The issue of transport in underground hard coal mines is very rarely described in the literature. The financial aspects of this issue are even less often analyzed. Publications in this area focus on technical issues and the safety of mining crews. More attention is paid to transport in open-pit mines. The above premises and practical needs imply the need to conduct economic analyses of transport systems in underground hard coal mines. This paper is a scientific communication, which presents the concept of a multi-criteria cost analysis as a tool to support the selection of the optimal transportation option in an underground hard coal mine. Considerations in this area have not been carried out in the relevant literature, and the problem of selecting a transportation option is a complex and necessary issue in the practice of underground mines with extensive mine workings. The methodology presented includes five cost criteria (costs of carrying out the transportation task; route expansion costs; rolling stock maintenance costs; depreciation costs; and additional personnel costs). The simultaneous application of criteria relating to utility properties in addition to cost criteria makes it possible to adopt a specific technical and organizational model of the transportation system based on the indication of the optimal solution, resulting from the mathematical construction of functions of objectives relating to utility and cost. The optimal variant of the designed system and configuration of the material transportation system in underground workings takes into consideration the following: (1) seven utility criteria (KU1—transportation task completion time; KU2—compatibility of transportation systems; KU3—continuous connectivity; KU4—co-use with other transportation tasks; KU5—safety; KU6—inconvenience; KU7—operation under overplanning conditions) and (2) five cost criteria (KK1—costs of implementing the transportation task; KK2—costs of route expansion; KK3—rolling stock maintenance costs; KK4—depreciation costs; KK5—additional personnel costs). Based on the aforementioned criteria, two objective functions are built for each option: utility and cost. They present divergent goals; therefore, they are non-cooperative functions. Both utility and costs strive for the maximum. In the developed methodology, an ideal point is usually a fictitious solution representing a set of maximum values among all the achievable values in a set of solutions, but it is impossible to achieve this simultaneously based on all the criteria. This point illustrates the maximum utility and lowest cost among the alternatives considered, which is obviously impossible for any of the variants to meet at the same time, although it indicates the possibilities of the technique and the range of costs. For the developed method, a so-called “PND” nadir point is also determined, representing the least-preferred level of achievement of all goals simultaneously, determined from the set of optimal points in the Pareto sense. The originality of the conceptual considerations undertaken stems from: filling the gap in the economic methodology of complex transportation systems evaluation; embedding considerations in the trend concerning complex transportation systems of underground mines; and focusing considerations on the pre-investment phase, making it possible to optimize costs before expenditures are incurred. Full article

Radiometric mapping could play a prominent role in locating the host rock or alteration that leads to gold mineralization. Nevertheless, in low-sulfidation epithermal gold deposits, the radiometric signatures have to be priorly characterized due to their geometry. It is comprised of a small ore vein system within the large alteration zones. The Pongkor gold mine is a low-sulfidation epithermal deposit and was selected for this purpose. The method started with the surface identification of radiometric signatures on altered and unaltered rocks near Pongkor using portable spectrometers. They are followed by the characterization of the underground mining front, which is comprised of different types of veins and host rocks. The results show that the altered rocks were characterized by a high K% and a low eTh/K ratio. Vice versa, the mineralized veins show low radioelement concentrations. Following the characterization of the geometry of alteration zones and mineralized veins, a study of the relationship between radioelements detected by radiometric mapping and gold pathfinder elements was conducted. Gold pathfinders of Mn, Fe, Zn, As, and Pb were selected for correlation studies with the radioelement. The pathfinders and radioelements were more significantly correlated in veins compared to the host rock. Based on this study, radiometric mapping has the potential and benefit of being applied in the exploration of low-sulfidation epithermal gold deposits. An alteration zone could be delineated by K or eTh/K as an anomaly indicator, and the vein bodies could also be delineated using low K or eTh as an anomaly indicator. Full article

Using a phytoremediation technique for soil remediation usually takes many years, which increases the risk that heavy metals spread into the environment during the project period. Currently, the combined remediation technique (phytoremediation and stabilization) is known as the solution to reduce this risk. In this study, the combined remediation of cadmium–arsenic-contaminated soil via phytoremediation and stabilization was studied. The pot experiment was carried out using modified fly ash (MFA) and solid waste material (steel slag (SS): pyrolusite (PY): ferrous sulfide (FS) = 1:2:8) as stabilization materials and Bidens pilosa as the accumulative plant. The characteristics of B. pilosa, including its water content, biomass, root length, plant height, and heavy metal content, were obtained after harvesting, and the reduction rate of the bioavailability of Cd and As and their physico-chemical properties, including the pH, Eh, and Ec values of the soil, were also measured. The remediation effect was evaluated according to the above indexes, and the mechanism of combined remediation was studied through the FTIR, XRD, and XPS analyses. These experiments have shown that adding an appropriate amount of MFA can enhance the absorption of heavy metals by plants in the soil and reduce the bioavailability of heavy metals in contaminated soil. In addition, the mechanism study revealed that Cd²⁺/Cd(OH)⁺ was easily adsorbed on Si-OH and MnOOH, while AsO₄³⁻ was more easily adsorbed on Fe-OH and Al-OH. Full article

Fresh groundwater, as an essential component of global water resources and a special type of mineral wealth, has a whole set of features that affect social infrastructure, the economy and the environmental well-being of the population. At the same time, groundwater is vulnerable and limited despite its replenishable nature and vast reserves. Recently, in some countries, the practice of extracting groundwater resources by private individuals on their territory has been actively spreading, but not in all states. This is considered acceptable and is enshrined in national regulations. Uncontrolled exploitation of aquifers by small water users can affect the safety of ecosystems and the depletion of drinking groundwater reserves. In this regard, the state policy and system for regulating access to groundwater resources for all subsoil users should be based on a well-thought-out concept. This article is devoted to the organizational, economic, and regulatory issues of groundwater extraction by individuals for their own needs in the Russian Federation. A comparative analysis of the state approach to groundwater extraction by private individuals in other states (mainly in the example of Germany and China) is made. The latest trends in legislation in this area are analyzed, shortcomings in the system of state regulation of groundwater use are identified, and mechanisms for legalizing the activities of individual water users are proposed. Global groundwater regulation should be based on rationality, control, safety, protection, sustainability, and future generations’ care. Full article