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Glück auf! 4/2017

The application of mine ventilation technology is becoming an increasingly important topic due to the many different factors and influences at play in this area, including technical and technological developments and the tougher new requirements that have been imposed in respect of occupational health and safety protection. This issue of Mining Report Glückauf therefore examines developments in mine ventilation over the course of recent decades and discusses the current challenges and possibilities that exist in this particular field.

The development of the mineral mining industry has always been characterised by an increase in the working depth, greater complexity in underground infrastructure and the introduction of new mining methods and technologies. This created a need not only to install underground ventilation systems in general but also to provide ever more effectively controlled ventilation in line with the demand for greater volumes of fresh air supplied to the workings.

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With my best regards // Mit freundlichem Glückauf
Dipl.-Ing. Andreas-Peter Sitte
Chief Editor Mining Report Glückauf, Essen

ISSUE 04/2017

Mine Ventilation in the 21st Century – Development Towards Adaptive Ventilation Systems

Fig. 2. Ventilation lab at Clausthal University of Technology. // Bild 2. Wetterlabor an der TU Clausthal. Source/Quelle: TUC

Mine ventilation and climatization became increasingly important over the last decade. Main challenges and drivers have been the development of mining activities towards greater depths, more complex deposits with a larger areal extent, the further introduction and implementation of diesel-powered vehicles as well as stricter occupational exposure limits and rising energy costs. To meet these requirements and to keep the operation viable, new holistic ventilation concepts, methods and tools need to be developed for providing and guaranteeing sufficient fresh air for safe and efficient operations in underground mines at all times and all locations. Current approaches focus mainly on the development and implementation of ventilation on demand concepts (VOD) and systems. However, the smart and intelligent, safe “Mine of the Future” demands the further development of advanced and adaptive ventilation systems.

Author: Dr.-Ing. Elisabeth Clausen, Institut für Bergbau, Technische Universität (TU) Clausthal, Clausthal-Zellerfeld

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Ventilation on Demand

As mining activities advanced throughout the centuries, mines increased in depth and complexity, resulting in the development of new technologies and processes. Ventilation was not only affected in terms of increased air quantities to be supplied, but controlling the airflow also gained attention. Until today, these trends are ongoing, meaning mines are still increasing in complexity, depth and machinery used, thus ventilation is facing new challenges. This paper introduces past mine development as a motor for progress and describes historic challenges in ventilation with corresponding solutions. Further on, today’s and possible future challenges are being discussed.

Authors: Felix Dicks, cand. M.Sc. Mining Engineering, und Dr.-Ing. Elisabeth Clausen, Institut für Bergbau, Technische Universität (TU) Clausthal, Clausthal-Zellerfeld

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Ventilation on Demand – Controllable Mine Fans, Applications and Limitations

Worldwide interest in developing technology for the automatic control of mine ventilation systems has existed since the 1980s and has mainly been driven by the need to save costs. Demand-oriented ventilation technology is based on the fundamental idea that those areas of the mine where a lot of work is being done should be provided with a greater flow of ventilation air, appropriate to their needs, that those parts where there is little or no activity whatsoever. In this way it is possible to increase the volume flow in the active production areas at the expense of the ventilating air that is delivered to the non-active zones. The aim is to achieve the optimum volume flow control at the lowest operating cost based on the minimum volume flow requirement in the areas concerned. This paper examines in detail the fundamental concept of ventilation on demand (VOD) and the basic approach that is being taken from today’s perspective.

Authors: Dr.-Ing. Sascha Engler, ERCOSPLAN Ingenieurgesellschaft Geotechnik und Bergbau mbH, Erfurt, Dipl.-Ing. (FH) Jens Kegenhoff und M.Sc. Matthias Papesch, Korfmann Lufttechnik GmbH, Witten

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Use of Live Sensor Data in Transient Simulations of Mine Ventilation Models

Fig. 5. An example of discrete cell method of flow transport and mixing. // Bild 5. Beispiel einer Betrachtung in diskreten Zellen. Source/Quelle: Stewart

The implementation of sensor systems to monitor mine ventilation atmospheres offers numerous safety and operational benefits to mines. Detection of various mine gases, changes to airflows and temperature, and detection of clearance of fumes or contaminants are some of the obvious benefits of using atmospheric sensors in mines. The prediction of atmospheric conditions between sensors, however, is potentially difficult, and to gain complete coverage a mine will require either many sensors or a method of extrapolating and predicting atmospheric conditions between and downstream from a sparser array of sensors.

A transient simulation computer model technique is demonstrated to predict the time based changes to atmosphere downstream from sensors.

Authors: Craig M Stewart, School of Mechanical and Mining Engineering at the University of Queensland and Managing Director, CHASM Consulting, Brisbane/Australia, Saiied M. Aminossadati and Mehmet S. Kizil, School of Mechanical and Mining Engineering at the University of Queensland, Brisbane/Australia

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Photoionization Detectors (PIDs) – Theory, Uses and Applications

Photoionization technology and operation PIDs effectively detect and monitor for numerous hazardous substances, providing maximum benefit and safety to users. While many hazardous gas detection methods are available, photoionization detectors offer the combination of speed of response, ease of use and maintenance, small size, and ability to detect low levels, including most volatile organic compounds (VOCs).

Author: Berg-Ing. Heinz Engelke, Key Account Manager, MSA Deutschland GmbH, Essen/Germany

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Refuge Chambers in Underground Coal Mines – Do They Represent a Good Strategy to Manage Emergencies?

Fig. 3. Example of a SCSR changeover station in underground coal mines (13). // Bild 3. Beispiel für eine Station zum Austausch von Selbstrettern im untertägigen Kohlebergbau (13).

The 2006 Sago, Darby, and Aracoma mine disasters in the USA forced the US government to implement legislation (MINER Act) that, among other measures, requires all US underground coal mines to install and maintain refuge chambers to manage emergencies in fires or explosions. However, there is still a debate on whether this is a good strategy. Australian coal mines adopt a strategy that focuses on instructing mine workers to self-escape to the surface. They are not required to use refuge chambers by Australian mine safety legislation. This paper discusses these two strategies and analyses their merits and problems.

Author: Adrian Halim, Luleå University of Technology, Luleå/Swede

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What Can Go Wrong with Mine Refuge Chambers?

Following the 2006 explosion at the Sago mine in West Virginia/USA twelve miners were trapped without communications for 47 h in a self-made barricade. When mine rescuers finally arrived, eleven of the twelve had died of CO poisoning. This prompted the US government to enact the MINER Act and follow-up regulation, requiring all underground coal mines to maintain mobile underground refuge chambers that provide life support for up to 96 h.

This paper examines some of the engineering challenges associated with refuge chambers, including:

  1. the airlock function designed to keep toxic mine gases out of the chamber;
  2. the dissipation of metabolic heat generated by the occupants inside the chamber;
  3. the resistance to withstand fires and explosions;
  4. the difficulty of making accurate air quality measurements in a condensing atmosphere inside the chamber;
  5. the ability to communicate to the outside; and
  6. the decision to shelter and the psychological pressures for miners inside the chambers.

The paper will provide an overview of current research and suggests improvements to overcome current limitations.

Author: Prof. Dr.-Ing. Jürgen Brune, Colorado School of Mines, Golden/USA

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The German Lignite Industry in 2016

Germany’s domestic lignite output decreased by 3.7 % from 178.1 mt to 171.5 mt between 2015 and 2016. 2016’s extracted lignite had a net calorific value of 52.7 mtce. 155.2 mt, or more than 90 %, of that output was used in utility power plants supplying the general public. This translates into a decrease of 2.6 % compared to the previous year. 14.2 mt was used in the factories of the lignite mining industry for the manufacture of solid products. 1.7 mt was used to generate electricity in mine-mouth power plants. 0.4 mt accounted for other sales of raw lignite and changes in stocks. Lignite’s contribution to Germany’s total gross electricity production amounted to 23.1 % in 2016.

Authors: Dipl.-Volkswirt Uwe Maaßen, Managing Director, Federal German Association of Lignite Producing Industry (DEBRIV), Bergheim/Germany, Dr. rer. pol. Hans-Wilhelm Schiffer, Executive Chair World Energy Resources, World Energy Council (WEC), London/Great Britain

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