The dry separation methods for coal beneficiation have been regaining attention in the past decades. A number of improved or newly designed devices have been developed—one of them is a negative pressure pneumatic separator (NPPS). The said method of separation is based on the differences in the physical properties between coal and gangue minerals, such as the grain density, size, and shape. The aim of the hereby presented work was to develop working models describing the operation of the NPPS. To validate the models, the calculation results were compared with experimental results of the tests carried out in the previous study on the topic. Based on the findings it can be inferred that the models accurately predict the separation results, i.e., the majority of results are within the range of estimated measurement uncertainties. Consequently, the models allow one to optimise the process to obtain the products with desirable properties.

Hard coal is an important source of energy worldwide. Owing to the imperfections of excavation technology, most run-of-mine coals must be processed before they can be utilised as fuel. In this study, tests on the dry separation process were performed with numerous different raw hard coal and coal waste material samples, using a newly designed and constructed negative-pressure pneumatic separator (NPPS). The experiments revealed the effects of the feed-material properties and material processing conditions. These experiments were preceded by additional tests for evaluating the influence of each device operating parameter on the process, to determine the optimal method of supplying the feed material. The calorific value of the processed materials was improved by 5%–40%, while a minimal output yield of products (60%–70%) was maintained. The trials indicated that in coal material processing, the developed NPPS can be used for not only raw coal enrichment but also coal recovery from materials stored at coal-waste dumps. The main advantages of the device are its mobility, low material processing cost, and lack of water consumption during operation. Graphic

This study, conducted as part of the ROCCS project, investigates the potential of coal seams for CO₂ sequestration through in situ tests. The in situ tests, performed at Experimental Mine Barbara in Mikołów, Poland, involved injecting CO₂ through a horizontal well into a coal seam, with variable well lengths and injection parameters. The experiments included monitoring for CO₂ leakage and migration within the coal seam. The objective was to examine the correlation between the CO₂ injection rate and the coal–CO₂ contact area, monitoring for any potential leakage. The total mass of CO₂ injected was about 7700 kg. Significant leakage, probably due to the formation of preferential pathways, prevented pressure buildup in the injection well. The results provide insights into challenges regarding CO₂ injection into coal seams, with implications for the design of commercial-scale CO₂ storage installations.

This publication discusses the experiments and findings of project ROCCS (Establishing a Research Observatory to Unlock European Coal Seams for Carbon Dioxide Storage), which aimed to investigate the potential for carbon dioxide storage in coal seams. The project involved large-scale ex situ laboratory tests, where CO₂ was injected into an experimental coal seam using a high-pressure reactor at the Central Mining Institute in Poland. The reactor simulated underground conditions, and the experimental coal seam measured 3.05 m in length with a cross-section of 0.4 × 0.4 m. Parameters such as gas flow, temperatures, and pressures were monitored during the experiments. In the study conducted, the sorption capacity of coal from the Polish mine “Piast-Ziemowit” for CO₂, at a sorption pressure of 30 bar, was determined to be 4.8% by weight relative to the raw coal mass. The data collected from these ex situ tests can support the design of a potential commercial-scale CO₂ storage installation.