1. ACARP Roadway Development Operators Workshops - October 2011
How megabolts installed as primary support assist in safely improving development rates
ACARP Roadway Development Operators Workshops - October 2011

2. ACARP Roadway Development Operators Workshops - October 2011
Introduction
Three types of megabolts installed from continuous miner
Post grouted megastrands – MW9
Resin anchored, torque-tensioned megaflex bolts - TTX
Resin anchored, post groutable fibreglass rib bolts
ACARP Roadway Development Operators Workshops - October 2011

3. ACARP Roadway Development Operators Workshops - October 2011
MW9 Megabolt
Most commonly installed megabolt is the barrel & wedge version – MW9
Fully bulbed using spiral rib wire for max load transfer
Up to 11 m long cables installed from miner in LW installation roads
ACARP Roadway Development Operators Workshops - October 2011

4. MW9 – Nth Goonyella face road
ACARP Roadway Development Operators Workshops - October 2011

5. ACARP Roadway Development Operators Workshop 2011
MW9 advantages
42 mm hole – no reaming
Single 1,000 mm resin capsule with resin retainer
Resin pushed up hole with bolt – no conduit
Collar fittings attached after bolt installed
No bearing plate or bolt head to catch on walkway
ACARP Roadway Development Operators Workshop 2011

6. ACARP Roadway Development Operators Workshop 2011
MW9 advantages
Tension within 5 mins of installation
Tension using system hydraulics or intensifier
9 to 20 t pre-tension can be achieved depending whether system hydraulics or intensifier used
No air needed on miner
Provides immediate point anchor support of 57 t
ACARP Roadway Development Operators Workshop 2011

7. Important considerations
Bolt is point anchored until grouted
Anchor length designed to take capacity of bolt – depends on rock type at anchor horizon
Pull tests must be done to determine if anchor can take full capacity of bolt
This ungrouted bolt is loaded to tonnes
ACARP Roadway Development Operators Workshop 2011

8. ACARP Roadway Development Operators Workshop 2011
MW9 grouting
Top down grouted using grout lance – quickest grouting method
Grouting done within designated time or distance advanced – depends on conditions
Heavy conditions may require grouting within 24 hrs
Good conditions (intersections) can be left for more than a week
ACARP Roadway Development Operators Workshop 2011

9. ACARP Roadway Development Operators Workshop 2011
MW9 grouting
Grout generally reaches sufficient strength (30 to 40 MPa) within 24 hrs
Readily & easily audited
Regular auditing has greatly improved quality of installation
Grouting non-compliance now less than 5%
Good installation reduces likelihood of remedial roof support
ACARP Roadway Development Operators Workshop 2011

10. ACARP Roadway Development Operators Workshop 2011
MW9 developments
Mechanised insertion
Lobster from Conway Engineering
Being used at Angus Place
Favourable reports so far
ACARP Roadway Development Operators Workshop 2011

11. ACARP Roadway Development Operators Workshop 2011
MW9 developments
Resin grouting using Minova Carbothix
Immediate roof support
Remote pumping
Quicker grouting
ACARP Roadway Development Operators Workshop 2011

12. ACARP Roadway Development Operators Workshop 2011
Megaflex TTX
Torque-tensioned
TT bolt becoming more in demand
56 t and 48 t versions
56 t generally requires 28 mm hole
48 t a 27 mm hole
ACARP Roadway Development Operators Workshop 2011

13. ACARP Roadway Development Operators Workshops - October 2011
TTX – advantages
No exposure to high pressure tensioner hydraulics
Reduced injuries from handling tensioners
Quicker installation than hydraulically tensioned cables
Combo dolly
ACARP Roadway Development Operators Workshops - October 2011

14. Combo dolly – no changing dollies
Mixing
Inner socket engages hex drive
Tightening
Outer socket engages nut
ACARP Roadway Development Operators Workshops - October 2011

15. ACARP Roadway Development Operators Workshop 2011
TTX – advantages
Roller race between nut & washer reduces friction
Race is shrouded to keep bearing free of dirt or mud
7 t bolt tension from 320 Nm drill torque
Minimal protrusion from roof – important in low seams
Removing hex drive reduces protrusion further – as little as 115 mm
ACARP Roadway Development Operators Workshop 2011

16. ACARP Roadway Development Operators Workshop 2011
TTX – advantages
Wires are anchored in the bolt head using button heads forged on end of each wire – maintains max collar strength
B&W anchor typically reduces cable collar capacity by approx 10%
ACARP Roadway Development Operators Workshop 2011

17. ACARP Roadway Development Operators Workshop 2011
TTX – advantages
Increased load transfer from spiral wire
Groutable version being developed – will require 42 mm dia. hole
ACARP Roadway Development Operators Workshop 2011

18. Limitations of torque-tensioned cables
Reduced bolt pre-tension compared to hydraulic tensioning
Possible use of torque multipliers
Slows down installation
Failure of torque multiplier can delay production
Possible safety issues
May need modifications to head-plate of drill mast to accommodate bolt and/or dolly
Full resin encapsulation difficult for cables > 4 m
Load transfer lower than for bulbed cables
If bulbed then larger hole dia. & bigger resin capsule
ACARP Roadway Development Operators Workshop 2011

19. ACARP Roadway Development Operators Workshops - October 2011
Groutable FG rib bolt
42 t capacity
Cuttable
42-45 mm drill hole
Point anchored initially
Breakout nut
High torsion strength – stalls rib bolting rigs
17 t collar capacity
Shear strength of 14 t
SG of 1.9 to 2.1 – separates in washery
ACARP Roadway Development Operators Workshops - October 2011

20. Groutable FG rib dowel - advantages
Immediate rib support
Hollow centre - post groutable with thixotropic grout
Full encapsulation vital in heavy rib conditions
Easily audited
No secondary rib support required – maximises development rates
ACARP Roadway Development Operators Workshops - October 2011