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By Tom Olsen, Tom Ohrling, Peter Taggart, Chris Martin

"North American Palladium commissioned the new concentrator at the Lac des Iles mine in the summer of 2001. The 15,000 tonnes per day mill replaced the existing 2,400 tonnes per day facility, as part of a major mine expansion.At Lac des Iles, the grain size distribution of the platinum group minerals (PGM) is bi-modal. Roughly two-thirds of the PGM are relatively coarse-grained, and often associated with fast floating copper and nickel sulphides. The remainder is ultra-fine, and locked in silicates, which poses a special challenge to the metallurgist. The previous mill typically recovered just the fast-floating mineralisation, but to achieve target recoveries, the new mill has to recover a substantial amount of the ultra-fine PGM. The metallurgical challenges associated with the recovery of fine-grained PGM in the talcous Lac des Iles ores, are described.The paper describes the approach used in circuit optimisation, and how metallurgical and operational optimisation raised palladium recoveries by more than 6% in six months, by tuning the circuit to recover some of the ultra-fine PGM mineralisation.BACKGROUNDThe Lac des Iles mine, owned and operated by North American Palladium Limited, is located about 115 kilometres north of Thunder Bay, Ontario. The mine originally opened in December 1993, and prior to 2001 included a mill capable of handling 2,400 tonnes per day of ore delivered from the nearby Roby pit.Following an intensive exploration programme conducted in 1999, and a detailed feasibility study, conducted in 2000, North American Palladium initiated a mine expansion project, the objective being to expand milling throughput from 2,400 tonnes per day to 15,000 tonnes per day. This required construction of an entirely new mill, which was commissioned in May 2001."

Jan 1, 2003

By Philip Weaver

The MIDAS project is funded by the European Commission (DG Research) and began on the 1st November 2013. The project will investigate the environmental impact of deep-sea mineral and energy extraction: specifically, polymetallic sulphides, manganese nodules, cobalt-rich ferromanganese crusts and the potential mining of rare earth elements. As deep-sea mining becomes ever closer, and the International Seabed Authority begins to develop its regulatory framework for exploitation of deep-sea minerals, MIDAS is well timed to provide fundamental scientific information. The MIDAS partnership represents a unique combination of scientists, industry, social scientists, legal experts, nongovernmental organisations and small and medium enterprises. MIDAS is carrying out research into the nature and scales of the potential impacts of mining including 1) physical disturbance of the seabed by mining, the creation of mine tailings; 2) the potential effects of particle-laden plumes in the water column, and 3) the possible toxic chemicals that might be released by the mining process. Key biological unknowns, such as connectivity between populations, impacts of the loss of biological diversity on ecosystem functioning, and how quickly the ecosystems will recover will all be addressed. The plan is to use this information to aid development of recommendations for best practice in the mining industry. A key component is the involvement of industry within the project and through stakeholder engagements to find feasible solutions. The project will work closely with European and international regulatory organisations to take these recommendations forward into legislation. A major element of MIDAS will be to develop methods and technologies for 1) preparing baseline assessments of biodiversity, and 2) monitoring activities remotely in the deep sea during and after exploitation, including ecosystem recovery. To carry out this work MIDAS is conducting a number of research cruises to examine the above issues at potential sites for exploitation of SMS and nodule deposits. This talk will present some of the recent findings of the project.

Sep 1, 2014

By G. Onal, E. Gock, H. Dincer

"During the conventional chromite dissolution process; chromite ore concentrates were ground to at least <90 µm using the ball mill and after adding Na2CO3 and leaning material (instead of CaCO3 also residues from the leaching process) at a ratio of e.g. 1:0.75:1.2, depending on the specific formulation, follows the digestion e.g. in a rotary kiln, heated in countercurrent. The reaction time is 3 to 8 h. The calcine is comminuted and leached with water or a thin chromate solution. Depending on the type of ore used, the yield is 75-85 %. The disadvantage of the above-described process is that it is impossible, using current technology, to achieve a complete digestion of the chromite ores and that the chromium-containing residues have to be disposed of as special waste, involving a large financial effort.The subject of this study was the investigation of the effect of vibratory milling on chromite dissolution. The impact stress in the vibratory mill causes the mechanical activation of chromite, which is characterised by lattice defects. The degree of mechanical activation can be quantified by measuring the relative X-ray diffraction intensities at the parent lattice planes of chromite. Each relative X-ray diffraction ratio correlates with a certain degree of digestion. As opposed to vibratory milling, a complete digestion of chromite using a ball mill is impossible, even at extremely long grinding times.In this investigation a chromite concentrate from Pulpinar/Kayseri with content of 44 % Cr2O3 and the Eccentric Vibratory Mill was used. In order to verify the effect of the vibrating grinding on chromite dissolution, reaction kinetic investigations on digestion and leaching were carried out."

Jan 1, 2003

By J M. Galvin, B J. McKinnon

Lightning Ridge, Australia, is the largest opal producing area in the world. Most opal is mined from shallow underground mines by individuals or small partnerships with the industry having been protected from large-scale development to date. The safety performance of opal mining has lagged both general mining industry standards and community expectations. The application of geotechnical analysis to the opal fields has the potential to considerably reduce injuries and fatalities. With consideration of the local culture, preliminary geotechnical analysis has been applied to some current methods of work utilised at Lightning Ridge. Practical solutions have been advocated and are presented in this paper. Improvements to safety generated by these practical solutions indicate that further geotechnical research at Lightning Ridge is warranted and would be beneficial.

Jan 1, 2002

By Y Cai, B Hebblewhite

In this paper, the Australian thick coal seam underground mining potential is highlighted and the characteristics are investigated by analysing a thick seam database. It is clear that thick coal seam resources should be mined with a high recovery, productive, efficient as well as a safe and reliable mining method. Longwall Top-Coal Caving (LTCC) is the most recent thick coal seam mining method which has been developed and extensively used in China for the last ten years. The successful applications indicate that this method has a very high recovery and productivity rate and less development cost in comparison with any other thick coal seam mining method. One of the aims of the current study is to seek potential for the application of LTCC as a thick seam mining method in Australia. In this paper, preliminary results of investigation on Australian thickseam potential are given and results of data analysis for potential LTCC seams in Australia are described. The outcome of this study shows a great promise for the application of LTCC in Australian coal industry.

Jan 1, 2002

By William Wilkinson, Vladisla Kecojevic

Current three-dimensional (3D) computer design technology leveraged into drill and blast planning and operations is changing the way engineers and operations approach drill and blast design. Additionally, Global Positioning Systems (GPS) technology that is now readily available to the civilian population is being implemented into the mining sector with a variety of new products specifically designed for drill and blast operations. The objective of this article is to discuss the steps involved with 3D Computer-Aided Design (CAD) of drilling and blasting, and the benefits such a design can provide in conjunction with GPS and drill monitoring systems.

Jan 1, 2004

By R. Zivojinovic, S. Vujic, T. Tanaskovic

The problem of determining the optimum exploitation life of machinery, namely the optimum time for machinery and equipment replacement, represents a complex and highly responsible engineering task. Taking into consideration the situation prevailing at coal pit mines in Yugoslavia, the tasks of this class are very complex and difficult. To make a decision on replacement of capital equipment and machinery, such as bucket wheel excavators within the mentioned systems, understands a management task of utmost responsibility. It requires high professional and analytical knowledge as well as the reliable arguments, based on multidisciplinary professional approach. In this paper, the authors present their views on the problem of establishing the optimum exploitation life of bucket wheel excavators, offering an algorithm, based on dynamic programming, as a solution. Keywords: Bucket wheel excavators, exploitation life of machinery, optimization, operations research, theory of replacement, dynamic programming

Jan 1, 2003

By John Babcock, Gregory Poole, Ron Hudson

In January 2007, Fultondale Alabama opened a new elementary school. Site work at the old school location included blasting activities and the old school building was scheduled for demolition. With help from Apache Construction, blasting was scheduled to be performed in close proximity to the old school building prior to the demolition. Arrangements were made to perform extensive monitoring on the old school building during the blasting activities. The monitoring plan for the project included: • Pre and post blast inspections were performed on the structure; • Conventional crack monitors were installed at 22 locations throughout the structure; • Digital displacement monitors were installed at 6 locations on the structure; and • Seismographs were used to monitor structure vibration at 6 locations and ground vibrations at 9 locations. Blasting activities were allowed to produce vibration levels well above the safe levels established by the U.S. Bureau of Mines (USBM). Vibration levels up to 7.44 in/sec were recorded with no damage noted. Permanent deformation was recorded on vibration levels of 9.68 and above. Not only did this project reinforce previous studies which indicate that concrete block walls can withstand vibration levels well above 2.0 in/sec, this study was also a good example of employing new technology to help determine if/when damage occurs on a specific structure.

Jan 1, 2009

By Venda Oliveira P. J., Correia A. A. S., Danisi C. M.

"AbstractA laboratory study has been undertaken to establish common understanding of the creep phenomenon of a Portuguese soft soil chemically stabilised with binders. In order to study the effect of different stress levels on the strength and on the creep behavior of the stabilised soil, oedometer creep tests and unconfined compressive tests were performed at different curing times. Results show that the creep stress level does not influence the unconfined compressive strength. In addition, the creep phenomenon increases the unconfined compressive strength of the treated soil. Two different secondary compression indexes were recognized from the one-dimensional compression curve which increase with an exponential trend with the creep stress level.IntroductionConstruction on soft soils requires a mandatory soil stabilization work to improve mechanical characteristics of the natural soil. Deep mixing method is a worldwide employed ground improvement method, nevertheless the creep phenomenon hasn’t been yet thoroughly analyzed. Most of the published papers have focused on the analysis of the compressibility and the strength of the soil-binder mixtures without considering the creep phenomenon. However, numerical results (Venda Oliveira et al. 2009) have shown that although settlements that occur during the creep stage (namely creep strains) are less in case of treated columns, they are still important especially due to the high loads applied to the stabilised soil. The few published studies about creep behavior of soil-binder mixtures reveal that the stabilization of an organic soil with cement induces a reduction of creep deformations, which is related to the amount of cement used and that the increase of the organic matter of the soil has a negative impact on soil stabilization, further inducing a slight increase in the creep deformations (Venda Oliveira et al. 2012).As part of the current research the effect of different stress levels on the creep behavior of a soft clayey-silt soil was studied. The binder mixture used to enhance the properties of the soil had a specific composition and quantity. Unconfined compressive strength tests (UCS) and UCS creep tests were carried out at pre-set curing times in order to analyze the creep behavior of the soil-binder mixture. In particular five different creep stress levels were studied to understand its influence on the strength and on the compressibility of the stabilised soil. In addition, considerations about the secondary consolidation index are also presented."

Jan 1, 2014

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 &#181;m) 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&#174; mechanisms in the existing copper and BSF rougher circuits, and a new flash circuit (SkimAir&#174;) 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 (&lt;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 J. A. Bakken, G. Sævarsdóttir, H. Pálsson, M. Þ. Jónsson

The role of the electric arc in the consumption of electrodes in submerged arc furnaces has long been debated. The hostile environment in the furnace does not make direct measurement feasible, so simulation has been used to evaluate the arcs contribution to the erosion. Magnetofluiddynamic (MFD) electric arc simulations and a cathode / anode sub-model developed in order to provide boundary condition to the arc model have been used for this purpose. The cathode / anode sub-model provides current distributions and cathode / anode fall voltages for the arc and temperature distribution for the electrode surface, which is paramount to the erosion rate which in turn is calculated from the Clausius Clapeyron equation and the Hertz Knudsen formula for the vapour transport. In the case of high-current industrial AC arcs, arc currents are typically ~100 kA, phase voltages ~100 V and total furnace power ~10 ? 60 MW. The results show that although enormous amounts of material is evaporated, much of it recondenses on the surface. Furthermore the results show that the arc erosion increases strongly with the arc current. If a single arc is present its contribution to erosion is close to the actual total erosion in the furnace. Results from this analysis indicate that there are possibly more than one arc present in the crater, in which case less than 40% of the total erosion would be due to the arc, the rest is chemical erosion.

Jan 1, 2007

To provide operators of large-opening mines with a ventilation planning tool that will help them develop a healthier, safer, and more efficient ventilation system in the underground workplace.

Jan 3, 2006

By J. M. Clark

(Wilkes-Barre Meeting, June, 1911.) For some years past, those interested in the development of the increasingly important mining industry of Canada, have urged the adoption by the Dominion Parliament of a federal mining-law, which would have the force and stability of statutory enactment. At present, placer-mining in the Yukon Territory, is governed by the Yukon Placer Mining Act. All other mining under federal jurisdiction is governed by &apos;Orders in Council and Ministerial Regulations. In the earlier stages of development, it is perhaps a matter of necessity that these important matters should be so dealt with; but it is now felt that the time has come when mining-rights in the extensive regions under federal control should be put on a permanent basis, -and that any changes required from time to time should be made only after full and open discussion in Parliament. A short sketch will suffice to indicate how vast and varied the interests affected really are. When the Dominion of Canada was constituted by the Imperial Statute known as the British North America Act of 1867 (which came into force by proclamation on July 1 of that year), it comprised only the present Provinces of Ontario, Quebec, Nova Scotia, and New Brunswick; but provision was made for the inclusion of Newfoundland, Prince Edward Island, British Columbia, Rupert&apos;s Land, and the North West Territories. Subsequently Rupert&apos;s Land and the North West Territories were acquired, the &apos;Crown Colonies of British Columbia and * SECRETARY&apos;S NOTE.-Mr. Clark, an eminent Canadian lawyer, and joint author of the treatise on "The Law of Mines in Canada," has been requested by the Do¬minion Government to prepare a Federal mining-law, and presents this paper, by invitation of the Council, in order to obtain, if possible, useful suggestions from members of the Institute.-R. W. R.

Apr 1, 1911

By S. Jiansheng, H. Nakayama, D. Lu, A. Wang

ABSTRACT: New techniques and methods for 3D geo-mechanical model test are presented in this paper. The new model material NIOS with high density and low cost; the so-called DPSS (Discrete Principal Stress Surface) loading concept, the loading and monitoring system for the generation of the 3D initial stress field of the model test, also the special techniques and apparatuses for modelling the excavation of caverns located deep inside the model material, are developed and introduced. By adopting those new techniques, a very large 3D geo-mechanical model test with high comparability for a newly designed underground powerhouse has been successfully fulfilled. Key Words: 3D model test, underground group caverns, excavation process modeling. ZUSAMMENFASSUNG: Neue Techniken und Methoden für 3D geomechanischen Modellversuch wurden in diesem Artikel vorgestellt. Ein neues Modellmaterial mit hocher Dichte und niedrigem Preis, ein sogenanntes DPSS (Discrete principal stress surface) Ladenkonzept, ein Laden- und Überwachungssystem für die Erzeugung des 3D primären Spannungsfelds und überdies spezielle Techniken und Maschinen für das Ausbruch der tief in dem Versuchsmodell liegenden Kaverne wurden entwickelt. Bei Anwendungen dieser neuen entwickelten Techniken wurde ein sehr großer 3D Modellversuch mit großem Maßstab für ein geplantes unterirdisches Kraftwerk erfolgreich durchgeführt. Stichworte: 3D Modellversuch, unterirdischen Gruppekaverne, Ausbruchsmodellierung Résumé: le test de modèl de Nouvelles techniques et méthodes pour la géo-mécanique 3D est figuré dans ce papier. Le nouveau modèle de matériels NIOS avec la haute densité et le coût bas; la conception proposée de chargement DPSS (Discrete Principal Stress Surface), le système de chargement et de moniteur pour la génération de champs de stress initial du test de modèle, ainsi que les techniques et appareils spéciaux pour modeler les excavations de cavernes profondément localisées dans l’intérieur du matériel de modèle, sont développés et introduits. A travers l’adoptation de ces nouveaux techniques, le test de modèle de la géo-mécanique très large 3D avec la haute comparabilité pour actualiser une nouvelle étude de la centrale électrique sous-terraine a déjà accompli avec succès. Mots de clé: test de modèle 3D, groupes de cavernes sous-terraines, processus de modèle d’excavation

Jan 1, 2003

By David A. Lipton

In 1980, the U.S. Bureau of Mines conducted a mineral survey of the 23,500 acre Garcia Mountain RARE II area (No. 5107) in the Los Padres National Forest. Bureau of Mines data indicate a low potential fur gold, silver, and mercury resources. Twenty-nine placer samples, representative of small yardages, showed small amounts of gold or other economic mineral values. Mercury deposits in faulted siliceous rocks in the Franciscan Formation occur north of the area. Similar rocks are in the southwest part of the study area, but apparently contain no mercury deposits. Geothermal and oil and gas potential is low.

Jan 1, 1982

Geological Parameters Controlling the Improvement of Manufactured Sand Using Vertical Shaft Impact Crushers Instead of Cone Crushers Natural sand is a limited resource. In Sweden the total use of natural sand and gravel is around 20&nbsp;million tonnes per year and the goal is to halve the use of this resource in the near future. Most of this natural sand is used for concrete production, so the consequence of this goal is that more and more concrete must be produced with manufactured sand. The bedrock of Sweden consists mainly of granites and gneisses, rock types mainly composed of various amounts of quartz, feldspar and mica. Manufactured sand from these materials generally contains rather flaky and elongated grains, and there are few types of granite that can be used as manufactured sand in concrete without increasing the amount of cement by eight to ten per cent. A Vertical Shaft Impact crusher (VSI) is commonly used to improve the shape of coarse aggregate particles. Research has shown that it is even possible to improve the shape in aggregate fractions less than 1&nbsp;mm for some rock types. The aim of this project was to investigate which geological parameters control the improvement of manufactured sand when using VSI-crushers instead of the traditionally used cone crusher. In order to do this eight rock types of granitic composition were investigated. The selection of rock materials for the tests was based on grain size and mica content. A 4 - 8 mm fraction of each material was used for the tests. The characterisation of the shape of the material was performed using image analysis applied on microscopic images. The results showed that the VSI-crusher had improved the shape of all materials down to 0.036 mm, except for one rock sample. According to these results granites with low mica content and relatively high content of feldspars have the best prerequisites to produce manufactured sand for concrete with suitable geometric characteristics, and if these materials are crushed with a VSI crusher they almost show the same characteristics as natural sand.

Sep 13, 2010

There is a significant amount of historical mining and exploration information available. This information is often distributed throughout a number of reports or plans, available from a variety of sources, and in many differing formats. The ability to capture paper-based historical information in a modem digital format provides mining and exploration companies with valuable information that can be used in a number of ways; for example, reassessments of exploration or mining work previously undertaken, or used in conjunction with current exploration information. &nbsp; The purpose of this paper is threefold. Firstly, to present the paper-based historical information; highlighting some of the problems encountered, solutions to those problems, and any assumptions used. Secondly, to present the historical data in digital format, and demonstrate the tools available to analyse geological and associated information, and finally, to illustrate some of the potential future applications of the information, including mining optimisation, mine design and scheduling. &nbsp; The Glenorchy scheelite/gold prospect has been used as an example. Within the overall prospect two smaller areas were selected. The Mount McIntosh and surrounding areas, focuses on exploration and surface excavation information. The Mount Judah area (State and Kelly-Taylor workings) focuses on underground mining and exploration information. &nbsp;

Jan 1, 2001

By G. Paquet, E. Godin

"Since the mid fifty's, worlwide pellet production capacity has constantly risen (Fig. 1, Ref. 1 l. There was however at that time no real incentive to decrease production costs but only to produce as many pellets as possible. State of things changed with the iron and steel market recession, starting in 1975, and is currently leading producers to improve pellet quality and to reduce fuel and power consumption.At the Port-Cartier pellet plant, the energy needed for the induration of pellets ranks first in overall operating costs. An important step was made when starting admixing coke breeze in 1980. Oil prices justified the use of coke breeze as a direct replacement in terms of dollar/ton, however, while gaining expertise in using solid fuel a significant decrease in energy consumption was observed (Fig. 2, Ref. 2).In 1985, the ""Centre de Recherches minérales"" was commissioned to undertake research work to investigate the effects of further increasing coke addition to the pellet mix. The positive results of that work led to a 1,5% coke addition plant trial during the fall of 1985. Both laboratory and industrial results are discussed in this paper."

Jan 1, 1986

By D Crequer

A Peer Review Panel for the Golden Cross Mine in the upperWaitekauri Valley, Coromandel was initiated in December 1989, before mining, as a requirement of the conditions of the Mining Licence and Water Rights. The panel&apos;s function is as a technical audit and advisory team - to provide independent technical review of design, construction, and execution of mining operations, slope remediation works, and reclamation/mine closure activities. The primary role of the panel is to act in the public interest by providing assurance to regulating authorities that the design and application of on-site mining operations accords with &apos;good industry practice&apos;. Panellists are not involved in design nor as advisers, although until 1997 when explicit terms of reference were written, the panellists were a sounding board for some operational proposals. The panel functions to ensure that best mining industry technical standards are met. The costs of the peer review process are met by the mining company. Review of mining operations includes environmental matters such as land rehabilitation and water quality. The focus of this paper is on the process of peer review for environmental management factors rather than for structural and mine engineering.

Jan 1, 1998

By M Olsen, L van den Berg

Bowen Basin coalmines suffer from hot and humid ambient conditions during the summer period. The ambient conditions combined with high VRTs, increasing depth of working and significant equipment heat loads results in heat issues underground. Coalmines operate under heat stress management plans as required by legislation with associated trigger action response plans (TARPs). Some mines also employ refrigeration as part of their heat management strategy.A recent case study was conducted on a mine producing about 4.5 Mt/a from their longwall and experiences summer surface ambient temperatures of about 23.5&#186;Cwb. The expected virgin rock temperature is 46&#186;C at 300 m depth. The mine currently introduces a modest amount of surface cooling at the portal using ‘off-the-shelf’ air conditioning units. This system does not effectively manage face temperature primarily due to positional inefficiency.Underground conditions remain hot in summer and work is typically undertaken in accordance with the Heat TARP. This has a direct impact on the productivity of crews, worker comfort and also negatively impacts the workforce morale. The mine commissioned a study to determine a refrigeration strategy aimed at maintaining underground conditions below TARP levels 90&#160;per&#160;cent of the time.The ventilation network model was calibrated against actual temperature data to simulate the heat loads including longwall, conveyor system, strata and auxiliary diesel fleet. This model was then used to determine the cooling requirements for bulk surface cooling, bulk underground cooling, surface district cooling and underground district cooling strategies.These estimates were used to undertake a total owning cost trade-off for the different strategies. The study concluded that a chilled air shaft has the lowest technical risk but the highest total owning cost due to shaft development needs. Introducing chilled water to an underground cooler via boreholes offered the lowest total owning cost and was therefore recommended.CITATION:van den Berg, L and Olsen, M, 2017. Heat load assessment and mine cooling strategies for a longwall coalmine, in Proceedings Australian Mine Vent Conference 2017, pp 231–236 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017