Operational Tests of a Modular Installation and Transport Assembly of Steel Arch Support in Underground Excavations

The roof support, especially the ŁP yielding steel arch support, is transported and assembled in the face with the use of auxiliary machines. This activity in Polish underground mines causes numerous problems, which until present have not been solved. Currently, transport and assembly are carried out manually, while the roadheader and suspended rail are used only to a small extent. Therefore, the modular installation and transport assembly was developed jointly by FAMA Sp. z o. o. and AGH University of Science and Technology. The solution in question enables performing a number of functions (including transport and assembly of all kinds of support arches), which are not available in currently manufactured equipment. The proposed manipulator solves numerous problems occurring during the installation of the steel arch support in an underground mining excavation and significantly improves the process of drilling galleries. This innovative solution considerably differs from the existing ones, and its greatest advantage is versatility with regard to the cross-section and equipment of the roadway, as well as a wide range of functions. In addition, it can also be used for reloading works. The modular installation and transport assembly together with a platform, a temporary mechanized roof support and a mining machine, make up a mechanizes roadheader complex, which enables continuous mining, loading and installing the permanent support in underground workings.

Dynamic Evolution Law of Roof Deformation in Continuous Mining and Continuous Backfilling Method

To investigate the dynamic evolution law of roof deformation in the continuous mining and continuous backfilling (CMCB) method, the alternating bearing characteristics of coal and the backfilling body were obtained through statistical analysis. On the basis of two-step mining and the elastic foundation beam theory, the mechanical model of the entire stage roof deformation was established, and the dynamic change law of roof settlement was obtained. On the basis of the working face of CMCB in Haoyuan Coal Mine, the deformation rule of the two-step mining roof was analyzed. In the first stage of mining, the coal pillar is the main bearing structure, the deformation of the roof is small, and the distribution is wavy. In the second stage, the backfilling body gradually becomes the main bearing structure, and the deformation of the roof significantly increases and exhibits a U-shaped distribution. The results obtained by numerical simulations reveal that four-step mining increases the width of the coal pillars and the roof deformation is effectively controlled during the filling process. After the filling is completed, the roof remains stable under the support of the filling body under different filling modes; therefore, its final settlement remains consistent. Through field measurement, it was found that the CMCB method can effectively control the roof subsidence in Haoyuan Coal Mine.

Risk Assessment and Prevention of Surface Subsidence under Buildings by Cemented Paste Filling and Strip Mining Methods: A Case Study

Intensive and continuous mining of coal resources in China implies their gradual exhaustion, especially in the eastern regions. While some mines face closure, others have to extract residual coal resources under buildings, water bodies, and industrial sites. Thus, safe and efficient mining of the residual coal resources requires innovative techniques, which would account for the particular site’s geological conditions. In this study, two schemes of roadway mining with cemented paste backfilling (RMCPB) and strip mining are put forward. After analyzing the type, construction, and protection standard of the buildings, the probability integration method and the prediction model are used to assess the surface subsidence and deformation. The research results show that both schemes can control the surface deformation to a certain extent, but RMCPB combines the advantages of a high coal recovery rate and disposal of gangue waste. According to the surface subsidence predicted and measured data, the RMCPB method can effectively control the surface subsidence, deformation, and buildings’ safety. It also yields significant economic and environmental benefits.

Electrochemical and Optical Methods for the Quantification of Lead and Other Heavy Metal Ions in Liquid Samples

Minerals and elementary compounds of heavy metals are part of the ecosystem. Because of their high density and property to accumulate in stable forms, they are considered to be highly toxic to animals, plants and humans. Continuous mining activities and industrial effluents are the major sources which are adding toxic heavy metal ions into ecosystem and biota. Hence it is of utmost importance to quantify the levels of heavy metal ions in environmental and biological samples. On the other hand, it is equally important to remove the heavy metal ions and their compounds from the environmental and biological samples. That facilitates the environmental samples to be fit for using, consumption. In this regard, promising quantification methods such as electrochemical, spectrophotometric, naked eye sensing, test strips for spot analysis of heavy metal ions are considered for discussion. The main objective of this chapter is to give the overview of the most practiced quantification approaches available in the literature. Please note that reader cannot find the pin to pin publications regarding the same and that is not the aim of this book chapter.

Cemented Backfilling Mining Technology for Gently Inclined Coal Seams Using a Continuous Mining and Continuous Backfilling Method

To improve the efficiency and reduce costs of cemented-fill mining, we propose a continuous mining and continuous backfilling (CMCB) method based on the coal resources at the Yuxing mine in Inner Mongolia, China, and constructed a complete filling material transportation system. The new technology is suitable for cemented-fill mining of gently inclined coal seams. Numerical simulations were performed to investigate the dynamic migration law of surrounding rock stress using CMCB cemented-fill mining technology, and similar simulations were conducted to analyze the movement characteristics of the coal overburden. The results show that the coal pillars and filling body alternately bear and support each other during the CMCB process, which resolves the contradiction between mining and filling, achieves parallel mining and filling operations, and improves mining efficiency. The new mining mode exerts minimal disturbance to the overlying rock and effectively controls surface deformation. The engineering application of this technique is promising and provides theoretical guidance and technical support for safe and efficient mining of the same type of coal resources.

Similarity simulation study on displacement and stress changes response to coal mining in Longdong coal mine, China

The complicated geological conditions, including the Fault Sun, in East No. 2 mining sub-area of the Longdong coal mine will influence the stability of strata during mining, leading to serious geological hazards. To circumvent this issue, a similarity simulation experiment was designed and performed in this study, in which the failure characteristics and evolution of displacement and stress within the strata were investigated, and the optimum width of a waterproof coal pillar was determined. The results showed that, as the working face progressed, the coal seam roof gradually deformed, from initial caving of the immediate roof to complete movement and curved subsidence of the entire roof. Significant changes in displacement and stress within the coal seam roof were recorded, and these increased during continuous mining activity. Displacement and stress difference on either side of the fault gradually increased and reached remarkable values with increase in mining distance. On the basis of the experiment results, water inrush is believed to be caused by the interaction between mining and the fault, and, as calculated from parameters collected in field investigations, a waterproof coal pillar of 50 m width should be established to prevent Fault Sun activation, thereby reducing the risk of water inrush from neighbouring aquifers.