The prediction of landslides and other events associated with slope movement is a very serious issue in many national parks around the world. This article deals with the territory of the Malá Studená Dolina (Little Cold Valley, High Tatras National Park—Slovakia), where there are extensive talus cones, through which seasonally heavy hiking trails lead. In the last few years particularly, there have been frequent falls and landslides in the mountainous environment, which also caused several fatal injuries in 2018. For the above reasons, efforts are being made to develop a methodology for monitoring the changes of the talus cones in this specific alpine area, to determine the size, speed, and character of the morphological changes of the soil. Non-contact methods of mass data collection (laser scanning with Leica P40 and aerial photogrammetry with unmanned aerial system (UAS) DJI Phantom 4 Pro) have been used. The results of these measurements were compared and the overall suitability of both methods for measurement in such terrain evaluated. The standard deviation of the difference of surface determination (represented by the point cloud) is about 0.03 m. As such accuracy is sufficient for the purpose of monitoring talus cones and the use of UAS is easier and associated with lower risk of damage of expensive equipment, we conclude that this method is more suitable for mapping and for repeated monitoring of such terrain. The properties of the outputs of the individual measurement methods, the degree of measurement difficulty and specific measurement conditions in the mountainous terrain, as well as the economy of the individual methods, are discussed in detail.

The Pannonian basin is a major geothermal heat system in Central Europe. Its peripheral basin, the East Slovakian basin, is an example of a geothermal structure with a linear, directed heat flow ranging from 90 to 100 mW/m² from west to east. However, the use of the geothermal source is limited by several critical tectono-geologic factors: (a) Tectonics, and the associated disintegration of the aquifer block by multiple deformations during the pre-Paleogene, mainly Miocene, period. The main discontinuities of NW-SE and N-S direction negatively affect the permeability of the aquifer environment. For utilization, minor NE-SW dilatation open fractures are important, which have been developed by sinistral transtension on N–S faults and accelerated normal movements to the southeast. (b) Hydrogeologically, the geothermal structure is accommodated by three water types, namely, Na-HCO₃ with 10.9 g·L⁻¹ mineralization (in the north), the Ca-Mg-HCO₃ with 0.5–4.5 g·L⁻¹ mineralization (in the west), and Na-Cl water type containing 26.8–33.4 g·L⁻¹ mineralization (in the southwest). The chemical composition of the water is influenced by the Middle Triassic dolomite aquifer, as well as by infiltration of saline solutions and meteoric waters along with open fractures/faults. (c) Geothermally anomalous heat flow of 123–129 °C with 170 L/s total flow near the Slanské vchy volcanic chain seems to be the perspective for heat production.

This study describes the bioleaching of a flotation concentrate by acidophilic iron- and sulfur-oxidizing bacteria at ambient temperature in shake flasks. The concentrate was prepared from polymetallic Ag–Cu–Sb–siderite ores from Rožňava (Slovakia) and consisted of tetrahedrite and siderite, with small amounts of chalcopyrite, pyrite, and quartz. Biologically driven Cu and S extraction was significantly greater than the extraction in the abiotic control. The oxidation of 1 mol of tetrahedrite (nominally Cu ₁₀ ⁺ Cu ₂ ²⁺ Sb ₄ ³⁺ S ₁₃ ²⁻ ) to produce sulfate involved the transfer of 122 mol of electrons. The stoichiometry of the reaction was confirmed by gas analyses and the concentration profiles of the oxidation products and can be described by the equation Cu ₁₂ Sb ₄ S ₁₃ + 122Fe ³⁺ + 52H ₂ O → 12Cu ²⁺ + 4Sb ⁵⁺ + 13SO ₄ ²⁻ + 122Fe ²⁺ + 104H ⁺ . The rate of bacterial ferrous iron oxidation highly exceeded that of the chemical reduction of Fe ³⁺ at the tetrahedrite surface, as indicated by the high Fe ³⁺ -to-Fe ²⁺ ratio in the leaching liquors. The sulfur entity (S ²⁻ ) of tetrahedrite was oxidized ultimately to sulfate. After 120 days of tetrahedrite bioleaching, the concentration of Cu in the leaching liquor exceeded 4 g L ⁻¹ , which is equivalent to > 80% metal yield. While the recovery of Cu and S increased proportionally with time, the Sb concentration approached 40 mg L ⁻¹ , and subsequently decreased, which indicates the formation of secondary antimony minerals. Electron microprobe analyses of the solid residues showed that the alteration products are distinctly depleted in Cu and S and enriched with Sb and Fe when compared to the primary tetrahedrite. Graphical Abstract

This study demonstrated the successful recovery of zinc, lead, and copper collective concentrates from historical metal-bearing mine tailings (sulfide–polymetallic ore with a composition of 7.38% Zn, 1.45% Pb, and 0.49% Cu) using froth flotation techniques, which were originally developed during uranium ore mining. Froth flotation techniques were used to justify suitability for recovering metals. The effects of a dosage of the foaming agent Polyethylene glycol (PEG 600) at 50 and 100 g t⁻¹, collector types Aerophine 3418A (AERO), Danafloat 067 (DF), and potassium ethyl xanthate (KEX) at 50 and 80 g t⁻¹, and a suspension density of 300 and 500 g L⁻¹ on froth flotation collective concentrates were investigated. The final collective concentrate achieved recoveries exceeding 91% for lead (Pb), 88% for copper (Cu), and 87% for zinc (Zn). The obtained concentrates were analyzed using Atomic Absorption Spectroscopy (AAS) and X-ray Fluorescence Spectrometry (XRF), while selected samples were further examined via Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Spectroscopy (EDS). The resulting sulfide concentrates can subsequently be treated using suitable hydrometallurgical techniques. The application of these concentrates in metal production would help reduce the environmental burden of mining activities.

This paper investigates the effect of sodium hexametaphosphate (SHMP) depressant/dispersant in the presence of methyl isobutyl carbinol (MIBC) frother and soluble starch (SS) depressant on the flotation kinetics of talc ore. Emphasis is on a comparison between the evaluation of a custom design of experiment (DoE) using the multilinear regression analysis (MRA) and response surface methodology (RSM) approach. Although analysis of variance (ANOVA) is a good first step in the evaluation of the effect of factors on froth flotation processing, it nonetheless only reveals the effects that are the same under all conditions. In the case of SHMP, its effect on separation efficiency is positive; however, if it is used along with SS, the effect is negative. Moreover, if a higher frother dosage is used, the effect of SHMP on separation efficiency is negligible.