Digital Commons Network^™

Trends In Mining Education, Recruitment And Employee Development, Ray Tolhurst

Resource Operators Conference

The Australian National Skills Council has identified the mining industry as having one of the most acute skills shortages amongst all industries. (National Skills Council, 2023), Data gathered from surveys of the 10 Australian universities delivering mining programmes, (National Mining Engineering Academics Network E-Newsletter, 2023), and from the National Centre for Vocational Education Research, (NCVER, 2023), has been analysed to demonstrate trends that are occurring. Whilst the analysis has been for the entire mining sector, where appropriate, an emphasis on the coal industry has been highlighted.

The major trends show a stagnant to decline in the traditional Bachelor of Mining …

Coal Strength Measurement By Stereo Digital Image Correlation, Xiaohan Yang, Mehdi Serati, Paul Buddery

Resource Operators Conference

Correct estimation of coal mechanical properties, including Young's modulus and Poisson's ratio, play a crucial role in on-site coal mining design and numerical simulations of coal behaviour. Traditionally, these parameters are determined through laboratory testing of cylindrical samples using strain gauges. However, such methods have limitations due to the potential errors from strain gauge misplacement, localised measurements at the gauge placement area, and difficulty in preparing a standard-size sample from coal. To overcome these challenges, this paper assesses the applicability of the Digital Image Correlation (DIC) technique on Brazilian-sized disc-shape coal specimens. Several benchmark tests were first conducted under uniaxial …

Spontaneous Combustion Hazard Likelihood Assessment Of Low Reactivity Coals, Jan Theiler, Basil Beamish

Resource Operators Conference

Risk assessment has two components, hazard likelihood and consequence. There appears to be some confusion in terminology within the coal mining industry that equates the term propensity with likelihood when assessing spontaneous combustion risk. Spontaneous combustion propensity is determined using a number of index parameters that are obtained using specific test procedures. However, the propensity ratings obtained are based on a relative scale and in isolation they are effectively only a measure of the coal intrinsic reactivity. For some indices (R70 and SHT) this reactivity measure relates to the low temperature end of the self-heating spectrum and in others (CPT) …

Investigating The Axial And Shear Performance Of Fiberglass Rock Bolts, Shima Entezam, Behshad Jodeiri Shokri, Hadi Nourizadeh, Peter Gregor, Alireza Entezam, Ali Mirzaghorbanali, Kevin Mcdougall, Waru Karunasena, Naj Aziz

Resource Operators Conference

This paper primarily evaluates the axial and shear performance of fully grouted fibreglass- reinforced polymer (FRP) rock bolting systems. For this purpose, a FRP rock bolt with a diameter of 20 mm was selected for examination. To evaluate the axial performance, several samples with a double- embedment length of 150 mm and an exposed length of 200 mm were cast using an 80 MPa cementitious grout and cured for 28 days. Pull-out tests were then conducted at a controlled rate of 1 mm/min with a 1000 KN MTS apparatus to determine the pull-out performance of the FRP bolts. Furthermore, a …

Finite Element Simulation Of Fully Grouted Rock Bolts Behaviour Across Varied Bore Hole Diameters, Behshad Jodeiri Shokri, Ali Mirzaghorbanali, Waru Karunasena, Kevin Mcdougall, Naj Aziz, Shima Entezam, Hadi Nourizadeh, Amin Motallebiyan, Alireza Entezam

Resource Operators Conference

This paper introduces a finite element (FE) method to simulate the impact of confinement conditions on the axial load-bearing capacity of fully grouted rock bolts. The study utilises a combination of experimental and numerical modelling techniques. For this purpose, two different sizes of steel sleeves were used as confinements with a diameter of 23 mm and 50 mm. The samples were cured after embedding and grouting the bolt for 28 days. Subsequently, pull-out tests were conducted to assess the axial load-bearing capacity of the samples. The results showed a direct correlation between increased confinement diameter and higher values of ultimate …

Adsorption Behavior Of Silica Nanofluid On Coal And Its Injection Enhancement Mechanism, Tiancheng Zhang, Quanle Zou, Zhongwei Chen

Resource Operators Conference

Coal seam water injection has proven effective in mitigating coal and gas outburst disasters in mines. However, its drawbacks, including the poor wettability of coal seams and the susceptibility to filtration loss of injected water, have led to low construction efficiency and uneven control outcomes. In this study, we propose a novel approach to address these issues by utilizing a water-based silica nanofluid to alter surface wettability. The four-stage deposition process of nanoparticles on the coal surface is identified, and the time-varying behaviour of modified coal wettability is revealed under the influence of key parameters, such as particle concentration. These …

Active Ultrasonic Monitoring Of Damage Progression In Coal Under Uniaxial Compression, Jiangwan He, Mehdi Serati, Martin Veidt, Alessandro Carcione

Resource Operators Conference

Coal burst is a sudden and violent failure resulting from the formation and accumulation of microcracks caused by high overburden stresses, posing a significant safety risk to underground mining operations. Conventional stress-strain methods, often used for fracture assessment, are prone to subjectivity and errors, especially in highly fractured coal samples. This study investigates the feasibility of utilising ultrasonic through-transmission techniques as an alternative approach to determine the crack damage stress thresholds for coal. During uniaxial compression, changes in ultrasonic wave amplitude, wave velocity, dominant frequency, and Root-Mean-Square Voltage (VRMS) are actively monitored using 1 MHz and 100 kHz excitation frequencies. …

A Niche Application Of Permanent Co2 Disposal From Coal-Fired Power Stations Via Mineralisation In Proximal Mafic And Ultramafic Deposits, Muhannad Al Kalbani, Mehdi Serati, Harald Hoffman, Thierry Bore

Resource Operators Conference

Australia's coal-fired power stations accounted for approximately 23% of the country's total Green House Gas (GHG) emissions from all power stations in the 2021-2022 period. These emissions encompass both Scope 1 and Scope 2 categories. Such a significant contribution has led to continuous criticism of the coal industry within Australia, as the global energy landscape shifts towards a broader range of low to zero-emission energy sources. This transition calls for the coal industry to explore innovative methods to capture and remove Green House Gas emissions, particularly CO₂, which is a major contributor to global warming. Current CO_{2 …}

What Future For The Mining Engineer, Society And Humankind?, Brian G. D Smart

Resource Operators Conference

Society and ultimately humankind are entirely dependent on the outputs of the mining industry for their existence and development. The mining industry cannot, however, operate without the input of properly educated mining engineers. Unfortunately, in a significant number of countries the mining industry is not seen as an attractive employer and hence the number of student applications and mining schools are in decline. The paper examines the position in the UK, where only one of previously seven mining schools survives - Camborne School of Mines.

The ”system” that controls the provision of mining engineering education in UK Universities is described, …

Characterisation Of Roof Behaviour And Primary Support Response At Ulan West Mine, Terry Medhurst, Adrian Moodie, Brian Vorster

Resource Operators Conference

This paper outlines a study of roof behaviour at Ulan West Mine which addressed factors such as the influence of mining direction and sequence on roadway stability; stress impacts during intersection formation; variation in strata conditions, choice and timing of support installation in relation to strata management triggers. Three-dimensional modelling of itersection formation was undertaken that included quantifying the impact of grouting cables for different roof types. This was augmented with 2D modelling to investigate immediate roof beam performance, particularly in relation to heights of softening and potential strata response.

Further analysis was then undertaken using an analytical beam-column model …

Analysis Of Apparent Resistivity Change During Waterproof Coal Pillar Seepage Based On Finite Element Method, Qiang Liu, Liming Qiu, Dazhao Song, Zhenlei Li, Yi Zhu, Jintao Dang

Resource Operators Conference

Waterproof coal pillar infiltration water makes water conduction channel formed in the coal pillar and may lead to the occurrence of underground water accident. The monitoring of seepage water in waterproof coal pillars is a necessary means to prevent and control the destabilization of waterproof coal pillars. This paper establishes a coupled model of seepage field and resistivity of water-bearing coal column, analyzes the changes of seepage field and pore water pressure of water- bearing coal column, and combines the inversion technique of direct current method to determine the apparent resistivity changes of seepage process. The following main conclusions are …

Optimising Adjacent Goaf Drainage Operations By Utilising Automated Control Logic At Kestrel South Mine, William Sloan, Michael Desira, Tim Huston

Resource Operators Conference

Seal leakage contributes significantly to methane emissions during longwall mining, occurring when a sealed goaf pressurises with coal seam gas from overlying seams within the sealed goaf subsidence zone, which then leaks into the tailgate roadway. This paper aimed to minimise methane seal leakage in an active tailgate by optimising sealed goaf drainage and its influence on nitrogen inertisation. Optimisation occurred through developing an automated control system that varied sealed goaf drainage quantity in response to variable barometric pressures. The methodology analysed the adjacent goaf drainage operations at Kestrel South Mine, utilising goaf wells on the tailgate side of the …

A Case Study Of Coal Seam Uis Hydraulic Fracturing Practices And Resultant Mining Conditions, Richard Campbell, Kyle Mclennan, Andrew Seccombe, Kerri Smit, Brent Creevey

Resource Operators Conference

Carborough Downs Coal Mine experienced isolated areas of reserves with abnormally low seam permeability which had not been successfully drained to below the gas outburst threshold by SIS and UIS methods typically applied by the operation.

As a result, the mine successfully implemented trials of UIS based inseam hydraulic fracturing to increase gas drainage rates. Successful reduction of the in situ gas content from near virgin levels of around 14m³/t to below the required threshold of 7.42m³/t allowed development of gate roads, an installation face and subsequent longwall extraction.

The intensity of UIS drilling and hydraulic …

Development Of A Protodyakonov Test From Gas Drainage Core Samples And Empirical Correlation To Observed Outburst Risk, Jessica Juric, Russell Thomas

Resource Operators Conference

Given the recent interest within the Australian coal industry around the use of Protodyakonov Index as means to assess outburst probability, a method to test core samples retrieved by underground inseam drilling was developed, and results compared to development experience in an Australian mine that has had outbursts during remote mining above outburst threshold. The dataset included a large number of core samples and lump samples from outbursts that occurred under remote mining at an Australian underground coal mine. This provides a unique data set from Australian conditions, the authors are unaware of other datasets including both a large number …

Measurements Of The Height Of Fracturing And Height Of Depressurisation Above A Longwall Panel, Ben Blacka, Adrian Rippon, Nick Le Baut

Resource Operators Conference

This paper presents the findings of a program of work to determine the height of mining induced fracturing and the height of groundwater depressurisation above a longwall panel. The program of work utilised two fully cored boreholes drilled from surface at Tahmoor Colliery, located southwest of Sydney in the Southern Coalfields in New South Wales. The boreholes were drilled adjacent to and over a subcritical longwall panel, one before and one after extraction of the longwall panel.

Field measurements of the geotechnical and hydrological ground conditions in the pre and post mining boreholes were compared. Three geomechanical zones were determined …

Xcell Cyclops: The Experience Of Measuring Convergence In Hard Rock Mines, Osvaldo Vallati, Bradley Darlington, Peter Young

Resource Operators Conference

This paper presents the xCell Convergence monitoring system that has recently been developed and used to measure convergence in metalliferous hard rock mines. The system is simple to use, easily installed, economical and provides a real-time continuous flow of convergence data directly to the cloud-based application.

The xCell Cyclops is the measuring sensor, it utilises laser technology to measure distance from the mounted location to the opposite side of the tunnel. The xCell Cyclops is directly installed onto an MD, MDX and Kinloc bolts or, using an adapter, any standard threaded bolt. The device is battery powered, wireless and with …

Component-Level Material Characterization Of Timber Chocks, Mohsen Dehghanipoodeh, Hossein Masoumi, Javad Hashemi

Resource Operators Conference

To stabilize underground coal mining operations, timber chocks play a vital role by providing resistance against roof and floor convergences, which can help to maintain safety and productivity at a high level. This type of standing support system offers numerous benefits, including cost-effectiveness, rapid installation and minimal service requirements. This paper presents an investigation into the material characterization of timber chocks at the component level. To achieve this goal, several experimental tests were conducted to determine the mechanical properties of hardwood timbers. These properties include compressive and bending strengths as well as modulus of elasticity. Additionally, the study examines the …

Variations In The Mechanical Properties Of Coal Related To Structural Deformation And Burst Events, James Anderson, Ismet Canbulat, Serkan Saydam

Resource Operators Conference

This paper summarises the research conducted to provide a new means of measuring the burst propensity of coal. Burst events in underground coal mines are commonly associated with structurally disturbed coal. As part of this study, a series of samples were collected from burst and non-burst sites for UCS testing to identify the changing burst propensity of different seams in proximity to geological structures.

Applying the three critical factors of the burst triangle, coal, energy, and isotropic mass, identifies the controlling factor of burst events to be isotropic mass. Isotropic mass influences the confinement of the coal mass and energy …

Experimental Study On Stress-Seepage Characteristics Of Fractured Shale From The Longmaxi Formation In China, Lei Zhang, Xiaochuan Yuan, Naj Aziz, Yongcheng Liu

Resource Operators Conference

Effective shale gas production requires modification of gas reservoirs. By constructing a multi-level fracture network spatial structure, the porosity and connectivity of the rock formations are improved, promoting reservoir permeability and increasing the production of shale gas wells. This study conducted seepage tests on fractured rock mass samples from the Longmaxi Formation, China, under various stress conditions using nitrogen gas. The pore fluid pressure, effective stress and confining pressure effects on volume permeability were analyzed, and stress-seepage relationships for fractured shale samples were obtained. The permeability of fractured rock samples under study at fixed confining pressure for nitrogen gas followed …

A Simulation Model To Access The Impact Of Underground Coal Mine Logistics Strain On An Operation, David Walker, Ernest Baafi, Senevi Kiridena

Resource Operators Conference

A novel approach has been developed to strategically identify logistical bottlenecks and the impacts that mine planning parameters might have on these at any point in time throughout life of a mine plan. An XPAC-based model is employed at a macroscopic level to understand trends and shifts in logistical strain for a timeframe up to the entire life of mine. However, on a day-to-day basis the XPAC-based model cannot, at a very detailed level, provide information to analyse if logistical strain can be alleviated through finer adjustments. The finer adjustments that can be identified and rectified, can be determined using …

The Influence Of Drilling Technology On The Qualitative Assessment Of The Rock Mass, Petr Waclawik, Radovan Kukutsch, Martin Vavro

Resource Operators Conference

A comparison of rock quality designation (RQD) parameters obtained from drill core analysis and the RQD determined from the walls of boreholes are presented in various type of rock mass. The borehole-walls imaging were carried out on the basis of optical and acoustic televiewer records evaluation. A comparison of the RQD calculated from the drill core and the RQD from the optical and acoustic televiewer records shows that the RQD values from the drill core are on average 30% lower. Significant differences were recorded particularly near the surface, or near mine excavations. The RQD parameter for rocks of the borehole …

Application Of Waste Glass Powder In Cemenitious Grouts, Alireza Entezam, Hadi Nourizadeh, Ali Mirzaghorbanali, Polly Burey, Tristan Shelley, Naj Aziz

Resource Operators Conference

Every year, a significant volume of waste glass, amounting to millions of tons, is generated globally. Once glass becomes waste, it is commonly disposed of in landfills, posing sustainability challenges as it does not decompose in the natural environment. Glass is primarily composed of silica. Utilizing milled (ground) waste glass, as a partial substitute for cementitious grouts, represents a crucial stride in the advancement of sustainable infrastructure systems that are environmentally friendly, energy-efficient, and cost-effective. When waste glass is ground into micro-sized particles, it is anticipated to engage in pozzolanic reactions with cement hydrates. This interaction is poised to enhance …

Compressive Tests Of An Improved Non-Metallic Pumpable Roof Support, Kent Mctyer

Resource Operators Conference

Pumpable Crib Bags (PCBs) are an effective standing support solution commonly used in the tailgates of underground longwall mines. PCBs continue to gain favour due to technical benefits such as high stiffness, and operational benefits such as reductions in labour and machinery requirements. Yet little improvement in design has occurred since their introduction in the late 1990s. The lack of PCB development has meant that the traditional post-peak trait of PCBs has remained. Typically, PCBs offer high stiffness and peak load, but suffer from a post peak strain softening behaviour. Recently, a new PCB design was developed with the aim …

Investigating The Potential Of Mine-Based Geothermal Energy Systems, Pabasara Wanniarachchige

Resource Operators Conference

Geothermal energy, the thermal energy harnessed from Earth's crust, is a renewable, low-carbon resource. Underground mines offer a cost-effective means for geothermal utilisation due to elevated geothermal gradients and accessible void spaces. Mine-based geothermal systems can leverage mine ventilation exhaust, mine water, and rock strata; however, mine water based geothermal recovery systems stand out as the dominant mode, particularly in abandoned and flooded mines, where heat pumps can be further utilised to extract thermal energy efficiently. This paper delves into diverse aspects of mine water-based geothermal systems, including different configurations, critical parameters, and critical factors of implementing the technology, including …

Coal Burst Phenomenon In Underground Coal Mining: Triggering Mechanisms And Causative Factors, Adel Mottahedi, Naj Aziz, Alex Remennikov, Mohammad Ataei

Resource Operators Conference

A coal burst is one of the catastrophic phenomena may occurring in underground coal mines. It definitely put at risk both human and equipment. Obviously, coal bursts are triggered by various mechanisms and there are many factors affecting coal burst triggering. Besides, the influence or importance levels of these causing factors are not constant. Therefore, the identification of coal burst triggering mechanisms, their causing factors, and the importance levels of these factors are vital for engineers to take more appropriate mitigating measures to minimize the adverse consequences of coal bursts. Hence, in this study, coal burst causing factors are investigated …

Influence Of Water Saturation Duration On The Mechanical Properties And Toughness Index Of Australian Coal, Itmam Abedin, Ting Ren

Resource Operators Conference

The coal seam water infusion technique is recognized as a successful method for mitigating the occurrence of rock and coal bursts. As coal burst is a process of energy accumulation and release, the mechanical properties of coal, such as Uniaxial Compressive Strength (UCS), toughness, and elastic modulus, play a significant role. The water infusion method is already an industry-practiced technique to control the accumulation and release of energy by reducing compressive strength and elasticity. However, its effectiveness is potentially specific to each case and subject to the properties of the rock and coal. Several parameters influence the efficacy of this …

Aspects Of Testing Tendon Supports For Strength, Effective Installation, And Performance In Different Ground Formation, Adel Mottahedi, Naj Aziz, Ali Mirzaghorbanali, Alex Remennikov, Sina Anzanpour

Resource Operators Conference

Different methods and techniques are reported in testing several types of tendons including solid rebars and cable bolts to evaluate their strength and performances in various rock formations. Most reported studies are laboratory-based, enhanced occasionally with numerical studies. Moreover, some tests are also carried out in situ to verify test results obtained from laboratory studies. The laboratory strength studies involved both push and pull testing, single and double shear testing of solid rebar, fiberglass rods, and cable bolts using different grout types installed in composite mediums of varied strength. Several challenges are faced when undertaking these various tests. These challenges …

Finite Element Modelling Of Fully Encapsulated Cable Bolts In Laboratory Large Scale Pull Out Test, Ashkan Rastegarmanesh, Ali Mirzaghorbanali, Kevin Mcdougall, Naj Aziz, Sina Anzanpour, Hadi Nourizadeh

Resource Operators Conference

Modelling cable bolts in numerical software is a challenging task. Cables are made from multiple strands wound together and when loaded, they tend to act in a way more complex manner than rock bolts. This study used laboratory data from large scale pull out testing of fully encapsulated cable bolts using cementitious grout. A finite element method was adopted and a series of engineering simplifications and assumptions were made to increase the efficiency of the model. The results were able to illustrate a better capability in modelling the bulbed cables compared to the plain cables. Also, the sensitivity analysis proposed …

Pcd Bit Developments To Improve Bolt Load Transfer And Decrease Drilling Times, Warren Roach

Resource Operators Conference

The development of the Poly-Crystalline Diamond (PCD) bits for use in underground coal mines has historically utilised the technologies and improvements developed for the oil and gas industry.

For smaller bit diameters (27 to 29 mm) utilised in development panels that have hard and/or abrasive strata in the primary bolted horizon, the technology improvements of the PCD cutters themselves can be applied from the oil and gas industry. However, the design of the drill bit body needed input from an alternative influence to drive improvements in penetration rates, increased bolt load transfer and decreased loading on the drilling equipment.

This …

Determination Of Fuel Consumption Of Dump Trucks Depending On Mining And Technical Conditions, Borya Orkhontuul, Bayaraa Byambadagva, Baldan Purevtogtokh, Udanbor Uyansanaa, Damba Badamgarav

Resource Operators Conference

In 2017, the MICROMINE PITRAM system began to be used in open-pit mining by Erdenet Mining Corporation which allows researchers and production engineers as well as technicians to obtain highly accurate information on the use and technical condition of mining machines and self- propelled equipment in a fairly short time, providing the opportunity to develop scientifically based technical and technological solutions for the company. Due to the change in the mining and technical conditions of the Erdenet ore mine along with an increase in the depth of the mine, the average transportation distance increased to 7-10 km and the increase …