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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). Scoping Study Objectives.
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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)
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
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
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
Coal Resources and Deposit Delineation Update of UNSW thick seam database from public sources (113 mines-330 point source data)
Research Direction • 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
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
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
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
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
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
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
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
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
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
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
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
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