The Influence of the Sample Preparation on the Result of Coal Propensity to Spontaneous Combustion in the High-temperature Adiabatic Method

The liability of coal to spontaneous combustion is the principal cause of mine fires. Spontaneouscombustion is one of the main threats in Polish and Vietnamese coal mines. The article presents an analysisof the spontaneous combustion of coal in mines of both countries. It is related to the natural prone of coalto spontaneous heating and consequently to its self-ignition. Despite the relevant recognition of themethods of preventing this threat, in mines, spontaneous combustion occurs during the exploitation ofcoal seams with low and very high self-ignition tendency. Apart from the technical factors related to thedesign of coal seam mining, the properties of coal have a significant impact on the occurrence ofspontaneous combustion. Their correct recognition is essential to the precautions against spontaneouscombustion for minimalizing the risk of a mine fire. Therefore, it is necessary to study the factorsinfluencing the propensity of coal to spontaneous heating. A review of the methods used to determine thepropensity of coal to spontaneous combustion is presented in the article. Based on the high-temperaturemethod of determining the propensity of coals to spontaneous combustion, the influence of selectedfactors related to samples' preparation for testing on the determination result was investigated. Theinfluence of the fractional decomposition and the moisture content in the prepared samples on thedetermination result was demonstrated. The presented research results may improve research proceduresfor determining the propensity of coal to spontaneous combustion.

Impacts of coal mine fire-related PM2.5 on the utilisation of ambulance and hospital services for mental health conditions

Climate change and an increase in the number of major fire events occurring around the world have drawn attention to the importance of understanding the association between air pollution events and mental health. In 2014, the Morwell open-cut brown coal mine adjacent to the Hazelwood power station in the Latrobe Valley region of Victoria, Australia, caught fire as a result of nearby wildfires, and exposed the local community to a prolonged period of deteriorated air quality. The aim of this study was to examine how exposure to coal mine fire-related fine particulate matter (PM2.5) during the event affected the utilisation of local health services for mental health conditions (ambulance attendances; emergency department (ED) presentations; hospital admissions). A time-series analysis indicated that mine fire-related PM2.5 exposure was associated with short-term increases in ambulance attendances and ED presentations but not hospital admissions. To allow for delays between exposure and changes in service utilisation, different lag periods were assessed. The most prominent effects were observed over a 5-day lag period where, for each 10µg/m3 increase in daily mean mine fire-related PM2.5, the risk of an ambulance attendance for anxiety increased by 34% (95%CI: 8% to 67%) and the risk of an ED presentation for depression increased by 36% (95%CI: 3% to 79%). Accordingly, ambulance and hospital services should expect to encounter an increase in the number of people seeking assistance for mental health conditions during extreme air pollution events and mechanisms need to be in place to ensure that surges in demand for mental health care during these circumstances can be accommodated.

Pre-incident planning of fires in underground hard rock mines: old and new risks

Fires in underground mines may pose a challenge to fire and rescue personnel where the complex environment and multiple influences of a fire are poorly considered during pre-incident planning. A better knowledge of pre-incident planning in underground mines would improve the safety of personnel. This study on pre-incident planning in underground mines applied data from experiments, inventories and design fire studies. A number of questions were considered related to information sources, fire modelling, capturing complexity and using fire scenarios. When performing fire modelling, empirical models could be used to complement other modelling tools. The study found that for modelling of spatially extensive mine sections, the use of ventilation network-based mine fire simulations could be a better option. Using an analytical toolbox, an iterative testing of plans and an ongoing planning process, the pre-planning challenges for a mine can be mitigated. The purpose of this study was to examine existing pre-incident planning and propose information sources, tools and specific actions for future plans.

An exploration of the trajectory of psychological distress associated with exposure to smoke during the 2014 Hazelwood coal mine fire

Due to climate change, catastrophic events such as landscape fires are increasing in frequency and severity. However, relatively little is known about the longer-term mental health outcomes of such events. Follow-up was conducted of 709 adults exposed to smoke from the 2014 Hazelwood mine fire in Morwell, Victoria, Australia. Participants completed two surveys evaluating posttraumatic distress, measured using the Impact of Events Scale-Revised (IES-R), three and six years after the mine fire. Mixed-effects regression models were used to evaluate longitudinal changes in distress. IES-R total scores increased on average by 2.6 points (95%CI: 1.2 to 3.9 points) between the two survey rounds, with increases across all three posttraumatic distress symptom clusters, particularly intrusive symptoms. This increase in distress was evident across all levels of fine particulate matter (PM2.5) exposure to the mine fire smoke. Age was an effect modifier between mine fire PM2.5 exposure and posttraumatic distress, with younger adults impacted more by exposure to the mine fire. Greater exposure to PM2.5 from the mine fire was still associated with increased psychological distress some six years later, with the overall level of distress increasing between the two survey rounds. The follow-up survey coincided with the Black Summer bushfire season in south-eastern Australia and exposure to this new smoke event may have triggered distress sensitivities stemming from exposure to the earlier mine fire. Public health responses to disaster events should take into consideration prior exposures and vulnerable groups, particularly younger adults.

Study on Numerical Simulation of Fire Danger Area Division in Mine Roadway

High-temperature poisonous smoke produced by coal mine roadway fire seriously affects miners' lives and safety. Studying the development law of high-temperature smoke in the process of mine roadway fire and then exploring the danger of roadway are of great significance to personnel safety and post-disaster rescue. In order to study this problem, the CFD numerical simulation method is used to establish a fire calculation model based on ANSYS Fluent software in the development stage of mine fire. The high-temperature flue gas flow in the roadway during the development stage of mine fire is simulated, and the variation law of temperature field and gas concentration field with time and space position under different levels of roadway in the development stage of fire is revealed. The variation rules of environmental parameters, such as temperature, CO, and CO2, are obtained by numerical calculation. Based on these, the danger zones of smoke spread in fire development stage are divided by the critical values of high-temperature smoke and toxicity evaluation index, and the mathematical fitting analysis of the evolution of the dangerous area with time is carried out. The research results have certain theoretical guiding significance for reducing underground environmental pollution and ensuring the personal safety of workers and rescuers.