ACARP PROJECT C17004 TOUGH SKIN – A SPRAY-ON POLYMERIC REPLACEMENT FOR ROOF & RIB MESH

Faculty of EngineeringFaculty of EngineeringUniversity of WollongongUniversity of Wollongong

Roadway Development Operators’ WorkshopsMarch 2009

ACARP PROJECT C17004

TOUGH SKIN – A SPRAY-ON POLYMERIC REPLACEMENT FOR ROOF & RIB MESH

Chris Lukey, Ernest Baafi, Jan Nemcik, Ian PorterSchool of Civil, Mining & Environmental Engineering

Faculty of Engineering, University of Wollongong




ObjectivesTo 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 polymer-based alternative that can be spray-applied



Why do we need an alternative to steel mesh?

Currently steel mesh is installed manually

Automatic self-drilling bolt technology cannot go aheadefficiently while mesh installation is a manual operation

A recent survey of roadway development practices hasidentified a need for an alternative to steel mesh, theinstallation of which can be automated

Automation, along with automatic bolting, will removepersonnel from the face area and allow greater rates of roadway development



Polymer Skin PropertiesCure 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 orafter cure



Occupational Hygiene

- effect of components and product on humans

- consult an occupational hygienist with coal mine experience

- improve understanding re Section 63 approval process

Other Issues & Current Work



Approval for Underground Testing (Section 63)

Use of polymeric materials underground requires approval underSection 63Range of tests required for LOBA approval (Germany), followedby further testing at MSTC (Thornton)Can take 2-4 years to obtain approvalMost requirements are relevant to use of urethanes

Negotiations initiated with DPI to establish appropriate approvalregimeDetermination of airborne emissions during spray/cure

- Headspace test- Wind tunnel spray tests

Other Issues & Current Work



To GC-MS

Sample (2g)

8cm

Only one material is of OH&S and environmental concern

Headspace Emissions Test



Fan Unit

Air “Straightener”

Tunnel

Wind Tunnel Spray Test



Spray ChamberFilter

MonitorChamber




Concrete Pavers

Spray Gun




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




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

Future Work



Conclusions

A polymeric alternative to steel mesh offers anumber 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-basedalternative to steel mesh, that can be appliedautomatically, can be developed



Acknowledgements

University of Wollongong Research CouncilACARPAnglo Coal Australia Pty LtdAustar Coal Mine Pty LtdBHP Billiton Illawarra Coal LtdBMA Coal Operations Pty LtdGary Gibson and AssociatesGujarat NRE Pty LtdHelensburgh Coal Pty LtdOaky Creek Coal Pty LtdRio Tinto Coal Australia Pty LtdSpringvale Coal Pty LtdXstrata Coal NSW Pty Ltd

ACARP PROJECT C17004 TOUGH SKIN – A SPRAY-ON POLYMERIC REPLACEMENT FOR ROOF & RIB MESH

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