The Behaviour of Siderite Rocks in an Experimental Imitation of Pyrometamorphic Processes in Coal-Waste Fires: Upper and Lower Silesian Case, Poland

Little is known of the influence of fluxes on the nature and the intensity of burning in coal-waste heaps. To gain some insight, two siderite samples, one each from coal-mining waste heaps in Upper- and Lower Silesian Coal Basins (Poland), were heated under identical conditions in a thermal chamber coupled to a powder X-ray di ractometer. Di erences in the behaviour of siderite phase and the products of its decomposition, mainly magnetite, wüstite, and olivine, are discussed. The waste heaps sampled underwent self-heating and self-ignition catalysed by fluxes. Though the samples are unlikely to be truly representative of the Silesian basins, the heterogeneous behaviour they displayed on heating merits description and explanation, as siderite is an important widely known flux in pyrometamorphic processes

Geochemistry and electron spin resonance of hydrothermal dickite (Nowa Ruda, Lower Silesia, Poland) : Vanadium and chromium

Geochemical analyses for trace V and Cr have been done on a representative sample of a typical hydrothermal dickite/kaolinite filling vein at Nowa Ruda. The mineralogy of the sample is comparatively simple, dickite being the principal component (ca. 91 % of the total sample). Geochemical fractionation and inductively coupled plasma-optical emission spectrometry (ICP-OES) indicate that most ( > 90 % of total metal) of the V and Cr reside in the dickite. Electron Spin Resonance (ESR) shows that most ( > 70 %) of the V in the dickite structure is in the form of vanadyl (VO2+) ions. A high concentration of Cr3+ is also detected in this structure by ESR. The combination of geochemical and spectroscopic tools applied to VO2+ and Cr3+ allow one to specify the Eh ( > 0.4 V, highly oxidizing) and pH ( 4.0, highly acidic) of the solution during the formation of dickite from the Nowa Ruda Basin. Substantial proportions of the V and Cr (as well as VO2+ and Cr3+) in the dickite structure were probably contained in an original hydrothermal acid water. We suggest that hot hydrothermal waters leached the surrounding varieties of gabbroids enriched in V and Cr for the dickite-forming solution. The results of this work have shown V and Cr are potentially reliable indicators for geochemical characterization of the physicochemical conditions of their formation. The bulk-rock V/Cr ratio in hydrothermal dickites and kaolinites from Nowa Ruda, Sonoma (California, USA), Cigar Lake (Saskatchewan, Canada) and Teslić (Bosnia and Hercegovina) is also briefly explored here as a potential tracer of redox state during their formation

Plant occurrence on burning coal waste - a case study from the Katowice-Wełnowiec dump, Poland

Coal-waste dumps superimposed on former rubbish dump frequently undergo selfheating and selfignition of organic matter dispersed in the waste. The special conditions for plant growth generated as a result have been investigated since 2008 on the municipal dump reclaimed with coal wastes in Katowice-Welnowiec, Poland. The plants observed most frequently where heating has occurred are Sisymbrium loeselii, Artemisia vulgaris, Sonchus arvensis, Chenopodium album, Achillea millefolium, Cirsium arvense, Amaranthus retrollexus, Atriplex niters and Solanum nigrum. Some new, rare species such as Portulaca oleracea, first noticed in 2011, may be added. Most of encroaching species are annual, alien archeophytes and neophytes. Native species are mainly perennials. The majority of these species show a tendency to form specimens of huge size (gigantism). The abundance of emitted CO2 and nitrogen compounds is the likely cause of this. Additionally, the plants growing there are not attacked by insects. The heating of the ground liquidates the natural seed bank. After cooling, these places are seeded by species providing seeds at that very moment (pioneer species). Heated places on the dumps allow plant growth even in the middle of winter. As the seasonal vegetation cycle is disturbed, plants may be found seeding, blooming and fruiting at the same time

Tectonic control on slow-moving Andean landslides in the Colca Valley, Peru

The Colca Valley in the Central Andes is a region characterized by the occurrence of large slow-moving landslides and a high level of seismic activity. In this study, we aimed to determine passive and active tectonic control on the formation of selected five large landslides in the Colca Valley and to assess geohazard associated with these features. For that purpose, we performed a post-landslide field survey, applied remote sensing techniques, and obtained eyewitness accounts. Recently, the need to understand mass movement processes in this region is even higher due to the establishment of the Colca y Volcanes de Andagua Geopark (Colca and Andagua Volcanoes Geopark). Our results suggest that the studied landslides usually represent a complex failure mechanism, dominated by translational sliding or rotational displacements, commonly associated with the formation of horst-and-graben like structures. We found a spatial correlation between the distribution of landslides and inherited fault network. The head scarps appear to be limited by the WNW- to NW-striking faults, whereas the lateral extent of some of the reported features seems to be connected with the NNE-striking normal faults, common in both, the Mesozoic strata and the Pleistocene-Holocene deposits

Self-heating coal waste fire monitoring and related environmental problems : case studies from Poland and Ukraine

The self-heating of coal waste dumps is considered as a serious environmental issue, wherever active or inactive coal mining has been present. This issue is introduced from two active coal mining regions from Poland (Upper Silesian Coal Basin) and Ukraine (Donetsk Coal Basin) based on mineralogy, organic petrography and geochemistry, and remote sensing techniques. Thermally affected coal wastes reveal changes recorded by organic and mineral matter. Irregular cracks and fissures appear within and at the edges of organic matter particles, which are oxidised, devolatilised and plasticised. Mineral phases underwent oxidation, dehydration, structure rebuilding and recrystallisation. Highest temperatures generated during the fire cause melting and paralava formation. During selfheating, some chalcophile elements like Hg (mostly present as HgS), Pb, Zn can be enriched and released, or different organic pollutants like phenols (originated from vitrinite particles), different PAHs with alkyl substitutes, chlorinated PAHs, or sulphur heterocycles are formed. The introduced remote sensing techniques helped to localise and monitor hot spots with different temperature ranges. Applying SWIR bands of Landsat hot spots from extremely burning dumps in Ukraine were successfully localised, however, only night-time scenes with SWIR can be used. The sun’s disturbing effects should be considered as an influential factor for both thermal imaging camera or satellite images. Thermal cameras can reveal the most detailed signs of low to high temperature anomalies with different cracks and line shapes

Crystal Chemistry of an Erythrite-Köttigite Solid Solution (Co3–xZnx) (AsO4)2·8H2O

A wide compositional range, covering about 90% of an expected erythrite-köttigite substitutional solid solution with extreme compositions of (Co2.84Mg0.14Zn0.02) (AsO4)2·8H2O and (Zn2.74Co0.27) (AsO4)2·8H2O, was revealed in a suite of samples from a polymetallic ore deposit in Miedzianka, SW Poland. Members of the solid solution series were examined by means of Electron Probe Microanalysis (EPMA), Scanning Electron Microscopy (SEM)/Energy-Dispersive Spectrometer (EDS), X-ray single-crystal and powder diffraction, and Raman spectroscopy. Metal cations were randomly distributed between two special octahedral sites in the erythrite–köttigite structure. In response to Co ↔ Zn substitutions, small but significant changes in bond distances (particularly in [AsO4] tetrahedra), rotation, and distortion of co-ordination polyhedra were observed. Two sub-series of dominant cationic substitutions (Co-Mg-Ni and Co-Fe-Zn) were noted within the arsenate series of vivianite-group minerals linked by erythrite. The paragenetic sequence erythrite → Zn-rich erythrite → Co-rich köttigite → köttigite reflects the evolution of the solution’s pH towards increased acidity and a relative increase in the concentration of Zn ions following precipitation of erythrite

Structure and thermal history of the Wełnowiec dump, Poland : a municipal dump rehabilitated with coal waste

The Wełnowiec municipal dump, Katowice, Poland, rehabilitated with coal waste, is self-heating and igniting. This paper presents a novel application of the use of electrical- and resistivity geophysical methods in the investigation of burning coal waste to help explain why the heating occurred. Geoelectrical methods allowed the internal structure of the dump to be revealed, and the municipal wastes and their rehabilitation cover containing coal waste to be differentiated. Instead of a planned 2.2-m-thick multi-barrier system, the cover consists of irregularly distributed material of varying thickness ( 5%). This caused the fire to arise 3–4 years after the coal waste deposition. In areas where the rehabilitation layer is<3m thick, a landslide enabled oxygen access, initiating self-heating. Changes in conductivity clearly identify sites of active burning where measured conductivity values are more than twice those for parts of the dump with no thermal activity. Field observations in particular, complemented to a degree by petrographic, mineralogical and geochemical data, enabled four types of heating zones to be distinguished, namely, (1) initial zones of fire overtaking new volumes of coal waste, (2) active zones with temperatures < 400–500 °C in exhalation vents, (3) overburned zones characterized by long-lasting high temperatures (800-900 °C) and (4) short-lived zones, ephemeral (< 1–2 months) with temperatures between 70 and 100 °C. The geophysical methods applied could not distinguish between these zones. The combined results strongly suggest that the use of coal waste as a remediation layer covering waste dumps should be prohibited. Coal waste which, by its nature, is too prone to unpredictable self-heating and self-ignition with the potential environmental consequences that follow

Self-Heating Coal Waste Fire Monitoring and Related Environmental Problems: Case Studies from Poland and Ukraine

The self-heating of coal waste dumps is considered as a serious environmental issue, wherever active or inactive coal mining has been present. This issue is introduced from two active coal mining regions from Poland (Upper Silesian Coal Basin) and Ukraine (Donetsk Coal Basin) based on mineralogy, organic petrography and geochemistry, and remote sensing techniques. Thermally affected coal wastes reveal changes recorded by organic and mineral matter. Irregular cracks and fissures appear within and at the edges of organic matter particles, which are oxidised, devolatilised and plasticised. Mineral phases underwent oxidation, dehydration, structure rebuilding and recrystallisation. Highest temperatures generated during the fire cause melting and paralava formation. During self-heating, some chalcophile elements like Hg (mostly present as HgS), Pb, Zn can be enriched and released, or different organic pollutants like phenols (originated from vitrinite particles), different PAHs with alkyl substitutes, chlorinated PAHs, or sulphur heterocycles are formed. The introduced remote sensing techniques helped to localise and monitor hot spots with different temperature ranges. Applying SWIR bands of Landsat hot spots from extremely burning dumps in Ukraine were successfully localised, however, only night-time scenes with SWIR can be used. The sun’s disturbing effects should be considered as an influential factor for both thermal imaging camera or satellite images. Thermal cameras can reveal the most detailed signs of low to high temperature anomalies with different cracks and line shapes

Environmental influence of gaseous emissions from selfheating coal waste dumps in Silesia, Poland

Gaseous emissions from seven self-heating coal waste dumps in two large coal mining basins, Upper and Lower Silesia (Poland), were investigated by gas chromatography (GC-FID/TCD), and the results were correlated with on-site thermal activity, stage of self-heating as assessed by thermal mapping, efflorescences, and surface and subsurface temperatures. Though typical gases at sites without thermal activity are dominated by atmospheric nitrogen and oxygen, methane and carbon dioxide are present in concentrations that many times exceed atmospheric values. On average, their concentrations are 42.7–7160 ppm, respectively. These are levels considered harmful to health and show that coal waste fire can be dangerous for some years after extinction. At thermally active sites, concentrations of CH4 and CO2 are much higher and reach 5640–51,976 ppm (aver.), respectively. A good substrate–product correlation between CO2 and CH4 concentrations indicates rapid in-dump CH4 oxidation with only insignificant amounts of CO formed. Other gas components include hydrogen, and C3–C6 saturated and unsaturated hydrocarbons. Decreasing oxygen content in the gases is temperature-dependent, and O2 removal rapidly increased at[70 C. Emission differences between both basins are minor and most probably reflect the higher maturity of coal waste organic matter in the Lower Silesia dumps causing its higher resistance to temperature, or/and a higher degree of overburning there

Thermal springs and active fault network of the central Colca River basin, Western Cordillera, Peru

Thermal springs are prevalent water discharges along the Andes of Southern Peru. They are connected with neotectonic movements and high heat flow of the Nazca-South America subduction zone. The aim of the work is to present hydrogeochemical and isotopic characteristics of thermal springs, as well as associated efflorescences precipitating in their vicinity and relationship of geothermal areas to active fault network. The study area is located in the central Colca River basin, between Sibayo and Canco in the Western Cordillera of the Andes in southern Peru. The sampled thermal springs discharge from different sedimentary and magmatic rock formations (Jurassic-Cretaceous to Quaternary) and are situated on altitude range: 1380-2140 m a.s.l. (Colca Canyon floor), 3300-3800 m a.s.l. (Colca Valley floor) and 4330-4750 m a.s.l. (N slopes of the extinct Hualca Hualca volcano). The hydrogeochemical and isotopic (delta D and delta 18O) characteristics of thermal waters in the study area indicates that the reservoir waters originate from a mixture of meteoric and magmatic fluids, with reservoir temperatures, estimated by Na-K geothermometry, varying between 180-220°C and exceeding 240°C in case of Paclla springs at the Colca Canyon floor. The temperature of the thermal water discharges varied from 30°C to 93°C. Different mixing ratio of deep-originated fluids with meteoric waters at shallow depth results in dilution of chloride (Na-Cl) waters controlled by magma degassing and by water-rock interactions and enriching with SO4-2 and HCO3- ions. TDS of these waters varied from 1370 mg/L to 4398 mg/L. Another group of thermal springs constitute outflows of shallow steam-heated meteoric water which are dominantly sulphate and bicarbonate waters, with significantly lower TDS (275-1270 mg/L). Efflorescences accompanying the studied springs form mainly white, yellow and colourless coatings, encrustations and single crystals. Dominating mineral phases are K, Al, Mg, Fe, Na, Ca, NH4 sulphates, Ca, Na carbonates and Na, Ca-Al chlorides. Elemental sulphur was also identified. In many cases, especially in the area of Paclla/Llahuar and Pinchollo, studied thermal springs show clear correlation with crustal normal and strike-slip faults. In other sectors their relation to active faults is less pronounced