Emerging trends in mining industry partnerships

The article analyzes mining company partnerships in terms of four main counterparts, namely: the sovereign, owners and financial backers, the workforce, and local communities. The main characteristics of mining partnerships under the four aspects are discussed. Taxation and financial aspects are also considered. Case studies from the British coal industry and examples from Latin America are part of the article. Downsizing and labour relations are also discussed, as well as indigenous peoples' issues. The article concludes that, successful minerals companies in the future will be those that work with communities, applying the highest standards of social responsibility. This includes safety, environmental management and good business ethics.     

Field water balance of landfill final covers

Landfill covers are critical to waste containment, yet field performance of specific cover designs has not been well documented and seldom been compared in side-by-side testing. A study was conducted to assess the ability of landfill final covers to control percolation into underlying waste. Conventional covers employing resistive barriers as well as alternative covers relying on water-storage principles were monitored in large (10 x 20 m), instrumented drainage lysimeters over a range of climates at 11 field sites in the United States. Surface runoff was a small fraction of the water balance (0-10%, 4% on average) and was nearly insensitive to the cover slope, cover design, or climate. Lateral drainage from internal drainage layers was also a small fraction of the water balance (0-5.0%, 2.0% on average). Average percolation rates for the conventional covers with composite barriers (geomembrane over fine soil) typically were less than 12 mm/yr (1.4% of precipitation) at humid locations and 1.5 mm/yr (0.4% of precipitation) at arid, semiarid, and subhumid locations. Average percolation rates for conventional covers with soil barriers in humid climates were between 52 and 195 mm/yr (6-17% of precipitation), probably due to preferential flow through defects in the soil barrier. Average percolation rates for alternative covers ranged between 33 and 160 mm/yr (6 and 18% of precipitation) in humid climates and generally less than 2.2 mm/yr (0.4% of precipitation) in arid, semiarid, and subhumid climates. One-half (five) of the alternative covers in arid, semiarid, and subhumid climates transmitted less than 0.1 mm of percolation, but two transmitted much more percolation (26.8 and 52 mm) than anticipated during design. The data collected support conclusions from other studies that detailed, site-specific design procedures are very important for successful performance of alternative landfill covers.     

Competitive Displacement of Trees in Response to Environmental Change or Introduction of Exotics

Various global change factors such as natural and anthropogenic climate change, tropospheric ozone, CO₂, SO₂, and nitrogen deposition affect forest growth, but in species-specific ways. Since even small differences in growth rates between competing species can lead to eventual competitive exclusion, it is important to know the rate at which displacement might occur. Similarly, invasive species may displace native species and cause their extinction. A simulation study of displacement velocity was conducted. Competitive displacement between pairs of similar tree species in which one species has a growth advantage produced trajectories that fit an exponential decay model, leading to the use of the half-life as a useful summary statistic. At any given level of growth differential, the half-life for shade-tolerant species was found to be much longer than for shade-intolerant species due to the ability of shade-tolerant species to survive even when their growth is very slow. Trees with longer life-spans also persisted longer, but this effect was weaker than the shade-tolerance effect. Disturbances speeded up displacement by increasing turnover. For short-lived, intolerant species with a 20% disturbance rate and 20% growth suppression, the estimate of an 100-year half-life could be considered a precipitous rate of decline, with a risk of extinction at about 500 years. In the absence of disturbance, and with a 20% growth reduction or differential between competing species, half-lives for species replacement ranged from 100+ to nearly 800 years. With lesser growth differentials, half-lives are much longer. Such gradual competitive displacement processes will be very difficult to detect in the field over periods of even decades. Results of this study have implications for exotic species invasions. It is predicted that intact forest is not truly resistant to invasion, but that invasion of shade-tolerant tree species should be very slow. Invasion of shade-intolerant species is predicted to be accelerated by disturbance, as has been frequently observed. Results of the simulations were supported by data compiled from several parts of the world.     

The environmentalist who cried drought: Reactions to repeated warnings about depleting resources under conditions of uncertainty

Three studies examined the impact of warnings about depleting resources. In Study 1, participants played 16 trials of a 5-person resource dilemma game with complete resource uncertainty. After trial 12, participants were told they were close to depleting the resource, and thereafter received no additional warnings. Size of harvests dropped after the warning, but rebounded within 3 trials to pre-warning levels, a pattern stronger under low harvesting variability. In Study 2, participants received warnings after trials 12 and 16 of a 22-trial game. Again, harvesting dropped after the first warning, but rebounded to pre-warning levels within 3 trials, a pattern stronger under a short-term vs. a long-term warning. Harvesting was unaffected by the second warning. In Study 3, when participants received no feedback about others' harvests, harvesting dropped after both warnings, and was lower among those led to believe the resource would last a short number of trials.     

Combined application of QEM-SEM and hard X-ray microscopy to determine mineralogical associations and chemical speciation of trace metals

We describe the application of quantitative evaluation of mineralogy by scanning electron microscopy in combination with techniques commonly available at hard X-ray microprobes to define the mineralogical environment of a bauxite residue core segment with the more specific aim of determining the speciation of trace metals (e.g., Ti, V, Cr, and Mn) within the mineral matrix. Successful trace metal speciation in heterogeneous matrices, such as those encountered in soils or mineral residues, relies on a combination of techniques including spectroscopy, microscopy, diffraction, and wet chemical and physical experiments. Of substantial interest is the ability to define the mineralogy of a sample to infer redox behavior, pH buffering, and mineral-water interfaces that are likely to interact with trace metals through adsorption, coprecipitation, dissolution, or electron transfer reactions. Quantitative evaluation of mineralogy by scanning electron microscopy coupled with micro-focused X-ray diffraction, micro-X-ray fluorescence, and micro-X-ray absorption near edge structure (mXANES) spectroscopy provided detailed insights into the composition of mineral assemblages and their effect on trace metal speciation during this investigation. In the sample investigated, titanium occurs as poorly ordered ilmenite, as rutile, and is substituted in iron oxides. Manganese's spatial correlation to Ti is closely linked to ilmenite, where it appears to substitute for Fe and Ti in the ilmenite structure based on its mXANES signature. Vanadium is associated with ilmenite and goethite but always assumes the +4 oxidation state, whereas chromium is predominantly in the +3 oxidation state and solely associated with iron oxides (goethite and hematite) and appears to substitute for Fe in the goethite structure.     

Environmental News in Argentina,Chile, Mexico and the Philippines

From an environmental perspective, the media have raised the level of environmental awareness and, rightly or wrongly, focused the attention of citizens on specific environmental issues. Public reaction to environmental news can filter back into the media and highlight specific policy issues. The importance of the media in this respect has gained strength, particularly in developing countries, where environmental problems have become legitimate concerns, and where access to 'official' information has been historically difficult. In general, newspapers have been found to be one of the most predominant sources of environmental information available to the public, particularly in developing countries. In this paper, we summarise, briefly analyse and compare the newspaper coverage of environmental issues in Argentina, Chile, Mexico and the Philippines. Among numerous other results, it appears that the coverage of environmental issues fell considerably over the period 1990-94 despite an increase in world-wide environmental awareness. Most news reports actions by the environmental agencies (warnings and rewards, etc.). In the Philippines, however, most environmental news reports investments in pollution abatement activities by the private sector. While citizens' complaints represent a small percentage of the coverage of environmental issues, closer examination reveals that such complaints, in the vast majority of cases, trigger governmental actions (warnings) and ultimately an improvement of firms' environmental performance (investment).