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EQUIPMENT USING SELFDRILLING BOLTS TO MINIMISE

EXPOSURE TO STRATA HAZARDSIN UNDERGROUND COAL MINING

Peter CorbettTechnical Services Manager

Centennial Angus Place

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BACKGROUND• Centennial Angus Place (3Mtpa Longwall Mine)

• History of difficult strata conditions and injuries

• Underground Coal Industry – history of fatalities and injuries from strata failure

• Projects to reduce operator exposure to hazardous strata conditions

• Issues and project results to date

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TASKS WHERE OPERATOR EXPOSURE COULD BE REDUCED

1. Roof Cavities in Roadway Development

2. Longwall Recovery Face Rib Bolting

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NORMAL UNDERGROUND ROADWAY

Normal Roadway Driven by

Continuous Miner Rectangular Section

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GEOLOGICAL ZONE ROOF CONDITIONS

“Guttering” Roof Falls Out Before It Can Be Supported

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MAJOR ROOF CAVITY FORMATION

Cavity 4m above normal roof horizon

Roof Cavity

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STRATA HAZARD TO OPERATORS

Face

Normal Roof Cavity Forms

Continuous Miner

Roof Falls Out Before Support – Hazard to

Operators

Continuous Miner

Continuous Miner

Cavity Gets Too Large to Control

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PREVIOUS CAVITY SUPPORT METHOD

Hand Held Roofbolter

Elevated Work Platform

Drill Rotation Torque

Reaction Torque Transferred

Though Bolter Handle to Operator

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STRATA SUPPORT HAZARDS

• Falling objects (coal or rock) can strike operators

• Working at heights (beyond limits of equipment) – operators can fall

• Operators struck by hand held roof or rib bolters

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MAJOR GEOLOGICAL ZONE

WolganZone

Future Longwalls

Past Longwalls

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SPILING PROCESS

~300mm

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THE SOLUTION

Spiling from the Continuous Miner:

– Ensure operators not exposed to hazardous strata conditions

– Use self drilling & self grouting bolts

– Design a custom drill rig for installation

– Integrate Spiling into development process

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CONCEPT- MINER MOUNTED SPILING RIG

Continuous Miner Cutter Head

Face

Spiling Rig

Spiling BoltRoof

CavitySpiles in Face

Subsequent Roof Level

Below Spiles

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The OneStep system.

OneStep Bolt

Dispenser

Intensifier

USE OF SELF DRILLING BOLTS

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RIG MOUNTED FOR SPILING

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INSTALLATION OF SPILES

Normal Roof Horizon

Cavity

Spiling Area

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MINING IN SPILED AREA

Back to Normal Roof Horizon

From Roof Cavity

Spiling Area

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MINING IN SPILED AREAS (2)

From4.5m High

To Normal Height

Spiled Area

Roof Profile

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BENEFITS & EFFECTS• No accidents / incidents (spiling process)

• Effectively stopped cavity propagation

• Operators not exposed to unstable roof

• Integrated part of development process

• Spiling cycle time reduced (from 6.7 to 1.2 shifts)

• Equipment Design / Supply Cost $100, 000

• Implementation September 2006

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ISSUE 2: LONGWALL RECOVERY FACE RIB BOLTING

• Required to protect operators during longwall equipment recovery

• Unable to use conventional resin anchored bolts – drill hole closure

• Sprayed products ineffective - convergence

• Split set friction bolts – installation issues

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LONGWALL RECOVERY FACE RIB

3.2mFractured coal can fall from heights and

strike operators

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HAND HELD RIB BOLTING

Hand Held Rib Borer

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3 D MODEL- SHEARER MOUNTED RIB BOLTER

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SHEARER MOUNTED LW FACE DRILL RIG

Longwall Shearer

Longwall Face Drilling Rig

Carriage / Slide Assembly

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INSTALLED LONGWALL FACE RIB BOLTS

Longwall Recovery Mesh

Face Rib Bolts

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BENEFITS / EFFECTS• No injuries

• Most effective face rib support to date

• Highly productive (100 bolts in 8hr shift)

• Implemented February 2007

• Design / Supply Cost $70, 000 (2 Rigs)

• Review meeting – several improvements

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RISK MANAGEMENT PROCESS• Project Team (Process Based)

• Consultation with Workforce Representatives

• Pre-design Meetings & Underground Visits

• Preliminary Equipment Design

• Presentation to Project Team (3D Modelling)

• Risk Assessments (FMEA / WRAC / JSA)

• SWP Preparation for Trial Operation

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RISK MANAGEMENT PROCESS• Compliance Standards of Engineering Practice

• Pre-Commissioning Trials – modifications

• Certificate of Compliance

• Operator training / assessment / authorisation

• Commissioning Process - “fine tune” SWP’s

• JSA’s during commissioning

• Review operations after use

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INNOVATIVE CONCEPTS USED FOR EQUIPMENT / PROCESS IMPROVEMENT

• Use of self drilling / self resin anchoring bolts in areas with high risk of strata failure

• Equipment designed to allow operator to drill / install support remotely from hazardous strata conditions

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SIGNIFICANCE• First operational uses of Hilti One-Step bolts

• Equipment designed to minimise operator exposure to hazardous strata conditions with major risk reduction

• Equipment / Methods transferable to other operations

• Successful partnering between industry and suppliers – further projects planned

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TRANSFERABILITY ACROSS INDUSTRY

• Other mines looking at these new equipment / processes

– Continuous Miner Mounted Spiling Rig– Shearer Mounted Longwall Face Drilling Rig

• These items have Copyright by Rambor

• Application of Hilti One-Step bolts