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[en] The 1978 issue of the Mining International Year Book marks the 91st year of publication and contains particulars of the principal and other international companies associated with the Mining Industry. The book is recognized as the foremost reference work of its kind with a coverage both wide and detailed. The many companies registered abroad are distinguished by an entry immediately beneath the title giving the date and place of incorporation; where the date of registration alone is mentioned, the company is registered in the United Kingdom. As in previous years each entry has been reviewed and, where necessary, revised in the light of additional information received since the previous volume. The information thus recorded is the latest available at the time of going to press. Special features of value and interest include cross-reference index to all principal, subsidiary and associated companies in this edition, geographical index, suppliers' directory and buyers' guide, world production table, mining areas of Australia, and professional services section
[en] Pyrite undergoes oxidation when exposed to aqueous oxygen to produce acidic leachate with high concentrations of H+, SO42−, and Fe3+. The oxidation mechanism is currently ascribed to contact between the mineral and aqueous oxygen. Consequently, management of acidic leachate from acid sulfate soils and acid mine drainage is focused on the prevention of contact between the sediment and aqueous oxygen through the surface. Intriguing though is the fact that in aquatic sediments, redox processes occur in sequence with the oxidizing agents. Among the common oxidants in aquatic sediments are O2, , Mn, and Fe, in the order of efficiency. Consequently, following the depletion of oxygen in pyrite-rich sediment, it would be expected that , followed by Mn and then Fe, would continue the oxidation process. However, evidence of anaerobic pyrite oxidation in a naturally occurring pyrite-rich sediment is limited. Few studies have investigated the process in aquatic systems but mostly in laboratory experimental set ups. In this study, pyrite oxidation in a naturally occurring pyrite-rich sediment was investigated. A section of the sediment was covered with surface surcharge, in the form of compacted fill. The section of the sediment outside the surcharged area was preserved and used as control experiment. Solid phase soil and porewater samples were subjected to elemental, mineralogical, and microbial analyses. The results show excess accumulation of sulfate and sulfide in the anoxic zones of the original sediment and beneath the surcharge, accompanied by the disappearance of , Mn, and Fe in the anoxic zones, indicating electron transfers between donors and acceptors, with pyrite as the most likely electron donor. The study outcome poses a significant challenge to the use of surface cover for the management of acidic leachate from pyrite oxidation, particularly, in areas rich in , MnO−2, or Fe.
[en] Chitosan beads (E) was first prepared by phase inversion of chitosan acetate solutions. Thiolate chitosan beads (ETB) was synthesised by soaking E in a mixture of ethanol and carbon disulfide for 7 days and then rinsed thoroughly with water and ethanol. Sulfur content of ETB is 7.88 %. The thiolation process has increased the Brunauer-Emmett-Teller (BET) surface area of E beads from 39.5 m"2/ g to 46.3 m"2/ g. ETB is categorised as macroporous material (pore aperture: 182 nm) with multiple and uniform porous layers. A new shoulder at 1594 cm"-"1 was found in Fourier Transform infrared spectroscopy (FTIR) spectra of ETB, is assigned to thiourea moiety and was confirmed by X-ray photoelectron spectroscopy (XPS) spectra. The Pb(II) sorption capacity by ETB was higher than E beads at all sorbent dosage (except 5.0 g/ L). At sorbent dosage of 5.0 g/ L, sorption capacity of Zn(II) by ETB was enhanced by 3.2 times as compared to E beads. Sorption data fitted well to linearized Freundlich isotherm model and Ho pseudo second order kinetic model. The higher K_F value of ETB than E indicated greater sorption capacity. The increase in Zn(II) and Pb(II) sorption capacities were attributed to enhanced chemisorption with thiol group in ETB beads. (author)