ACARP PROJECT C17004
TOUGH SKIN – A SPRAY-ON POLYMERIC
REPLACEMENT FOR ROOF & RIB MESH
Chris Lukey, Ernest Baafi, Jan Nemcik, Ian Porter
School of Civil, Mining & Environmental Engineering
Faculty of Engineering, University of Wollongong
Roadway Development Operators’ Workshops
March 2009
Roadway Development Operators’ Workshops
March 2009
Faculty of Engineering
University of Wollongong
Objectives
To develop an alternative to steel mesh that:
* Provides an effective skin confinement measure
equivalent or superior to that of steel mesh
* Requires minimal human intervention in its installation
* Removes personnel from the immediate face area
* Enables higher underground roadway development rates
to be achieved
* Is safe to use
* Is cost effective
The focus of our work is the development of a polymerbased alternative that can be spray-applied
Roadway Development Operators’ Workshops
March 2009
Faculty of Engineering
University of Wollongong
Why do we need an alternative to steel mesh?
Currently steel mesh is installed manually
Automatic self-drilling bolt technology cannot go ahead
efficiently while mesh installation is a manual operation
A recent survey of roadway development practices has
identified a need for an alternative to steel mesh, the
installation of which can be automated
Automation, along with automatic bolting, will remove
personnel from the face area and allow greater rates
of roadway development
Roadway Development Operators’ Workshops
March 2009
Faculty of Engineering
University of Wollongong
Polymer Skin Properties
Cure Characteristics
- sets in a few seconds and can be bolted through
Mechanical Properties
- tough with some flexibility
- adheres to strata to provide additional reinforcement
Flow Characteristics
- spray viscosity, followed by rapid viscosity increase
(cure) immediately after application to avoid slumping
Fire Retardant & Anti-static
Environmental & OH&S Issues
- no toxic or irritant emissions before, during or
after cure
Roadway Development Operators’ Workshops
March 2009
Faculty of Engineering
University of Wollongong
Other Issues & Current Work
Occupational Hygiene
- effect of components and product on humans
- consult an occupational hygienist with coal mine experience
- improve understanding re Section 63 approval process
Roadway Development Operators’ Workshops
March 2009
Faculty of Engineering
University of Wollongong
Other Issues & Current Work
Approval for Underground Testing (Section 63)
Use of polymeric materials underground requires approval unde
Section 63
Range of tests required for LOBA approval (Germany), followed
by further testing at MSTC (Thornton)
Can take 2-4 years to obtain approval
Most requirements are relevant to use of urethanes
Negotiations initiated with DPI to establish appropriate approval
regime
Determination of airborne emissions during spray/cure
- Headspace test
- Wind tunnel spray tests
Roadway Development Operators’ Workshops
March 2009
Faculty of Engineering
University of Wollongong
Headspace Emissions Test
To GC-MS
8cm
Sample (2g)
Only one material is of OH&S and environmental concern
Roadway Development Operators’ Workshops
March 2009
Faculty of Engineering
University of Wollongong
Wind Tunnel Spray Test
Air “Straightener”
Fan Unit
Tunnel
Roadway Development Operators’ Workshops
March 2009
Faculty of Engineering
University of Wollongong
Wind Tunnel Spray Test
Monitor
Chamber
Filter
Spray Chamber
Roadway Development Operators’ Workshops
March 2009
Faculty of Engineering
University of Wollongong
Wind Tunnel Spray Test
Concrete Pavers
Spray Gun
Roadway Development Operators’ Workshops
March 2009
Faculty of Engineering
University of Wollongong
Wind Tunnel Spray Test
First test conducted with minimum permissible air velocity (0.5m/s)
to simulate worst-case mine ventilation scenario
Air samples collected:
* During spray
* Immediately after spray
* After one further hour whilst maintaining ventilation in the tunnel
Successfully sprayed and cured a developmental formulation
No reinforcement included
Minimal odour detected
Quantification of off-gases
Roadway Development Operators’ Workshops
March 2009
Faculty of Engineering
University of Wollongong
Future Work
Lab-scale testing
- odour test (wind tunnel)
- combustion products
- temperature increase of sprayed material when curing
- methods for introduction of reinforcement
- product optimisation
Laboratory pilot-scale tests
- application of fully-optioned product
- proposed to build test gallery at UoW
- includes pilot testing of automation options
Final pilot-scale tests conducted at Londonderry
- spray using reinforcement
- mechanical properties
- emission data
Roadway Development Operators’ Workshops
March 2009
Faculty of Engineering
University of Wollongong
Conclusions
A polymeric alternative to steel mesh offers a
number of advantages:
* Can be coupled with automatic self-drilling bolts
* Entire roadway support process can be automated
* Manual handling of mesh can be eliminated
* Roadway development rates can be increased
We have demonstrated that a viable polymer-based
alternative to steel mesh, that can be applied
automatically, can be developed
Roadway Development Operators’ Workshops
March 2009
Faculty of Engineering
University of Wollongong
Acknowledgements
University of Wollongong Research Council
ACARP
Anglo Coal Australia Pty Ltd
Austar Coal Mine Pty Ltd
BHP Billiton Illawarra Coal Ltd
BMA Coal Operations Pty Ltd
Gary Gibson and Associates
Gujarat NRE Pty Ltd
Helensburgh Coal Pty Ltd
Oaky Creek Coal Pty Ltd
Rio Tinto Coal Australia Pty Ltd
Springvale Coal Pty Ltd
Xstrata Coal NSW Pty Ltd
Roadway Development Operators’ Workshops
March 2009
Faculty of Engineering
University of Wollongong