In recent years, the Vietnamese coal mining industry has observed a dynamic increase in both its production and efficiency. In Vietnam, the most precious type of coal is anthracite, which is found in the Quang Ninh province. Industrial anthracite deposits are estimated to be over 2 billion Mg. At present, coal deposits are extracted mostly by the underground method. Coal production is gradually increasing in the underground mines in the Quang Ninh area and it is expected to constitute about 75% of the country’s total coal production in 2030. This involves an increase in the number and length of underground workings.

Cam Pha is the largest coal basin of Vietnam, located in the Quang Ninh province. So far, the yearly length of underground workings driven in underground mines in the Cam Pha basin is roughly 90÷150 km. About 84 % of these underground workings are supported by the steel arch support made of SWP profile. A similar situation can be observed in Russia, Ukraine, China, India and Turkey. In addition, the average length of repaired underground workings in the Cam Pha basin constitutes approximately 30% of the total length driven . The main cause was reported is loss of underground workings stability. This requires significant material and labour costs as well as the cost of replacing damaged elements. Additionally, it disturbs the continuity of the mining operations.

This article presents the results of the numerical modelling of the rock mass around underground workings driven in typical geo-mining conditions for underground coal mines in the Cam Pha basin, supported by the steel arch support made of SWP and V profiles. As a result of the conducted analyses, the range of failure zone of the rock mass around underground workings and the distribution of reduced stress in the steel arch support elements were determined. The effort states of the steel arch support made of SWP22 profile and V21 profile were compared. The simulations considered different inclinations angle of coal seam, following the structure of the rock mass in the Cam Pha basin. The analysis was carried out using the based-finite difference method code, FLAC2D. Based on the obtained results, actions for improving the stability of underground workings driven in the underground mines of the Cam Pha basin were proposed.

The stability of longwall mining is one of the most important and the most difficult aspects of underground coal mining. The loss of longwall stability can threaten lives, disrupt the continuity of the mining operations, and it requires significant materials and labour costs associated with replacing the damages. In fact, longwall mining stability is affected by many factors combined. Each case of longwall mining has its own unique and complex geological and mining conditions. Therefore, any case study of longwall stability requires an individual analysis. In Poland, longwall mining has been applied in underground coal mining for years. The stability of the longwall working is often examined using an empirical method. A regular longwall mining panel (F3) operation was designed and conducted at the Borynia-Zofiówka-Jastrzębie (BZJ) coal mine. During its advancement, roof failures were observed, causing a stoppage. This paper aims to identify and determine the mechanisms of these failures that occurred in the F3 longwall. A numerical model was performed using the finite difference method - code FLAC2D, representing the exact geological and mining conditions of the F3 longwall working. Major factors that influenced the stability of the F3 longwall were taken into account. Based on the obtained results from numerical analysis and the in-situ observations, the stability of the F3 longwall was discussed and evaluated. Consequently, recommended practical actions regarding roof control were put forward for continued operation in the F3 longwall panel.

Coal mining tends to face increasing stress and gas conditions when it extends to deeper levels. The mining-induced high stress and gas pressure concentrations often result in gasogeodynamic phenomena such as rock bursts and coal & gas outbursts. Over the last decades, these gasogeodynamic events have been observed more often in the Upper Silesian Coal Basin, Poland. With the increasing mining depth, these hazards not only become a serious safety risk but also represent a significant challenge for coal mining. In order to eliminate future hazards and improve safety in underground coal mines, it is necessary to apply particular methods for the prevention and mitigation of possible hazards during mining operations. Inaction or incorrect use of preventive measures may lead to gasogeodynamic events, which may result in accidents and material losses, thereby affecting the mine’s economic performance. Several coal mines operated by Jastrzębska Spółka Węglowa S.A. (JSW group), such as Pniówek, Budryk and Zofiówka coal mines have been identified as the area most prone to rock bursts as well as coal and gas outburst. Generally, the longwall panels often experience a high degree of these mining hazards. Therefore, the main aim of this research is to examine and optimise the possibility of application of prevention methods in order to reduce the frequency and scale of dangerous gasogeodynamic phenomena such as coal and gas outburst. As a main part, the field testing of the selected preventive methods that were conducted in the JSW coal mines. Based on the obtained results, the possibility of application of an optimal method for the prevention and control of coal and gas outburst in the geo-mining conditions of the JSW coal mines was discussed. The research results could be an example for other coal mines in mine planning and designing in the gasogeodynamic (coal and gas outburst) hazard-prone conditions.