The metal mining industry faces many large challenges in future years, among which is the increasing need to process low-grade ores as accessible higher grade ores become depleted. This is against a backdrop of increasing global demands for base and precious metals, and rare earth elements. Typically about 99% of solid material hauled to, and ground at, the land surface currently ends up as was...

Investigations were focused on the development of a technology for phosphorus (P) recovery straight from wastewater. Facing the finiteness of the natural resources of this essential nutrient, the declared goal must be the sustainable use of available phosphorus sinks such as wastewater treatment plants (WWTP) for the generation of P rock substitutes. A feasible method for simultaneous eliminati...

Reactive fluid flow and geochemical transport in unsaturated fractured rocks have received increasing attention for studies of contaminant transport, groundwater quality, waste disposal, acid mine drainage remediation, mineral deposits, sedimentary diagenesis, and fluid-rock interactions in hydrothermal systems. This paper presents methods for modeling geochemical systems that emphasize: (1) in...

In the last decades considerable attention has been given to naturally occurring radioactive material (NORM). Within this frame, of particular concern is the phosphate fertilizer industry. In Brazil, four main industries (Ultrafertil, Copebrás, Fosfertil and Bunge Fertilizantes) are responsible for the production of 1.2x10 6 tons per year of P2O5. Phosphogypsum is the by-product of the phosphor...

one and two dimensional contaminant transport by pure diffusion through single layer of fine grained soil was investigated using one and two dimensional laboratory models. these models simulates a simple hydrogeologic situation underneath a solid waste landfill comprising a fine grained soil overlying a bed rock. sodium chloride solution was sued as a contaminant source above a compacted clayey...

A fly ash was used to increase pH and decrease arsenic leaching from an acidic mine waste. Both the amended system as well as the control system was leached with ultra pure water. pH in the control increased from 1.7 to 2.7 at the end of the experiment while the pH in the amended system decreased from 12.6 to 11.5. compared to the control the initial concentrations of arsenic decreased with alm...

Ferrous and ferric sulphates and (oxy)hydroxides can grow on pyrite surfaces and slow oxidation rates. However, in northern climates, repeated freeze/thaw cycles can cause cracks, channeling and exposure of new surfaces. In the present study, weathering in a repeated freeze/thaw experiment was compared to a regular humidity cell experiment. Introductory results (after 17 weeks) show very small ...

Because Pb is one of the most toxic elements and is found as a major contaminant in mining environments, this study aims to identify the distribution of this element in host phases issued from the alteration of mine wastes. The sampling location was a former mine near Oakland, California (USA). This mine was once a source of sulfide minerals from which sulfuric acid was made. The material discu...