Study on Strength Characteristics of Cement-Solidified Bauxite Tailings Slime

The wet slime tailing pond formed during the production of accumulated bauxite is a source of artificial debris flow hazard with high potential energy. In order to explore the effectiveness of solidification technology in processing bauxite slime, experimental study was conducted on the strength characteristics of cement-solidified slime with bauxite slime as the test object, so as to investigate the impact of cement contents and curing ages on the compressive strength of cement-solidified slime. According to the test results, the strength and deformation characteristics of solidified slime are related to the cement content, and the higher the cement admixed amount, the greater the compressive strength of solidified slime; the cement-solidified slime samples are subject to brittle failure, and with the increase of strain, the stress first rises to its peak and then decreases rapidly. The findings may serve as reference in processing bauxite slime.

Water Footprint Assessment of Carbon in Pulp Gold Processing in Turkey

This paper presents water the footprint assessment (WFA) of carbon in pulp (CIP) gold processing. The main objectives of the study are determining grey and blue water footprints and identifying the hotspots of the process. Results revealed that the total blue water footprint, including the extraction and processing of the gold, was found to be 452.40 m3/kg Au, and the grey WF to be 2300.69 m3/kg Au. According to the results, the lost return flow on the direct blue WF side has the largest contribution, with a value of 260.61 m3/kg Au, and the only source of the lost return flow is the tailing pond. On the indirect side, it is seen that the oxygen consumption used for the leaching process has the highest value, with 37.38 m3/kg. Among the nine contaminants in the mine tailings, the critical component responsible for the grey water footprint is by far arsenic, with a value of 1777 m3/kg Au. The results will be used to make recommendations for reducing water consumption in mining operations, for a better design for the environment. The study is a pioneering study, being the first implementation of water footprint assessment in a gold mine in Turkey.

Design of Experiments of hidden resources in the tailing pond – a case study for thermal power plant in Slovakia

Thermal energy is the second most important source in Slovakia after electricity, which represents almost 13.6 % of total energy production. In one of the Slovak thermal power plant Vojany (EVO) occurs by coal combustion as an undesirable slag ash mixture deposited on the tailing pond. By using environmentally sound technologies it is necessary to ensure adequate management of this waste, security and long-term stability of tailing pond. The aim of the paper is to formulate conclusions from the composition structure of EVO tailing pond and then its use. Authors realized as the main method the Design of Experiments, where the research was to investigate boreholes based on diagonal and cross-section. From the results obtained there was found that volume of tailing pond is 5,164,800 m3. In this volume there is 1,045,319 m3 of a low ash, which represents cca 20%, which can be repeatedly reused in coincineration with black coal. The development of combustion technology suggests that in the near future it will be possible to use the whole volume of the examined tailing pond for co-incineration, thus reclaiming of the tailing pond basin in an environmental manner.

REMEDIATION OF A TAILING POND IN EASTERN SLOVAKIA

In Eastern Slovakia, due to extensive chemical production in the past, especially production of explosives, and continuing combustion of coal, toxic chemicals, PCBs, fly ash and other substances are stored in a tailing pond. The current state of the tailing pond and the surrounding area, as well as its impact on the environment is analysed. Based on the results of the analysis remediation of the tailing pond is suggested. The closure of the tailing pond, including stabilisation of the pond material and the treatment of the pond surface, is designed. The result of the study proposes two possibilities of the use of pond after remediation – for growing crops as biomass and for building of a recreation and regeneration centre. In both the proposals, their advantages and disadvantages were evaluated. Reclamation will take place through a combination of technical and biotechnical stages. These proposals would be a great plus and benefit not only for the tailing pond but also for the environment and the surroundings of the pond.

Copper Recovery from Water of Soryinskoye Tailing Pond

The large volume of recycling waters from the Soryinskoye tailing pond (up to 1300 m3/h) offers interesting possibilities for processing concentrates despite the low copper content (5.2-16.4 mg/l). Sulfides precipitation is the most efficient method of heavy metal ions removal from water. In this study, a sulfur solution in sodium hydroxide was used as a sulfidizing agent for precipitation. Commercial liquid alkali (NaOH – 46) and commercial sulfur were the initial agents. Due to the concentrated alkali, dissolution could be carried out at 115-120∘С, which is higher than the melting point of sulfur. Stable solutions were obtained at a weight ratio of NaOH: S = 1: 1 and a sulfur concentration of 350 g/l. During the laboratory and scale-up laboratory tests, the optimal consumption of sulfidizing agent was determined (110% of the stoichiometry for the formation of Cu2S, and copper extraction into the precipitate from the solution was more than 90.0% with high selectivity towards Zn and Fe). An extended analysis of the composition of the sediment (x-ray fluorescence spectrometer SPECTRO XEPOS) obtained during pilot trials showed that the main elements are, %: sulfur 58.4; oxygen 16.2; copper 8.9; iron 5.7; calcium 4.7 and arsenic 3.8. The total fraction of impurity elements does not exceed 2.3%. This study assumes use of the product conditioning to obtain concentrate with increased copper content and sulfur return to sulfidation stage. Keywords: acid mine drainage, copper recovery, chemical treatment, sulfide precipitation

Environmentally Degraded Mining Areas of Eastern Slovakia As a Potential Object of Geotourism

The paper deals with the possibilities of further use of environmentally degraded and polluted areas on the example of (mining and industrial) activities residues in the Central Spiš region in eastern Slovakia. On the example of the Slovinky mining tailing pond, the Markušovce mining tailing pond, and two mining dumps in Rudňany, we deal with the analysis of their condition in terms of heavy metal content, as well as the real and potential alternative use of these sites. Data were collected using field trips and field research in sediment sampling in all localities and by preparing a questionnaire for opinion polls. The content of heavy metals from all four places, the results of field trips, and the questionnaire were analyzed. The article points out the current state of these objects in terms of their load with heavy metals and considers their possible alternative uses, especially in terms of geotourism or education. The implementation of geotourism in the studied sites brings along benefits, not only for visitors and students, but also has a positive impact on sites themselves and on the local community. The results of such analyses should also serve as a basis (starting point) in planning the renewal and further development of such areas.