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By P Rubie, B Morgan, J Russell, C Stewart

The relationship between efficient liner exchange, concentrator availability and concentrator profitability is well documented. Russell Mineral Equipment’s (RME) relationship with OZ Minerals’ Prominent Hill site personnel enabled sound collaboration between the two parties. Both parties worked together to identify the sources of productivity and efficiency loss and developed solutions to reverse them.This paper chronicles the identification of production inefficiencies and the resulting removal of mill relining from the critical path through the materialisation of mill relining optimisation strategies. Furthermore, this paper outlines other recent mill relining optimisation strategies developed by RME and tested at Prominent Hill, to demonstrate and achieve further productivity, efficiency and safety improvements.CITATION:Rubie, P, Russell, J, Morgan, B and Stewart, C, 2017. Mill relining optimisation – a story of collaboration, in Proceedings MetPlant 2017, pp 335–345 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By S Morgan, A Jakowetz, S Taylor, B Weekes, S Litson, P Bourke, T L. Do

In the current tough mining environment with lower commodity prices, operators need to improve operational profitability. Optimised equipment asset management is a sustainable way to achieve this objective. The increased efficiency of installed process equipment positively contributes to the circuit performance, affecting metallurgical performance, plant availability and operating costs. Nui Phao Mining Company Limited (NPMC) operates a polymetallic mine located in Vietnam. The circuit produces four main products, tungsten, fluorspar, bismuth and copper. Tungsten is the major revenue producer. The operation experienced the following equipment inefficiencies in its copper and bulk sulfide flotation (BSF) circuits:• lower than expected metallurgical performance - the BSF rougher flotation tails contained coarse (+106 µm) sulfur minerals which affected the downstream tungsten gravity circuit. The unrecovered sulfur competed with tungsten minerals affecting both tungsten recovery and product grade. • structural integrity and safety - the flotation circuit structures experienced excessive vibration beyond the acceptable tolerance levels. The vibration was attributed to the flotation mechanism design and impeller tip speeds. • equipment reliability and wear life issues - the flotation mechanisms were being replaced every six months, with reported failures at three months. This resulted in high operational costs. A mineralogical evaluation of the ore indicated that the coarse sulfur minerals were well liberated and relatively rich in pyrrhotite and pyrite. It was predicted that these particles should be recoverable by flotation under optimum conditions. NPMC worked collaboratively with Outotec to investigate options to improve the metallurgical performance of both sulfur and tungsten. A review of the copper and BSF rougher circuit infrastructure was also undertaken and focused on reducing the structural vibration and improving mechanism wear life. Prior to the circuit upgrade, laboratory and pilot testing was conducted to validate the circuit improvements. The final solution included the installation of Outotec FloatForce® mechanisms in the existing copper and BSF rougher circuits, and a new flash circuit (SkimAir®) treating the rougher tails stream ahead of the tungsten gravity circuit. The flash circuit is unique, as typically these types of cells are installed in grinding circuits. By March 2016, all circuit upgrades were complete, however the initial metallurgical performance was below expectations. NPMC and Outotec worked together to investigate and improve performance through further equipment modifications. Since October 2016, the metallurgical performance has improved significantly. Coarse sulfur mineral recovery has improved, resulting in an overall increase in recovery of sulfur and tungsten of 4.7% and 2.7% respectively. The Outotec FloatForce mechanism has also delivered operational benefits, with a reduction in structural vibration to within acceptable levels (<4.0 mm/s) and an improvement in mechanism wear life by 150%. This paper discusses the BSF circuit upgrades and compares operational data before and after the upgrade to quantify the improvements in metallurgical performance, structural vibration and mechanism wear life. CITATION:Morgan, S, Weekes, B, Jakowetz, A, Litson, S, Taylor, S, Do, T L and Bourke, P, 2017. Nui Phao mine – flotation circuit upgrade, in Proceedings MetPlant 2017, pp 230–253 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By Roberto Vargas

"El presente Trabajo de Investigación, tiene por objeto describir la tecnología, la operación del Proceso en la Planta que implementa dicha tecnología así como los resultados obtenidos en dicho Proceso y aplicaciones de la tecnología a otros tipos de concentrados de cobre (Enargita). "

Sep 1, 2017

By Hanry Guillén

En la Compañía Minera KOLPA, se analizó el comportamiento de sus operaciones unitarias por el período Marzo - Agosto 2016, en el cual se identificaron procesos asociados a los ciclos de perforación y voladura, bajo los términos de variabilidad NO ESTABLES NI SOSTENIBLES, los mismos que ameritaban medirlos, analizarlos, mejorarlos y controlarlos a fin de adoptar decisiones que conduzcan a operar la mina en términos de calidad y excelencia.

Sep 1, 2017

By Christian Flores

El proceso que se enfrentó en Tambomayo tuvo su principal complejidad en llevar un proyecto en etapa de exploración hacia la construcción de una a unidad productiva la cual permita obtener resultados económicos y trabajar con altos estándares operacionales en el que prime la seguridad y un buen clima laboral, acompañado al hecho de que la empresa cuenta con una cultura operativa tradicional, lo que género que las principales dificultades para la toma de decisiones es que se tengan que ir derrumbando paradigmas operacionales y de esta manera ser un agente de cambio para el logro de los objetivos.

Sep 1, 2017

By Luis Valle, Fredy Zegarra, Ernesto Vizcardo

El uso de los procesos estocásticos y cadenas de Markov se ha desarrollado solo para estudios de probabilidades en la rama de las ciencias matemáticas y como una opción a las descripciones tradicionales en el campo del procesamiento de minerales, se realizó una comparación entre ambas metodologías para lo cual se cuenta previamente con varios análisis granulométrico proveniente de los molinos de Bolas industriales de la empresa Shougang Perú y pruebas granulometrías de Molienda de Sider-Perú, comparar en ambos estudios, como el probabilístico (Cadenas de Markov) y el cinético (Selección y fractura) ofrecen un buen acercamiento al resultado experimental, dando como una buena alternativa el primero por su uso del manejo estocástico.

Sep 1, 2017

By Edgardo Torres Hernández

El Proyecto Optimización de Ángulos de Taludes en Explotación de Minas es un proyecto desarrollados por E-Mining Technology (EMT), socio estratégico de Prodimin en Perú, para Codelco Chile en uno de sus yacimientos del Norte de Chile. El desarrollo de este proyecto estuvo enmarcado en el Programa de Proveedores de Clase Mundial; programa que tiene como misión desarrollar un sector de proveedores intensivo en conocimiento, mediante la generación de soluciones tecnológicas empujadas desde la demanda de la minería y desde la propuesta del sector de proveedores que puedan ser escaladas a otros sectores y mercados.

Sep 1, 2017

By Lino Arias

The main objective of this project is to review and develop a comprehensive application of Lane’s cut-off grade model to a case study, as well as to compare its principles and results compared to break-even cut-off grade model utilisation under the same conditions. The case study sets the context of the application: A conceptual study of a gold open pit mining project requires a cut-off grade analysis, which consists in develop a cut-off grade policy that maximises the net present value (NPV) using Lane’s and break-even model.

Sep 1, 2017

By Juan Kobashicawa, Bernardo Falcón

En este trabajo se explican los controles automáticos desarrollados (In-House) e implementados en el circuito de Molienda de Compañía Minera Antamina, el cual abarca Molinos SAG, de Bolas y los Hidrociclones respectivos. Los controles implementados son basados en el Control por Lógica Fuzzy y las Bandas de Bollinger; así mismo se indican los criterios en el diseño de los controladores y las variables del proceso que se han tomado para la implementación donde se controla un indicador de distancia del centro de masa de la carga respecto al centro del molino de Bolas. Asimismo, se muestra el impacto positivo logrado con la estabilización del circuito.

Sep 1, 2017

By Carol Harrison

"Diseñar, implementar y evaluar un proceso de adquisición de tierras y reasentamiento ha sido un reto para los proyectos mineros en el pais, pues es un tema fundamental para el desarrollo del proyecto y reviste al mismo tiempo una alta complejidad en contextos sociales como el nuestro. Asimismo, no existe una reglamentación clara al respecto ni una institucionalidad que permita enmarcar el proceso, que al final resulta en una negociación directa entre dos partes. La presentación profundiza en ejemplos de experiencias de reasentamiento rural, particularmente en la definición y monitoreo de indicadores."

Sep 1, 2017

By Jose Luis Sosa, Marco Surichaqui, Ramirez Marcelino

El proyecto permite obtener resultados de operación que no siempre son los esperados en cuanto a calidad y recuperación, aquí es donde destaca el programa; tiene una data que PRONOSTICA estos resultados, con el control de parámetros, corrigiendo estos resultados al valor óptimo esperado, haciendo que su empleo permita obtener en “tiempo real” excelentes resultados en cuanto a calidad y recuperación del licor lixiviado y se refleja en costos.

Sep 1, 2017

By Juan Oswaldo Alfaro, Angel C. Nuñez, Hildebrando A. Cóndor

Se ha desarrollado un software para facilitar la evaluación del proceso molienda-clasificación en plantas concentradoras. Se ha modelado en UML-Lenguaje Unificado de Modelado; los datos e información se almacenó en SQL Server; se programó en Java (Programación Orientada a Objetos). Investigación Aplicada y Cuantitativa obteniendo como resultados un Software para Circuito de Molienda-Clasificación (Directa e Integral).

Sep 1, 2017

By J C. Volkwein, A D. A Hansen, E Sarver, C Barrett

Ensuring that diesel particulate matter (DPM) levels in underground metal and non-metal mines are maintained below statutory limits is an essential requirement of mine ventilation systems. However, despite the cost of providing ventilation, air ventilation rates are usually based upon models, assumptions, or measurements integrated over long durations rather than actual need. Real-time measurement of DPM, interpreted in terms of mine activity schedules, can offer better ventilation management to keep DPM within regulated levels while controlling costs. This work presents data from three demonstration sites with in-mine applications of an environmental particulate sensor that measured black carbon (BC) as a surrogate for DPM.Aethalometers are a class of environmental monitors that measure the light absorbance of aerosol particles at several optical wavelengths. A model AE33 Aethalometer was operated in three separate mines for periods of two weeks, three months, and seven-plus months, and the data was reported in real time as a concentration of BC. Concentration of aromatic organic compounds, which can indicate other forms of combustion, was also reported. The data was used to:- measure the relative efficiency of a new scale-model DPM air scrubber- determine if ventilation could be reduced in a shotcrete loading facility without compromising air quality- evaluate diurnal and weekly DPM levels in a large-entry stone mine. Instrument data were displayed locally and stored for later downloading in all cases. In one mine, the instrument was connected to a local controller, and in another it was connected to the mine’s underground network so that DPM data was presented in real time to a display in the mine ventilation engineering office on the surface.The results showed that the air scrubber removes from 82 per cent to 95 per cent of the DPM; that DPM produced during shotcrete loading is only a minor part of overall DPM levels; and that wide variations in DPM levels exist in the limestone operation. The DPM monitor operated continuously for extended periods in these underground environments. The only maintenance required was the routine replacement of filter tape, typically on a two-week schedule. A sample diluter, which is currently being tested, could extend the intervals between filter changes. The real-time data output of the Aethalometer is appropriate for direct integration into ventilation-on-demand control systems.CITATION:Volkwein, J C, Barrett, C, Sarver, E and Hansen, A D A, 2017. Application of an environmental ‘black carbon’ particulate sensor for continuous measurement of DPM in three underground mines, in Proceedings Australian Mine Vent Conference 2017, pp 143–150 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By D Caley

During the response to the Moura No 4 disaster, use was made of the New South Wales Mines Rescue Service’s ‘Mineshield’ inertisation equipment. The equipment had to be transported from Newcastle, approximately 1400 kms, and the liquid nitrogen a similar distance. The time taken, and therefore availability of the liquid nitrogen, became a significant problem. Operational issues were also experienced during use. Typically the liquid nitrogen is converted to a gas (vaporised) before being injected into the mine. However, as the propane gas tanker used for the vapourising unit was delayed, an attempt was made to inject the liquid nitrogen directly down uncased boreholes. This proved unsuccessful.Following the Moura No 4 disaster and the Moura No 2 disaster, recommendations were made relating to having inertisation capacity for the Queensland coal mining industry. Today the Queensland industry has multiple options available for inertisation, including the high-volume GAG and smaller volume units such as boilers and membrane separation units. Although it ultimately aided re-entry into Moura No 4, most likely due to the issues associated with supply to Central Queensland, liquid nitrogen has not found favour within the Queensland industry as an inertisation tool.Coregas has commissioned an air separation plant in Mackay, improving the availability of liquid nitrogen to Central Queensland. Based on the availability of this nitrogen, recent sealing operations at Kestrel have trialled using liquid nitrogen and associated vapourising units. This paper details the practical application and findings of using liquid nitrogen during routine longwall panel sealing.CITATION:Caley, D, 2017. Using liquid nitrogen for the inertisation of goafs, in Proceedings Australian Mine Vent Conference 2017, pp 35–40 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By A Liu, T Ren

Gas explosion in underground coal workings can pose a serious threat to the safety of mine workers and the entire mine operations. Gas explosion is a very complex thermal-chain reaction in a confined underground environment. Based on combustion and explosion theory, three dimensional (3D) computational models were developed to simulate mine gas explosion flame and overpressure wave propagation in a single entry gateroad in underground coalmines. Six different explosion scenarios were modelled and compared with large scale experimental results and AutoReaGas simulations. Model validations show that the use of shear-stress transport (SST) k-? model together with eddy-dissipation model (EDM) produces good agreement with both experimental and AutoReagas simulation results. Modelling results demonstrated that the changes of temperature versus time can be divided into four stages, ie the initial condition stage, and periods of warm-up, active burning, and burnt-out. Assuming a limited volume of methane is involved in the explosion, the maximum temperature decreases as the distance increases from the explosion point, with the highest temperature reaching about 2460 K. Modelling results show that the evolution of the explosion flame shape experiences four typical stages, ie spherical flame, finger-shape flame, flame with the skirt touching the side walls (ribs) and tulip flame, which are similar to the pattern of a duct explosion. The pressure in the gateroad remains the same as the initial value before the arrival of the explosion wave and then increases rapidly to the maximum value. Modelling results from this study will be used for the design of explosion arresting devices and mine seals in underground coalmines.CITATION:Liu, A and Ren, T, 2017. Computational simulation of gas explosion and its propagation in single entry gateroad, in Proceedings Australian Mine Vent Conference 2017, pp 181–188 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By B Belle

In a predrained gassy coalmine, ventilation control plays a secondary role to the longwall (LW) goaf drainage systems to safely manage panel return gas levels. Typically, the LW specific gas emission (SGE) estimation models provide anticipated goaf gas emissions and arriving at required gas drainage capacity for various coal production scenarios. A study comparing the various LW goaf gas hole spacing patterns with weekly production rates of up to 270 kt/w of an operating mine with high SGE rates (~20 m3/t) was carried out. The goaf capture efficiency of LW panels ranged from 64 per cent to 85 per cent. For the first time, gas content of upper seam data post LW retreat were used to verify the current SGE prediction models. This study has shown that an average of 50 m goaf spacing is optimal for management of high production retreat gassy LW panels in presence of multiple upper and lower seams with gas emission zone influence reaching up to 200 m above workings. Due to the horizontal stress direction related geotechnical issues, goaf hole failures just behind the LW face is a recurring challenge resulting in significant and immediate increase in LW panel return gas levels. This paper highlights the shortcomings of current SGE prediction models for goaf gas estimation, and evolution of 50 m goaf hole spacing embedded in design process in managing the LW tailgate gas levels.CITATION:Belle, B, 2017. Optimal goaf hole spacing in high production gassy Australian longwall mines – operational experiences, in Proceedings Australian Mine Vent Conference 2017, pp 15–26 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By R S. Hamilton, S R. Grobler, M E. Greenway

The progressive development of underground mines frequently requires increased ventilation flow rates through mine shafts that were originally designed for lower rates. Where these shafts are equipped with conveyances running on rope guides, the higher air flow rates adversely affect the lateral motion of conveyances and could cause conveyances to collide with the shaft walls or with one another. Hence the safety impact of higher flow rates requires proper assessment. This can be undertaken by use of computer simulation models to predict the dynamic motion of the conveyances during hoisting. It can also be undertaken entirely by field testing, or using a combination of simulation and field testing. This paper discusses these techniques and makes cautionary remarks about setting an absolute generic maximum flow velocity for all shafts. Approaches to assess existing shafts for increased ventilation flow rates are also discussed.CITATION:Greenway, M E, Grobler, S R and Hamilton, R S, 2017. Safety impact of increased shaft ventilation on rope guided conveyances, in Proceedings Australian Mine Vent Conference 2017, pp 261–270 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By Y Xiao, C Lei, C Shu, W Wang, K Wang, J Deng

To investigate the effect on coal spontaneous combustion with high geo-temperature, an experimental apparatus was developed to measure characteristic parameters of two kinds of coal samples at different temperatures: one was 40°C (G coal sample) and the other was a rising temperature from room temperature (C coal sample). Based on the relationship between CO concentration and the temperature variation, a calculation model of the apparent activation energy of coal was established. The results indicated that the oxygen consumption rate, the generation rate of CO and CO2, and heat release intensity of G coal sample were higher than C coal sample. This trend was more and more obvious as the temperature increased. Furthermore, the apparent activation energy of G coal sample was lower than C coal sample, especially at low temperature stage, which demonstrated that the more the oxidation and exothermic reaction of G coal sample was enhanced, the less energy was required to break the barrier of oxidation reaction. Under the same condition, the speed of oxidation reaction was faster for the coal in the high geo-temperature environment, which was more liable to spontaneous combustion.CITATION:Lei, C, Deng, J, Xiao, Y, Shu, C, Wang, K and Wang, W, 2017. The effect of high geo-temperature environment on spontaneous combustion – an experimental study, in Proceedings Australian Mine Vent Conference 2017, pp 137–142 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By J R. Leeming

Mining law has developed in Great Britain (GB) over centuries, mainly in response to lessons learned after disasters and other major incidents. This has led to a culture of preventing repeat accidents, rather than predicting and controlling unsafe acts or conditions.This paper explains how, initially in response to a government drive to reduce the burden on industry, the opportunity was taken to review and reform all 48 sets of GB mining-specific law into a single document. The philosophy adopted, the procedure followed and the significant changes that resulted are explained.CITATION:Leeming, J R, 2017. The complete renewal of Great Britain’s mining laws for the 21st century, in Proceedings Australian Mine Vent Conference 2017, pp 3–8 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By M A. Tuck

The dominant heat loads in a deep underground mine are the surrounding rock mass, autocompression and machinery. In addition heat can be contributed to by other sources. Many block cave, sublevel cave operations and coalmines utilise conveyors to transport broken rock out of mine, in some cases completely, in others in combination with other forms of transport. This broken rock can be loaded onto the conveyor at virgin rock temperature and can represent a major heat input to the ventilation airflow as it is transported out of the mine. The purpose of this paper is to review established knowledge regarding heat flow, from conveyed rock to determine the main factors influencing the heat flow and to develop a methodology for predicting heat flow from caved rock. The paper concludes with suggestions for further research in the area of conveyed rock heat transfer.CITATION:Tuck, T A, 2017. Accurately estimating heat load from conveyed rock, in Proceedings Australian Mine Vent Conference 2017, pp 225–230 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017