Management of mining wastes through their transformation into useful sorbent

Abstract Every year a few hundred million or so tons of industrial waste are generated all over Europe. A considerable share is attributable to exploratory wastes from the mining sector and combustion byproducts. The process of their reprocessing and utilization fits into the following rules subject to intensive development, viz.: zero waste economy (Zero Waste Europe), effective use of resources (Resource Efficient Europe) as well as closed-circuit economy (Circular Economy). The article shows some research results to corroborate the concept of industrial waste processing of carbonaceous shales into sorbent materials. The applied process of carbonaceous shale calcination led to the obtaining of a material containing metakaolinite, then used in the synthesis of zeolites. The specific surface of the sorbent obtained in the aforesaid way exceeded 100 m2/g.

Thorium, uranium and rare earth mineralization in rocks of the Ugakhan gold deposit, Bodaibo ore region (Irkutsk oblast)

The paper reports on the results of studies of ore-bearing rocks of the Ugakhan gold deposit (Bodaybo district): metasandstones, metasiltstones and carbonaceous shales. The rocks consist of quartz, feldspar (albite, orthoclase), Fe-Mg chlorite, mica (muscovite, sericite) and carbonates (calcite, dolomite, anker-ite) and accessory titanite, rutile, tourmaline, zircon and apatite. All rocks contain fragments of microfossils exhibiting striking concentric zonation with alternated dark (carbonaceous matter) and light (carbonate-mica material) layers. In a range from metasandstones to carbonaceous shales, the rocks exhibit an increase in mica amount and the content (up to 3%) of carbonaceous matter, as well as the formation of regeneration rims around relict tourmaline and zircon. The REE mineralization includes silicates (REE-bearing epidote, thorite), fuorocarbonates (bastnesite) and phosphates (monazite, xenotime, ankylite), which are closely related to U minerals (uraninite, cofnite). Bastnesite, ankylite and thorite formed due to the decomposition of earlier REE-bearing epidote, whereas monazite and xenotime are the products of decomposition of apatite. Uraninite formed during lithifcation of matrix of carbon-bearing rocks and is replaced by cofnite. The thermal analysis of carbonaceous matter and the formation temperature of chlorite calculated using chlorite geothermometer (296–371 °С) indicate the transformation of rocks under conditions of sericite-chlorite subfacies of greenschist facies of metamorphism.

Sedimentary Facies of the Longmaxi Formation Shale Gas Reservoir in the Weiyuan Area Based on Elemental Characteristics

The Lower Silurian Longmaxi Formation in the southern Sichuan Basin is composed of a series of dark carbonaceous shales deposited in a hydrostatic shelf reduction environment. In this study, the ratio of uranium to thorium (U/Th), the total organic carbon (TOC), and the biological silicon content (SiBio) were selected as the characteristic parameters to precisely analyze the sedimentary environment and its impact on reservoir quality. The results show that the Weiyuan area in the Early Silurian Longmaxi period experienced two transgression-regression cycles, forming two third-class sequences, SSQ1 and SSQ2, which can be divided into six sedimentary microfacies: organic-rich siliceous argillaceous shelf, organic-rich silicon-containing argillaceous shelf, organic-rich silty argillaceous shelf, deep-water silty argillaceous shelf, shallow-water silty argillaceous shelf, and shallow-water argillaceous silty shelf microfacies. The organic-rich siliceous argillaceous shelf and organic-rich silicon-containing argillaceous shelf microfacies developed in the deepest transgressive system tract (TST1), with high U/Th, high TOC, and high SiBio, which are identified as the main control facies for reservoir development. These two microfacies are located in the middle of the study area, while a transition occurs in the east affected by the Neijiang Uplift. According to the classification criteria proposed in this article, the favourable shale gas reservoirs in Weiyuan area are characterized with high U/Th (>1.25), high TOC (>3%), and high SiBio (>15%). This paper proposed an evaluation method for shale sedimentary facies based on elemental and electrical logging characteristics, avoiding the limitations of core samples, which makes the quantitative division of shale sediments and the efficient recognition of high-quality reservoirs available. It is of great significance for delineating the potential production areas in the study area and beneficial for the scaled development of shale gas reservoirs.

Comparative Assessment of Hydrocarbon Generation Potential of Organic Matter from Shale Sediments along Isugwuato – Okigwe Axis, Anambra Basin, SE Nigeria

TRACT: The Cretaceous sediments in the Anambra Basin (SE Nigeria) consist of a cyclic succession of coals, carbonaceous shales, silty shales and siltstones interpreted as deltaic deposits. The objective of this study is to compare the hydrocarbon generation potential of organic matter from shale sediments along Isugwuato-Okigwe axis in the Anambra Basin, Nigeria. Data obtained indicates the presence of Type III kerogen with Tmax values are between 424 and 441ºC indicating that the shales are thermally immature to marginally mature with respect to petroleum generation. Hydrogen Index (HI) values range from 14 to 388.9mgHC/gTOC while S1 + S2 yields values ranging from 0.2 to 1.0mgHC/g rock, suggesting that the shale have gas generating potential. The TOC values rangesfrom 1.3 to 3.0%, an indication of a good source rock of terrestrially derived organic matter. The high oxygen index (OI) (16.3 mgCO2g-1TOC), TS (1.35) and TOC/TS (1.5) suggest deposition in a shallow marine environment. Based on the kerogen type, shales from the studied area will equally generate oil and gas if its organic matter attained sufficient thermal temperature. Keywords: Shale, kerogen type, maturity, oil generation.

Mineralogical and geochemical specificity of carbonaceous rocks from the area of Ust'-Kara astrobleme (Pay-Khoy)

We studied Upper Paleozoic (P1pt-ng) carbonaceous shales and siltstones from the area of the Ust'-Kara astrobleme (PayKhoy). We analyzed mineralogical and geochemical features of carbonaceous rocks of the target in the vicinity of the Ust'-Kara astrobleme event using a complex of modern methods to identify possible mobilization, redeposition and concentration of ore substance under intensive post-impact hydrothermal activity. Geochemical features of carbon deposits, altered by post-impact hydrothermal processes in the vicinity of the Ust'-Kara impact structure, have been determined. We found anomalous contents of Ti, Mn, Cr, Zr, Ni, Li, Co, Sc and REE. Inherent rare metal and rare earth minerals (monazite, florensite), sulfides (pyrite, chalcopyrite, marcasite, sphalerite), apatite, barite, anatase, chrome spinels were diagnosed.

TOURMALINE MINERALIZATION IN CARBONACEOUS SHALE OF THE BAIKAL DEPOSIT (SOUTH URAL)

The article discusses the geological structure of the Baikal deposit, located within the Kumak ore field and confined to the black shale of the Bredy Formation (C1bd). It has been established that the gold mineralization within the occurrence is confined mainly to the members of quartz-mica-tourmaline metasomatically altered carbonaceous shales. Gold is noted here in intergrowth with tourmaline. In terms of their chemical composition, tourmalines belong to dravite and foitite and are close to those of orogenic gold and gold-sulfide deposits. The close intergrowth of thin needle- like tourmaline and gold indicates the synchrony of their formation and allows the manifestation of Baikal deposit to be attributed to the quartz-tourmaline formation.