Transcript Rock Bolting for 21st Century

Self Drilling Rock Bolt
Technology
for the Coal Industry
Advanced Solutions
Ground Support Services Pty Ltd
September 2007
SDRB Advanced Solutions
A pick & shovel is cheaper than a Longwall…..but it is not as productive
…it is all about
productivity
© 2007 GSS
Pty Ltd
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SDRB Advanced Solutions
Similarly, we don’t use pit props any more……….
In the future, ……we need to provide
a GSS
leap
forward in roadway productivity
© 2007
Pty Ltd
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Operating Costs *
Costs of Operating a Miner & Installing Bolts:
Total Cost of Operating a Continuous Miner Unit per year*
Average number of metres driven per Day
$6,640,000
100
Number of Shifts per Day
3
Average number of metres driven per shift
Total Actual Operating Hours per year
33
3,072
Operating Cost per Continuous Miner Unit per hour
$2,161
Operating Cost per Continuous Miner Unit per minute
$36.02
Average Time to Install a standard rock bolt
150 secs
Average Cost of Installing a standard rock bolt based on TIME
ONLY
$90.06
Average number of standard rock bolts installed per Continuous
Miner Unit per year
51,200
Average Cost of TIME to install standard rock bolts per
Continuous Miner Unit per year
$4,611,072
* A continuous miner unit includes all equipment to drive a roadway based on ACARP Report on Roadway Development, by Gary Gibson, 2006
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Advanced SDRB Solutions

Not just about supporting the roof

Mines need the Solutions to drive Roadways faster

Need to consider the whole Roadway

SDRBs available for many years in Europe (18 SDRBs)

Pumpable Resin SDRB

Advanced Self Drilling Bolt Technology

Conclusions
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Existing SDRBs
Furen
MAI
Alwag
CarboTech
DSI
Williams
Hilti
Romtech
Stainless
Atlas Copco
Wiborex
Ischebeck
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Pumpable Resin SDRB

Full bolt encapsulation maximises roof support

No gloving, no plastic film, no under-mixing or
over-mixing

Perfect resin mixing every time

Resin fills bearing plate & locks mesh in place

Minimises water inflow from bolt holes

Minimises bolt corrosion
full encapsulation both inside and outside bolt
visible resin at collar proves full encapsulation
© 2007 GSS Pty Ltd
resin fills bearing plate & also locks mesh in place
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SDRB load transfer capacity
Load Transfer Capacity about 2 x solid bolts
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SDRB Underground Trials
Points to Note:

Once SDRB is placed in chuck, no manual
handling

SDRB remains completely straight throughout
drilling cycle

2m hole drilled in 24 secs (83mm/sec)

The water column inside the SDRB gets
displaced by the resin

Plate gets pushed firmly up against mesh at
about 400 Nm

End of bolt is completely clean
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SDRB
SDRB Progress:

Refined the bolt design
 Improved the equipment
 Improved resin
 Planning on undertaking a large scale installation
 However – need to look at a Total Solution
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Advanced SDRB Solutions
 Not about products or systems - about
Solutions
 Need to consider the whole Roadway
 How to support intersections?



Long tendon support is often essential
But installing long tendons from the miner is
slow
Outbye cable bolting sometimes too late
 How to support 3m+ ribs?

Can only install 1.2m bolts from miner
© 2007 GSS Pty Ltd
Bolt length is
restricted by
Roadway opening
11
height
Advanced SDRB Solutions

Why can’t long tendons be installed
quickly?

Long cable bolts are slow to install
Cable
Bolt
 Drill string coupled & uncoupled
 Mostly manual handling

Rock Bolt length restricted to
roadway opening?
Coupled
Bolt
 Coupled bolts - slow
 Coupled self drilling bolts – still slow
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Advanced SDRB Solutions
Why can’t we have SDRBs that can be
installed:
 Quickly?
 Automatically?
 Be longer than the roadway opening?
 Provide immediate support?
 Provide high capacity roof support?
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Advanced SDRB Solutions
Outer Bar
Inner Bar
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Advanced SDRB Solutions
Inner Bar Unscrews
Rock Face
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Telescopic SDRB
Drill Bit digs into Rock Face
Outer Bar
Inner Bar
Inner Bar Unscrews
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Telescopic SDRB
Extension here
Drill Chuck Position Fixed
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Telescopic SDRB: Drilling or Extending
Resistive Torque (Nm)
250
200
150
100
50
0
0
5
10
15
20
25
Axial Thrust (KN)
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Telescopic SDRB
1. Place Bolt in Chuck & fix in position. Begin to rotate – Axial force increases.
1
Distance to roof
remains constant
Position Fixed
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Telescopic SDRB
2. Axial force increases - locking threads - enabling drilling
1
2
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Telescopic SDRB
3. Axial force decreases as hole drilled - unlocking threads – enabling extension
1
2
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Telescopic SDRB
4. Continued drilling & extension – operator can
see full extension of Outer Bar
1
2
3
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6. Drilling continued until hole
fully drilled
7. Resin pumped
into Bolt for 30 secs
– Outer Bar fully
encapsulated
- Nut then tensioned
- Total Cycle time
~2mins
~3.9m
5. Chuck
unlocked &
travels to roof
as drilling
progresses
5
6
7
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Telescopic SDRBs
Standard SDRB
Telescopic SDRB
1.2 to 2.4m
2.0 to 4.6m
12 tonnes/100mm
20 tonnes/100mm
38 tonnes
38 tonnes
approx 25 secs
approx 60 secs
Resin Pump Time
30 secs
30 secs
Total Installation
Time
approx 60 secs
less than 120 secs
Length
Load transfer
capacity
Tensile Strength*
Drill Time
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Telescopic SDRB Technology
60 x 2m long telescopic Rib SDRBs (blue)
215 x Standard SDRBs (yellow)
10 x 4m long telescopic Roof SDRBs (blue)
55m of Roadway
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Conclusions: Telescopic SDRB

Automatically extendable

Very fast bolt installation ~120 secs

Very high load transfer capacity above normal bolt horizon

Minimises Manual Handling

Simplicity:


No drill rods, No drive dollies, No changing drill bits, No resin cartridges
& No rotation to mix resin

No Coupling

No Plastic Rods

No Jacks

No pushing rods or cables up holes
Improved Productivity
© 2007 GSS Pty Ltd
The world’s first
automatically
extendable SDRB
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Telescopic
SDRB
– a revolution in ground support
Ground Support Services Pty Ltd
© 2007 GSS Pty Ltd
September 2007
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End
© 2007 GSS Pty Ltd
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