Integrated Underground Mining Hazard Assessment, Management, Environmental Monitoring, and Policy Control in Pakistan

This study focused on the significance of underground mining in Pakistan, resulting in the employment of operational staff to undertake the primary tasks of this sector, such as explosions, rock excavation, mineral research, mining-supporting walls, and mine compactivity. Occupational accidents and illnesses arise due to the activities mentioned above because the working circumstances are not optimal. The decision-matrix risk-assessment (DMRA) approach, in which incidents are evaluated according to their severity and probability, was also utilized to improve working conditions, including public health and environment protection. To assess the risks and to select which actions should continue in the same manner, we highlighted hazards that need control measures and, as the last option, those that must be stopped. By taking into account the results of the study, corrective actions were proposed that can help avoid the occurrence of the presented accidents through applying occupational safety and health regulations issued by the Department of Minerals and Mines, which is a governmental entity responsible for both the issuing and the compliance to those regulations. The current study also outlined the requirements that must be reported under mining-related laws.

Changes in the Structures and Directions of Rock Excavation Research from 1999 to 2020: A Bibliometric Study

Rock excavation has been the hot spot and frontier of scientific research. Rock excavation research is in a period of rapid development. The bibliographies included in ISI Web of Knowledge database from 1999–2020 were used as data samples, and the collected data were analyzed by literature co-citation and cluster analysis using CiteSpace and VOSviewer information visualization techniques and dynamic network analysis tools. A knowledge map of the evolution of bibliometric research development is drawn to reveal the representative literature in the field of bibliometrics. The hot areas of bibliometric research are introduced. The development trend of bibliometrics is proposed. The results of the study show that the amount of the literature on rock excavation is growing rapidly. A large amount of the foreign literature is available in China, the United States, Australia, Canada, France, and other countries. The main included journals are Tunnelling and Underground Space Technology, International Journal of Rock Mechanics and Mining Sciences, “Rock Mechanics and Rock Engineering,” “Engineering Geology,” and “Bulletin of Engineering Geology and the Environment.” Keyword co-occurrence analysis includes the following contents: rock damage constitutive model, excavation damage area, numerical simulation, stability analysis support, and prediction technology of rock.

Precision Rock Excavation: Beyond Controlled Blasting and Line Drilling

The strictness of the result of an excavation, whether mechanical or by means of explosives, is naturally conditioned by its objective and, therefore, by the type of technique applied to achieve it. To attain the best results in terms of rock breakage, and with respect to the final profile, it is important to evaluate the specific excavation energy and its optimization. This study, being a revision of different techniques to achieve good quality of the final walls, focuses on evaluating the effects of those techniques on the quality of the result, in both open-pit and underground operations. Different geometries and configurations can be applied to both quarrying and tunneling blasts. This study aims to push contour blasts to their limits, and the main aspects are discussed in order to improve the blast parameters in daily practice.

Precision Rock Excavation: Beyond Controlled Blasting and Line Drilling

The strictness of the result of an excavation, whether mechanical or by means of explosives, is naturally conditioned by the objective, and therefore by the type of technique applied to achieve it. To attain the best results in terms of rock breakage and respect of the final profile, it’s important to evaluate the excavation specific energy and its optimization. This research focuses on evaluating the effects of different techniques on the quality of final walls in open-pit and underground operations. Different geometries and configurations can be applied to both quarrying and tunnelling blasts. The research is aimed to push contour blasts to their limits, and the main aspects are discussed in order to improve the blast parameters in the daily practice.

Determining operation parameters of the leverage mechanism in a mining excavator

Introduction. The paper analyzes the process of rock excavation using a front-shovel operational equipment of an open-pit excavator in the context of determining rational modes of operation for its main mechanisms (lifting and thrusting mechanisms) during the excavation. The main purpose of the study is to establish the kinematic and dynamic characteristics of the excavation process by identifying patterns of changes in the operating parameters of the main mechanisms. Research methodology includes mathematical modelling and computational experiment with the use of machines and mechanisms theory methods. Results. Dependencies were obtained to determine rational values of lifting and thrusting velocities which ensure that the bucket (top of its cutting edge) moves along a specified trajectory while excavating. A simulation model was built for the process of rock excavation carried out by front-shovel excavators, which represents a set of calculated values for the operational parameters of the main mechanisms to realize the bucket movement along a specified path and provide specified energy-force parameters on the bucket. An optimizing algorithm was developed to control the working process of an open-pit excavator and achieve required values of the operation parameters to get the bucket moving at a specified excavating velocity within the work area of the excavator. It is shown that their joint action forms a kinematic chain which connects the main mechanisms and the bucket and includes driven links of those mechanisms and elements of the operational equipment. Operation parameters of the main mechanisms were found to be formed in accordance with kinematic properties of the transmission mechanism (with the kinematic chain as its part). Scope of results. The results of the research could be used to develop a control system for the drives of the main mechanisms.