS November 2011 : 3-4 t pre-tension : 8 t pre-tension :11–12 t pre-tension Slight 2 – 3 s hold as nut moved out of dolly Appeared to be ‘just’ pulling out

BBUGS November 2011 Test # Installation Technique Stall Torque (N.m) Bond Strength* (tonnes per 200mm encap) Average Bond Strength (tonnes per 200mm encap) 1 Spin-and- hold Not applicable as waited for cure Spin-to-Stall (questionable variation due to pull out?)

BBUGS November The J-Lok STSA-C speed resin capsule formulation sets a starting points for further trials and achieved correct spin- to-stall installation technique 2. Mixing the resin through the gel phase up to the nut break- out did not reduce bond strength, it actually increased: I.Bond strength was increased >90% when stall torque was N.m (3 - 4 tonnes pre-tension) II.Bond strength was increased >40% when stall torque was 270 N.m (8 tonnes pre-tension). 3. Attempting stall torque above the current industry standard 320 N.m minimum output of drill motors (>10t pre-tension) may reduce the bond strength and even result in failed installations by spin-to-stall MOST IMPORTANTLY -> BOND STRENGTH RESULTS INDICATE THAT THE PROJECT CAN BE CONTINUED

BBUGS November Fine tuning of the resin speed is required on various types of CM mounted bolting rigs 2. Drill motor rotation variation with thrust requires detailed investigation with bolting rig OEM’s. The ability to maintain full thrust pressure during rotation up through the resin will be necessary for successful spin-to-stall. This was highlighted by operators having to manually work with the controls to enable successful installation 3. Further STSA pull tests in various strata using the split bolt method are required to build a comparison against current industry standard support 4. Defining the relationship between “stall tension” and bond strength may be critical during the pull test data analysis

BBUGS November 2011  AAMC – Anglo Grasstree Mine ◦ Ismet Canbulat – AAMC Principal Geotechnical Engineer ◦ Jason Emery – Grasstree Geotechnical Co-ordinator ◦ James Mason – Grasstree Geotechnical Engineer  J-Lok Australia Pty Ltd ◦ Richard Hahn – CEO & Production Manager ◦ Lynda Laidler – Quality Manager  Rocbolt Resins (Pty) Ltd (South Africa) ◦ Andrè Odendaal ◦ Frik Blom ◦ Max Hahn

BBUGS November 2011 Contact Addresses John Naylor – Queensland Technical Manager, Jennmar Harold Hinton – Queensland Mine Services Supervisor, Jennmar Peter Craig – Mining Engineer, Jennmar Andy Sykes – Commercial Manager, J-Lok