The safe environmental disposal of sulphide-rich copper/zine mine tailings is fast becoming a major economic factor in determining the profitability of mining operations. There have been new approaches and better technologies practised in the recent years which allow the mining industries to reduce and/or eliminate the environmental impacts of harmful mine tailings. One of these approaches is the use of high-density paste backfill (HDPB) which is consisting mainly of a mix of solid particles (with the cement) and water, containing between 70% and 85% by dry weight of solids. The increased use of HDPB has improved the reliability, and has reduced the cost of the preparation and transportation systems. This paper focuses on the potential environmental benefits of using the HDPB when tailings are acid generating, and also provides a case study conducted in an underground copper/zinc mine in northeast Turkey in order to illustrate these benefits.
Each year, mine and mill operations generate enormousamounts of two waste types – fine-grained tailings andcoarse-grained waste rocks. Fine-grained tailings are either discharged in slurry form to surface tailings dams ordelivered in cementitious form to underground mine stopes as backfilling, while coarse-grained rocks are typicallystored by depositing as a dry material in large dumps. The engineering design of surface tailings dams orunderground mine stopes is often controlled by the high compressibility and low shear strength characteristics offine-grained tailings. Cemented paste backfill CPB indicating saturated, fine-grained backfills can undergo majorconsolidation settlement during early curing stages. Thus, a better understanding of the rate and magnitude of bothdifferential and total settlement of CPB cured under stressis essential for a proper backfill geotechnical design. Theconsolidation parameters of CPB can be determined from an improved lab setup called CUAPS (curing underapplied pressure system). This setup is capable of simulating the CPB placement and curing conditions, andmeasuring the consolidation parameters of CPB cured under effective stresses ranging between 0.5 and 400 kPa.In this study, a series of one-dimensional consolidation tests were conducted on CPB samples allowing forexamination of the effects of binder type and rate as well as curing time on the compression properties (e.g.,coefficient of consolidationcv, compression indexCc, and recompression indexCr) and the final geotechnicalindex properties (e.g., void ratioef, water contentwf, and degree of saturationSf). Results showed that as the bindercontent increases, the initial resistance to consolidation increases. Thecvvalue decreases over the course of timedue to evolution of the CPB microstructure generated by the hydration process.
A large amount of solid and liquid wastes produced by mines and mills each year needs to be managed and minimized by alternative disposal methods like paste and dry stack. Increasingly strict environmental legislation and cost competitiveness also dictate the utilization of technically suitable, economically viable, environmentally acceptable, and socially responsible techniques. This paper reviews some of these techniques that could potentially reduce large volumes of mine wastes (with a focus on mine tailings and waste rocks) without causing significant environmental hazards. The new emerging techniques such as environmental desulphurization, covers built with sulphide-free tailings, co-disposal of tailings and waste rocks, geotextile tube dewatering, and use of tailings in the cement production and road construction for both industrial and environmental purposes are discussed in terms of waste minimization. The existing methods and approaches for efficient waste treatment and disposal are also discussed in this review paper.
During the geological prospecting works conducted in 2013 on Bangka Island (Indonesia), high monazite content was identified in the wastes produced during processing of cassiterite deposits. Monazite, among 250 known minerals containing REE , is one of the most important minerals as primary source of REE .The monazite content in this waste is up to 90.60%. The phase composition of the investigated tailing proves that the sources of minerals accompanying the placer sediments tin mineralization are granitoids. The tailing is composed of numerous ore minerals, including monazite, xenotime, zircon, cassiterite, malayaite, struverite, aeschynite-(Y), ilmenite, rutile, pseudorutile and anatase. Monazite grains belong to the group of cerium monazite. Its grains are characterized by high content of Ce2O3 27.12–33.50 w t.%, La2O3 up to 15.46 w t.%, Nd2O3 up to 12.87%. The total REE 2O3 + Y content ranges from 58.18 to 65.90 wt.%. Monazite grains observations (SEM -BSE) revealed the presence of porous zones filled with fine phases of minerals with U and Th content. The radiation intensity of 232Th is ATh = 340 ± 10 Bq and 238AU = 114 ± 2 Bq. High content of monazite and other REE minerals indicates that tailing is a very rich, potential source of REE s, although the presence of radioactive elements at the moment is a technological obstacle in their processing and use. The utilization of monazite bearing waste in the Indonesian Islands can be an important factor for development and economic activation of this region and an example of the good practice of circular economy rules.
Between Expressionism and Sperimentalism: Mario Monicelli and Pasquale Festa Campanile – The purpose of this study is to focus on the phenomenon of linguistic experimentalism in Italian cinema and to analyse the languages appearing in four films: medieval Italian, a mixture of Italian dialects, Latin and barbaric languages, in “The Incredible Army of Brancaleone” and “Brancaleone at the Crusades” (directed by M. Monicelli) as well as the prehistoric language in such films as “When Women Had Tails” and “When Women Lost Their Tails” (directed by P. Festa Campanile).