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High Capacity Underground Coal Mining (L15)

A joint project (Scoping Study) between CSIRO Exploration & Mining and University of Queensland’s

Sustainable Minerals Institute (SMI)

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Scoping Study Objectives

Benchmark current practices and determine what is needed to achieve a high capacity underground coal mine (15Mtpa) and optimisation of existing operations

Report on strategic research directions needed to support future high capacity mining.

Identify specific, high impact research and development projects to facilitate high capacity mining.

Identify opportunities for operational, technical and postgraduate training in areas relevant to high capacity coal mining

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Process

Develop a predictive model (15Mtpa coal mine) on which comprehensive research proposals would be dependent. Incorporates LW productivity, utilisation, seam characteristics, development requirements, sensitivities and cost model.

Considerations included: 1.8 – 4.5m seam thickness; LTCC and multi-seam operation

Segregate the overall strategy into 7 sub-categories for further study, under the respective objectives

Provide separate reports addressing the requirements of the scoping study

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15Mtpa model identified key issues

Criticality of system uptime

High shearer speed/power to deliver tonnages

Support hydraulics for rapid support cycle times

Optimise cutting cycle – uni-di; bi-di; half web

Development rate increase

Improved coal clearance for minimal bottlenecks

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Coal Resources and Deposit Delineation

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Coal Resources and Deposit Delineation

Update of UNSW thick seam database from public

sources (113 mines-330 point source data)

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To create confidence that a deposit will be able to host a 15Mtpa operation requires integrated analysis of geologic data across company boundaries at the district scale, similar to that in the ACARP Supermodel 2000 project

High tonnage longwall operation will require enhanced interpretation of structure and interburden characteristics

Multi-scale modeling of fault geometries and simulation of behaviour under variable rock mass, stress and mining methods

Research Direction

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Geological and Geotechnical Assessment and Support

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Current Status

Greater propensity for stability problems in thick seams operations

Geotechnical downtime generally occurs comparatively more frequently on the face (a shift from gateroads)

Geophysical methods of rock mass characterisation are preferred but there is a lack of experienced people to interpret the information

Typically 1-2 normal faults per panel

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Research Direction

Implementation of real-time face and gate road “Smart” monitoring which includes interpretation and control measures

Determination of interaction between cutting height and operational characteristics

Interaction of seams in multi-seam operations

Enhanced fault detection and definition for mining through in-panel faults – possibly utilising microseismic technology

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Roadway Development Systems

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Current Status

Later generation, best practice mines with good conditions could attain 15Mtpa mines without major developments in mining equipment and systems

Infrastructure limitations will constrain older mines from making major improvements in mine capacity, while adverse conditions generally associated with depth pose additional productivity challenges to these mines (and to later generation mines as they mature)

Technology developments are currently underway that are likely to address a number of key process constraints in the short to medium term, thus providing the potential to improve system capability across all mines

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Specific Research Projects

Extensible (monorail mounted) face services (e.g. ventilation, power, water, compressed air, pump out)

Integrated development mining system

Extensible, self advancing coal clearance system

Alternative skin reinforcement and confinement measures

Complementary technology developments including automation and robotics, machine guidance systems, light weight materials, face pumping systems, roadway construction and consolidation

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Projected Gains

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Gas and Ventilation

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Longwall Gas Emissions Related to FaceProduction

0

3,000

6,000

9,000

12,000

15,000

18,000

21,000

0 3 6 9 12 15 18

LW Production (MTpa)

LW

Go

af g

as e

mis

sio

ns

(l/s

)

Vent gas capacityBest practice with goaf drainage

SGE 5 m3/tSGE 10 m3/t

SGE 20 m3/tSGE 35 m3/t

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Research Direction

Gas Drainage

Extensive pre-drainage of gas including optimisation of MRD gas holes for pre-drainage/deep gas drainage technology and stimulation

Coordination and cooperation with petroleum and gas developers to utilise/reduce gas reservoir

Optimise goaf inertisation strategies for operational use – including exclusion foams

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Research Direction

Spontaneous Combustion

Development of low impact inertisation systems

Heat

Development of heat extraction techniques for fixed and possibly mobile plant

Dust

Optimise coal seam water injection techniques prior to mining

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Water Management

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Current Status

Water Consumption

Highest users have the highest losses; lowest users have the lowest losses

Water Inflow

Typical inflows range from 3-5 Ml/day; some up to 15Ml/day

Water use ML/Mtpa

Water loss ML/Mtpa

Range 55 – 192 29 – 180

Average 130 90

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Strategic Research Directions

Reduction in water consumption and variability through integration of research into water usage, management and technology

Integrated approach to hydro-geology and geotechnical aspects

Underground water recycling and reuse technology

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Longwall Face Equipment and CoalTransport

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Current Status

Current equipment is capable of delivering at or about the 15Mt target

Average production from the top 5 mines based on the last 3 years was 4,647,660 tonne

The average cutting hours per year calculated from the 8 mines studied over the last 3 years was 2745 hours

The average output per hour from the longwall faces was 1693 tonne

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Current Status

Longwall faces cut for only 31% of the total time in a year

Breakdown maintenance outweighs planned maintenance by 4 to 1

The shearer, panel belt and AFC, respectively, are the largest contributors to down time totalling over 50%

Planned maintenance effort does not reflect the downtime statistics and is ad-hoc

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Downtime Breakdown

Longwall Downtime Allocations

0.0

5.0

10.0

15.0

20.0

25.0

30.0

Equipment

Perc

en

tag

e

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Research Directions

Further development and implementation of face automation

Effective analysis of monitoring data on a real time basis for maintenance purposes

Real-time maintenance prioritisation system

New sensors and systems for condition monitoring

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Licence to Operate

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Specific Research Projects

Assessment, prediction and validation of the impact of increased mining height and width on local and regional water resources and catchments

Development of realistic and achievable engineering controls for dust, noise and heat management

Assess and validate current subsidence prediction methodologies for high capacity contexts