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Development Of A Pre-Driven Recovery Evaluation Program For Longwall Operations, D. Wichlacz, T. Britten, B. Beamish
Development Of A Pre-Driven Recovery Evaluation Program For Longwall Operations, D. Wichlacz, T. Britten, B. Beamish
Resource Operators Conference
Many longwall coordinators are examining the use of pre-driven recovery roadways. This method, if performed successfully can improve the overall efficiency and safety of moving longwall equipment from panel to panel. However, it is difficult to assess the feasibility of using predriven recovery unless extensive research is carried out or a consultant is used to analyse the particular situation. A number of previous case studies have been analysed to discover which parameters have the greatest influence on the success of pre-driven recovery. Floor strength, Coal Mine Roof Rating (CMRR), extraction depth, Roof Density Index (RDI), standing support and mining rate …
A New Approach For Determination Of Tunnel Supporting System Using Analytical Hierarchy Process (Ahp), K. Oraee, N. Hosseini, M. Gholinejad
A New Approach For Determination Of Tunnel Supporting System Using Analytical Hierarchy Process (Ahp), K. Oraee, N. Hosseini, M. Gholinejad
Resource Operators Conference
In underground mining, the selection of support system for mine tunnel development plays a significant role in safety and economics of operations. Traditionally, such selection is on the basis of the experience of the design engineer. Nevertheless, the validity of such selection is questionable. A new approach for selecting the optimum tunnel support system based on Analytical Hierarchy Process (AHP) is proposed. In this new approach, the selection of the tunnel support system is considered as a multi criteria decision-making problem. Firstly, by using the numerical Finite Difference Method (FDM), based on technical and stability parameters of the tunnel, different …
System Management Approach To Improvements In Longwall Development, S. Barker, M. Kizil
System Management Approach To Improvements In Longwall Development, S. Barker, M. Kizil
Resource Operators Conference
The requirement for continuous improvement in the coal industry to achieve the combination of lower costs, greater capital efficiency and higher production. Longwall panels are now being mined at a faster rate requiring a commensurate increase in development rates. Development operations that cannot deliver continuity of longwall mining result in substantial flow on costs for the entire mine – from higher unit costs, lower production and loss of reliable supplier status in the coal market. A development unit which can remain well ahead of the longwall as a result of an efficient system – machines; human resources; supply logistics and …
Coal Reservoir Parameters Regulating Gas Emissions Into And From Coal Mines, A. Saghafi
Coal Reservoir Parameters Regulating Gas Emissions Into And From Coal Mines, A. Saghafi
Resource Operators Conference
A few number of gas reservoir parameters regulate the intensity and the extent of gas emissions during and following the mining of coal. Gas content is one of the most important of these parameters. Depending on the purpose of its quantification its accurate determination could be vital to the mining activities. For instance, if this parameter is used to evaluate the outburst and its value falls near the threshold limit it needs to be accurately measured. Similarly when seam gas emissions from coal mines, is to be calculated, an accurate measurement of this parameter in a carbon constraint economy has …
Coal Bumps In An Eastern Kentucky Usa Longwall Coal Mine 1989 To 1997, J. Hoelle
Coal Bumps In An Eastern Kentucky Usa Longwall Coal Mine 1989 To 1997, J. Hoelle
Resource Operators Conference
Coal mines in southern West Virginia, south-western Virginia and eastern Kentucky have experienced coal bumps at least since 1933. Most of the bumps have occurred due to high cover, strong roof and floor strata and stress concentrations due to the mining sequence. A longwall mine in eastern Kentucky first experienced coal bumps on the tailgate side of the longwall face in 1989. The bumps continued until 1996. The bumps were the result of:
• thick overburden up to 670m.
• strong roof and floor (strata strengths up to 177 MPa UCS and elasticity modulus up to 33.1 MPa
• previous …
Critical Appraisal To Assess The Extent Of Fire In Old Abandoned Coal Mine Areas - Indian Context, N. Mohalik, R. Singh, V. Singh, D. Tripathi
Critical Appraisal To Assess The Extent Of Fire In Old Abandoned Coal Mine Areas - Indian Context, N. Mohalik, R. Singh, V. Singh, D. Tripathi
Resource Operators Conference
Mine fires in Indian coal mines have a long history of over 140 years and major causes of fire are considered to be spontaneous heating of coal. Regular thermo compositional monitoring plays an important role for assessment of fire in abandoned coal mines and therefore different fire indices assist to categorise location and extent of fire. The paper highlights different methodologies to know extent of fire in old abandoned areas and reviews different fire indices for interpretation of status of mine fires with suitable case studies.
Opportunities For Improvements In Safety And Health Management Systems For Coal Mines - An Auditor's Perspective, I. Mcdonell
Opportunities For Improvements In Safety And Health Management Systems For Coal Mines - An Auditor's Perspective, I. Mcdonell
Resource Operators Conference
Auditing of Safety and Health (or Health and safety in NSW) Management Systems (SHMS) is an integral and essential process to make sure that an operation demonstrates an understanding of legislative requirements and complies with both the written law and its intent. Auditing SHMS in both NSW and Queensland has come a long way since the implementation of updated mining safety legislation that mirrors or relies on parent Workplace Health and Safety (WHS)or Occupational and Health Safety (OHS) laws. Intrinsic in this is the application of relevant Australian Standards on SHM and Quality Management. The audits in use may not …
Dust Control On Longwall Faces By Fine Mist (Atomising) Sprays - Can They Really Work?, I. Mcdonell
Dust Control On Longwall Faces By Fine Mist (Atomising) Sprays - Can They Really Work?, I. Mcdonell
Resource Operators Conference
The ongoing efforts to suppress dust emissions from longwall face shearing and transporting operations have met with varying degrees of success. A particular of concern has been the thicker, gas drained seams where both respirable and combustible fallout dust production has not always met with successful suppression methods using water spray system. There are current programs planning to use very fine atomising sprays that give a water droplet size approaching the respirable dust particle size, and mines are waiting to see how well these systems will work. Some peripheral science such as fluid mechanics and aerodynamics are discussed to determine …
Moving The Ventilation Report Into The 21st Century, J. Rowland
Moving The Ventilation Report Into The 21st Century, J. Rowland
Resource Operators Conference
Over the last three decades there has been significant technological change in both coal mine monitoring and ventilation modelling capabilities in the underground coal industry. During this time there have been substantial changes in statutory ventilation monitoring requirements to reflect such changes in our industry’s monitoring capability. Somewhat contrastingly, there has been very little change in the mandatory regulatory requirements relating to ventilation quantity and gas contamination readings that need to be taken on a monthly basis. On top of that there has been no official mention made of any requirements to model or predict ventilation circuit changes in the …
Reducing Coal Mine Ghg Emissions Through Effective Gas Drainage And Utilisation, D. Black, N. Aziz
Reducing Coal Mine Ghg Emissions Through Effective Gas Drainage And Utilisation, D. Black, N. Aziz
Resource Operators Conference
Gas emission from Australian coal mining is estimated to account for 4-5% of the nation’s 559 million tonnes of CO2 equivalent (MtCO2-e) Greenhouse Gas (GHG) emissions. With the intense focus on global GHG management and reduction, to slow the rate of climate change, significant community and political pressure exists to reduce the rate of gas emission. In December 2007 Australia committed to join the Kyoto Protocol, which in part requires annual GHG emissions not to exceed 108% of 1990 levels by the end of the 2012 commitment period. The current Australian Federal Government is presently developing the …
Times To Ignition Analysis Of New South Wales, J. Sargeant, B. Beamish, D. Chalmers
Times To Ignition Analysis Of New South Wales, J. Sargeant, B. Beamish, D. Chalmers
Resource Operators Conference
The ‘times to ignition’ theory has had limited use in the coal industry and virtually no use within Australia. The concept was originally applied to a range of Scottish coals to assess their spontaneous combustion propensity during transport in a 3x3m shipping hold. This paper presents results from an investigation into the application of the times to ignition (tad) concept to a range of New South Wales coals using data obtained from adiabatic oven self-heating tests. There is a strong association between tad and the R70 self-heating rate of a coal. The geographical location of the coal has a dramatic …
An Assessment Of The Impact Of Stylus Metallurgy On Cerchar Abrasiveness Index, J. Stanford, P. Hagan
An Assessment Of The Impact Of Stylus Metallurgy On Cerchar Abrasiveness Index, J. Stanford, P. Hagan
Resource Operators Conference
The Cerchar test is increasingly being used as a method to assess the abrasivity of rock in drilling and machine mining applications. A study was undertaken to determine the effect of changes in the metallurgy of the steel styli that is used in the test procedure on the Cerchar Abrasiveness Index (CAI) value. The study involved testing seven different metal types heat treated to the same hardness level and one steel type at nine different hardness levels. The study found there was little change in the CAI value with different steel types however hardness of the steel styli was found …
Estimation Of Coal Pillar Strength By Finite Difference Model, K. Oraee, N. Hosseini, M. Gholinejad
Estimation Of Coal Pillar Strength By Finite Difference Model, K. Oraee, N. Hosseini, M. Gholinejad
Resource Operators Conference
Longwall mining is now predominately used in coal mines where somewhat difficult conditions exist. As in the case of all other underground mining methods, pillars are integral part of modern mine design. The process of pillar design in longwall mining entails the selection of a safety factor, which is done by estimating the magnitude of the load applied on the pillar and the load bearing capacity of such pillars. Finite difference modelling principles have been applied to a typical coal pillar design. The pillar strength is then estimated with various width/height ratios. These results have been compared with the results …
Gate Road Development In High Gas Content Coal Seams At Karaganda Basin Coal Mines, Kazakhstan, D. Baimukhametov, A. Polchin, T. Dauov, S. Ogay
Gate Road Development In High Gas Content Coal Seams At Karaganda Basin Coal Mines, Kazakhstan, D. Baimukhametov, A. Polchin, T. Dauov, S. Ogay
Resource Operators Conference
Most coal seams, currently mined in the Karaganda Coal Basin, are prone to outburst. The main thick D6 coal seam is considered as most prone to outburst risk. Trials of advance degassing from the surface have not given positive results because of low permeability. 100mm diameter inseam holes are subsequently drilled in almost all longwall blocks to facilitate preliminary degassing of the coal seams. Gas extraction quantities are however low, even the holes are placed on suction To facilitate the gas release during longwall block development, of the main seam, a method of development below the seam was used. This …
Outcomes Of The Independent Inquiry Into Impacts Of Underground Coal Mining On Natural Features In The Southern Coalfield - An Overview, B. Hebblewhite
Outcomes Of The Independent Inquiry Into Impacts Of Underground Coal Mining On Natural Features In The Southern Coalfield - An Overview, B. Hebblewhite
Resource Operators Conference
An independent panel of experts was appointed in December 2006, jointly by the NSW Minister for Planning and the Minister for Primary Industries & Energy to review the current status and future implications for underground coal mining in the Southern Coalfield of NSW, with respect to its impact on natural features, particularly emphasizing risks to water flows, water quality and ecosystems; and to provide advice on best practice in regard to assessment of subsidence impacts; avoiding or minimizing adverse impacts; and management, monitoring and remediation of subsidence and subsidence-related impacts. The Panel received extensive submissions and presentations in September, 2007 …
Prediction Of Surface Subsidence Due To Inclined Very Shallow Coal Seam Mining Using Fdm, K. Shahriar, S. Amoushahi, M. Arabzadeh
Prediction Of Surface Subsidence Due To Inclined Very Shallow Coal Seam Mining Using Fdm, K. Shahriar, S. Amoushahi, M. Arabzadeh
Resource Operators Conference
Surface subsidence as an inevitable consequence of underground mining can cause problems for the environment and surface structures. Subsidence due to mining two shallow panels from an inclined coal seam C1 of the Parvadeh (Tabas) coalfield, located in the eastern part of Iran, was predicted by finite difference method (FDM) using FLAC3D software. The predicted subsidence profiles were compared favourably with both the measured values as well as the profile functions method. Using the parametric analysis, the position of maximum subsidence area was predicted over the panel rise side, which was completely in contrast with deep coal seam …
Using Helium As A Tracer Gas To Measure Vertical Overburden Conductivity Above Extraction Panels, Y. Heritage, W. Gale
Using Helium As A Tracer Gas To Measure Vertical Overburden Conductivity Above Extraction Panels, Y. Heritage, W. Gale
Resource Operators Conference
The potential of helium injection into goaf and overburden strata as a tool to determine and measure goaf to surface connectivity is discussed. Laboratory studies investigated the flow mechanics and flow velocities of injecting helium through fractures by goaf injection technique and applied the laboratory findings to the field. From the laboratory studies, it was found that the mechanics of helium flow through fractures is by bubble flow. A relationship between gas velocity and fracture aperture was found allowing the determination of fracture conductivity through helium injection, which was comparable with previous works. Field trials of helium injection into the …
Innovative Approach To Maintaining Mine Ventilation During Fan Upgrade At Carborough Downs Mine, June 2008, O. Morgan, M. Watkinson
Innovative Approach To Maintaining Mine Ventilation During Fan Upgrade At Carborough Downs Mine, June 2008, O. Morgan, M. Watkinson
Resource Operators Conference
Carborough Downs Coal Mine was developed from a box cut using three entries, one for men and materials, one for the conveyor and one return portal. The initial drivage was conducted by drill and blast and each access was ventilated by a Flaktwoods 27 m3/s 1058 50 kW fan. The box cut fan installation was transferred from the sister mine in NSW and installed on the portal. After 18 months the shock losses in the fan to adit adaptor were severely affecting the ability to increase the number of development units operating in the mine. It was decided …
Spontaneous Combustion Management - Linking Experiment With Reality, D. Cliff
Spontaneous Combustion Management - Linking Experiment With Reality, D. Cliff
Resource Operators Conference
Despite the best efforts of researchers to try to understand spontaneous combustion it still affects many mines. Laboratory testing and modelling have been available for many years and yet they are still not able to reliably predict the propensity for a coal seam to spontaneously combust. The complexities of the spontaneous combustion process are explored by delving into the chemistry of the oxidation process. It is able to demonstrate why the testing and modelling of spontaneous combustion can be of limited accuracy. Laboratory tests and simulations are carried out under conditions cannot reflect the full complexity of the underground environment. …
Low Temperature Oxidation Of A High Volatile Bituminous Turkish Coal Effects Of Temperature And Particle Size, K. Baris, V. Didari
Low Temperature Oxidation Of A High Volatile Bituminous Turkish Coal Effects Of Temperature And Particle Size, K. Baris, V. Didari
Resource Operators Conference
Low-temperature oxidation of a high volatile bituminous Turkish coal was studied using an isothermal flow reactor technique under different experimental conditions. Coal samples were ground and sieved to three different particle sizes namely -850 μm, -425 μm and -300 μm. The samples were oxidised at 40, 60 and 90°C with an oxygen flow rate of 45 mL/min. CO2 and CO emissions were analysed using an HP 5897 Series II type gas chromatograph. Temperature was found to have a definite effect; as the temperature increased rates of formation of CO2 and CO also increased significantly. Experimental results showed that …
Assessment Of Spontaneous Heating Of Coal By Differential Scanning Calorimetric Technique - An Overview, N. Mohalik, D. Panigrahi, V. Singh, R. Singh
Assessment Of Spontaneous Heating Of Coal By Differential Scanning Calorimetric Technique - An Overview, N. Mohalik, D. Panigrahi, V. Singh, R. Singh
Resource Operators Conference
Differential Scanning Calorimetric (DSC) applications in coal sciences have expanded rapidly. Various researchers observed that some of the methods to determine spontaneous heating are time consuming, tedious and do not give reproducible results. DSC instruments are usually employed under identical experimental conditions to track the reaction type (i.e., endothermic or exothermic), to calculate kinetics and heat flow rates. Application of DSC for determination of spontaneous heating of coal and suitability in this area is described.
How We Can Help And Improve, M. Velzeboer
How We Can Help And Improve, M. Velzeboer
Resource Operators Conference
The world has changed in a matter of six months. Last year the sky was the limit, today there are many companies living from hand to mouth. Bungee jumping is a recreational activity and now senior management is forced to enjoy the ride as part of day to day business. Even the Australian mining scene is affected and we are again a “cyclical” industry. This is a worry, as the economic returns pay our wages and generate the investments necessary to maintain a safe and vigorous industry. Over time as the easier deposits are being depleted, the technical and geo-environmental …
Geotechnical Evaluation Of Roof Conditions At Crinum Mine Based On Geophysical Log Interpretation, P. Hatherly, T. Medhurst, G. Ye, D. Payne
Geotechnical Evaluation Of Roof Conditions At Crinum Mine Based On Geophysical Log Interpretation, P. Hatherly, T. Medhurst, G. Ye, D. Payne
Resource Operators Conference
At the underground coal operators conference held in 2008, Payne described the experiences of crinum mine in characterising the weak roof strata at the mine. To a large extent, primary and secondary roof support strategies are based on UCS values determined from sonic logs. Consideration is also made of lithological units that can be identified on natural gamma logs. At crinum, UCS values in the roof strata tend to fall in the range 3-30 MPa. Through ACARP funded research, a new method for evaluating geotechnical conditions known as the Geophysical Strata Rating (GSR) has been developed. The GSR is based …
Alts 2009 - A Ten Year Journey, M. Colwell, R. Frith
Alts 2009 - A Ten Year Journey, M. Colwell, R. Frith
Resource Operators Conference
This paper summarises the development and application of the ALTS (Analysis of Longwall Tailgate Serviceability) design methodology for longwall gateroad design associated with Australian collieries. The original ALTS design methodology was presented to the industry via workshops in early 1999 and since that time continued research, updating of the database and direct support from most Australian longwall operations has resulted in the ALTS 2009 software package, which also incorporates ADRS (Analysis and Design of Rib Support). In addition to the chain pillar design component, ALTS 2009 now provides design recommendations for primary and secondary roof and rib support for both …
Geotechnical Assessment Of Polymeric Materials As Skin Reinforcement In Underground Mines, Jan Nemcik, I. Porter, E. Baafi, C. Lukey
Geotechnical Assessment Of Polymeric Materials As Skin Reinforcement In Underground Mines, Jan Nemcik, I. Porter, E. Baafi, C. Lukey
Resource Operators Conference
Current advances in roof support automation require a fast and effective skin reinforcement of underground mine roadways. To satisfy these needs a strong and tough fibre reinforced polymeric alternative is emerging as a logical substitute to the old steel mesh support system. Differences between steel mesh and polymer skin behaviour are investigated. Computational models are utilised to compare these two skin support systems with a view to optimising the performance needed for effective roadway skin reinforcement. In particular, development of a strong and resistant shell that minimises movement along the fractured rock and coal surfaces found between the roof bolt …
A Simulation Model For Roadway Development To Support Longwall Mining, G. Gray, E. Baafi, I. Porter, O. Rojas
A Simulation Model For Roadway Development To Support Longwall Mining, G. Gray, E. Baafi, I. Porter, O. Rojas
Resource Operators Conference
The practice of longwall mining is potentially an efficient and cost effective means of extracting coal from underground seams. However, for production targets to be achieved not only must the longwall perform as expected but roadway development must be kept ahead of the longwall advance. The evaluation of development options is a challenging exercise due to the interactions between mining, tramming and clearance operations. In particular, the high levels of variability and uncertainty in operations make it difficult to assess how a particular configuration may perform. A simulation model RoadSIM using the ARENA modelling system has been produced to assist …
On Mining-Induced Horizontal Shear Deformations Of The Ground Surface, G. Li, R. Pâquet, R. Ramage, P. Steuart
On Mining-Induced Horizontal Shear Deformations Of The Ground Surface, G. Li, R. Pâquet, R. Ramage, P. Steuart
Resource Operators Conference
Horizontal shear deformations have not been commonly considered in subsidence engineering and risk management practices. This situation is quite different from many other engineering disciplines. This article presents the authors’ initial findings of case studies from a number of collieries across all NSW Coalfields. The objective of this article is to highlight the significance of a ground deformation mode, that is, horizontal shear, and its implications to subsidence engineering and risk management. A Shear Index is suggested to facilitate studies of mining-induced shear deformations of the ground surface.
Current Status And Future Prospects Of Mining Subsidence And Ground Control Technology In China, W. Guo, Y. Zou, Y. Liu
Current Status And Future Prospects Of Mining Subsidence And Ground Control Technology In China, W. Guo, Y. Zou, Y. Liu
Resource Operators Conference
Mining of coal alters the ground stressfields, causing strata deformation, ultimately leading to surface subsidence. For the past 40 years some significant experience on mine subsidence control technology has been acquired in China, particularly when mining under buildings, railways and water bodies, which are known as "3-bodies". Current emphasis is in the evaluation of appropriate mining methods and other correlative technologies that can control or reduce the ground surface subsidence and protect surface structures. The current status of coal mining subsidence and ground control technology in China are discussed, including partial mining, backfilling, bed separation grouting, and harmonic mining. The …
Ventilation And Gas Extraction Techniques Of High Gas Seams In Kazakhstan, D. Mukhamedzhanov, S. Baimukhametov, A. Polchin
Ventilation And Gas Extraction Techniques Of High Gas Seams In Kazakhstan, D. Mukhamedzhanov, S. Baimukhametov, A. Polchin
Resource Operators Conference
The execution of gas drainage techniques to degas the high methane content seams, and to allow their safe working, is influenced by the low permeability of the coal seams. The extraction techniques of coal degasification employed are; mining the underlying thin seam before extracting the main thicker target seam; pre-drainage of the target seam, from surface in conjunction with in-seam drainage, both using vacuum extraction and; taking a top lift of the very thick seams. A significant proportion of the liberated gas is also extracted from the goaf area. Several special techniques are employed in managing the goaf gas, including …
Gas Content Estimation Using Initial Desorption Rate, D. Black, N. Aziz, M. Jurak, R. Florentin
Gas Content Estimation Using Initial Desorption Rate, D. Black, N. Aziz, M. Jurak, R. Florentin
Resource Operators Conference
The measurement of gas content plays an important role in mine safety and mine planning for coal and gas recovery. A number of methods exist to determine gas content; direct and indirect methods. The direct method of fast desorption test is the preferred method of gas content measurement. The indirect methods are based on either empirical correlations or laboratory derived sorption isotherms. Recent research has identified two new, semi-direct methods of estimating total gas content using early stage gas desorption rate measurement. Both techniques, if adopted, can provide operators with an indication of gas content and particularly whether the content …