R&D prospects in the mining and metals industry

The mining and metals industry is considered more-or-less technology mature as it spends less than 1% of its revenues on R&D. In the period 2003-2008, that sector saw a very significant increase in profitability. Yet, during the same period, mining and metals companies continued to trim R&D spending, a trend that started in the early 1980s. In the near future the mining and metals industry will face significant challenges including an increased demand from the developing world counterbalanced by an overall trend to lower ore grades and with high pressure to reduce energy consumption and carbon dioxide emissions. To overcome these challenges, the mining and metals industry will likely face the need to considerably increase its R&D efforts. As the world enters a period of economic uncertainty, the sector will need to revise its approach towards R&D, reconsider its position against collaborative research with academia and other institutions, and be more creative when it comes to R&D funding.     

X-ray microspectroscopy and chemical reactions in soil microsites

Soils provide long-term storage of environmental contaminants, which helps to protect water and air quality and diminishes negative impacts of contaminants on human and ecosystem health. Characterizing solid-phase chemical species in highly complex matrices is essential for developing principles that can be broadly applied to the wide range of notoriously heterogeneous soils occurring at the earth's surface. In the context of historical developments in soil analytical techniques, we describe applications of bulk-sample and spatially resolved synchrotron X-ray absorption spectroscopy (XAS) for characterizing chemical species of contaminants in soils, and for determining the uniqueness of trace-element reactivity in different soil microsites. Spatially resolved X-ray techniques provide opportunities for following chemical changes within soil microsites that serve as highly localized chemical micro- (or nano-)reactors of unique composition. An example of this microreactor concept is shown for micro-X-ray absorption near edge structure analysis of metal sulfide oxidation in a contaminated soil. One research challenge is to use information and principles developed from microscale soil chemistry for predicting macroscale and field-scale behavior of soil contaminants.     

Salinity management using an anionic polymer in a pecan field with calcareous-sodic soil

Soil salinity and sodicity have long been recognized as the major concerns for irrigated agriculture in the Trans-Pecos Basin, where fields are being flood irrigated with Rio Grande River water that has elevated salinity. Reclamation of these salt-affected lands is difficult due to fine-texture, high shrink-swell soils with low permeability. Conventional practice of subsoiling to improve soil permeability is expensive and has had limited success on the irrigated soils that have appreciable amounts of readily weatherable Ca minerals. If these native Ca sources can be effectively used to counter sodicity, it can improve soil permeability and reduce amelioration costs. This study evaluated the effects of 3 yr of polyacrylamide (PAM) application at 10 mg L concentration during the first irrigation of the season to evaluate soil permeability, in situ Ca mineral dissolution, and leaching of salts from the effective root zone in a pecan field of El Paso County, TX. Results indicated that PAM application improved water movement throughout the effective root zone that resulted in Na leaching. Polymer application significantly decreased CaCO (estimated based on inorganic C analysis) concentrations in the top 45 cm compared with baseline levels, indicating solubilization and redistribution of calcite. The PAM application also reduced soil electrical conductivity (EC) in the top 60 cm (4.64-2.76 dS m) and sodium adsorption ratio (SAR) from 13.1 to 5.7 mmol L in the top 75-cm depths. As evidence of improved soil conditions, pecan nut yields increased by 34% in PAM-treated fields over the control. Results suggested that PAM application helped in effective use of native Ca sources present in soils of the study site and reduced Na by improving soil permeability.     

Runoff water quality during drought in a zero-order georgia piedmont pasture: nitrogen and total organic carbon

Approximately 11% of the Southern Piedmont (1.8 million ha) is used for pasture and hay production, mostly under low-input management. Few studies have investigated in the region long-term nitrogen and carbon losses in surface runoff, which can be significant. We present 1999 to 2009 hydrologic and water quality data from a rotationally grazed, 7.8-ha, zero-order pasture (W1) near Watkinsville in the Georgia Piedmont. Annual rainfall was 176 to 463 mm below the long-term average (1240 mm) in 7 of the 11 yr. There were 20 runoff events during 86 mo of below-average rainfall (deficit period), compared with 54 events during 46 mo of nondeficit period. Mean event flow-weighted concentration (in mg L) was 0.96 for nitrate-nitrogen (NO-N), 0.97 for ammonium-nitrogen (NH-N), 3.70 for total nitrogen (TN), and 9.12 for total organic carbon (TOC) ( = 43-47; limited due to instrument problem). Nutrient loads (in kg ha per event) averaged 0.04 for NO-N, 0.03 for NH-N, 0.19 for TN, and 0.54 for TOC. Total loads for N and TOC were 6 to 11 times greater from nondeficit than from deficit periods. The observed N concentrations, while well below maximum drinking water standard limits, could pose risk for eutrophication, which can be stimulated at lower concentrations. However, the ability of headwater streams, such as the one downstream of W1, to reduce nutrient concentrations might partially alleviate this concern. The results of this study point to the need to use a long-term dataset that includes measurements made in drought and wet years when evaluating the efficacy of water quality standards.     

Snorkelling and trampling in shallow-water fringing reefs: risk assessment and proposed management strategy

Shallow reefs (reef flats <1.5 m) in the northern Red Sea are impacted by growing tourism that includes swimmers, snorkellers and reef walkers but have largely been neglected in past studies. We selected a fringing reef along the lagoon of Dahab (Sinai, Egypt) as a model for a management strategy. Point-intercept line transects were used to determine substrate composition, coral community and condition, and the coral damage index (CDI) was applied. Approximately 84% of the coral colonies showed signs of damage such as breakage, partial mortality or algal overgrowth, especially affecting the most frequent coral genus Acropora. Questionnaires were used to determine the visitors' socio-economic background and personal attitudes regarding snorkelling, SCUBA-diving and interest in visiting a prospective snorkelling trail. Experiencing nature (97%) was by far the strongest motivation, and interest in further education about reef ecology and skill training was high. Less experienced snorkellers and divers--the target group for further education and skill training--were those most prepared to financially support such a trail. We therefore recommend a guided underwater snorkelling trail and restricting recreational use to a less sensitive 'ecotourism zone' while protecting the shallow reef flat. Artificial structures can complete the trail and offer the opportunity to snorkel over deeper areas at unfavourable tide or wind conditions. This approach provides a strategy for the management and conservation of shallow-water reefs, which are facing increasing human impact here and elsewhere.     

Evaluation of nitrogen retention and microbial populations in poultry litter treated with chemical, biological or adsorbent amendments

Poultry litter is a valuable nutrient source for crop production. Successful management to reduce ammonia and its harmful side-effects on poultry and the environment can be aided by the use of litter amendments. In this study, three acidifiers, two biological treatments, one chemical urease inhibitor and two adsorber amendments were added to poultry litter. Chemical, physical and microbiological properties of the litters were assessed at the beginning and the end of the experiment. Application of litter amendments consistently reduced organic N loss (0-15%) as compared to unamended litter (20%). Acidifiers reduced nitrogen loss through both chemical and microbiological processes. Adsorbent amendments (water treatment residuals and chitosan) reduced nitrogen loss and concentrations of ammonia-producing bacteria and fungi. The use of efficient, cost-effective litter amendments to maximum agronomic, environmental and financial benefits is essential for the future of sustainable poultry production.     

Balancing durability and environmental impact in concrete combining low-grade recycled aggregates and mineral admixtures

This paper investigated the effect of various amounts of low-grade recycled aggregates in concrete containing mineral admixtures at three different water-binder ratios on mechanical and environmental performance. The balance between durability and environmental impact for a given strength level similar to normal-use concrete was also examined using analytic hierarchy process. Results showed that increasing the water-binder ratio and volume of recycled aggregates reduced compressive strength and increased air permeability and drying shrinkage relative to normal aggregates. However, compared to normal-use concrete similar or better performance could be achieved, which was attributed to improvement of low-grade recycled aggregate performance when combined with fly ash. Similarly, CO₂ emissions and volume of raw materials were lower than the normal-use concrete for all mixes. Concrete mixes with low air permeability and low CO₂ footprint had the best balance of durability and environmental impact, as decreasing raw material volume tended to more greatly reduce durability.     

Evolution of a stream ecosystem in recently deglaciated terrain

Climate change and associated glacial recession create new stream habitat that leads to the assembly of new riverine communities through primary succession. However, there are still very few studies of the patterns and processes of community assembly during primary succession for stream ecosystems. We illustrate the rapidity with which biotic communities can colonize and establish in recently formed streams by examining Stonefly Creek in Glacier Bay, Alaska (USA), which began to emerge from a remnant glacial ice mass between 1976 and 1979. By 2002, 57 macroinvertebrate and 27 microcrustacea species had become established. Within 10 years of the stream's formation, pink salmon and Dolly Varden charr colonized, followed by other fish species, including juvenile red and silver salmon, Coast Range sculpin, and sticklebacks. Stable-isotope analyses indicate that marine-derived nitrogen from the decay of salmon carcasses was substantially assimilated within the aquatic food web by 2004. The findings from Stonefly Creek are compared with those from a long-term study of a similarly formed but older stream (12 km to the northeast) to examine possible similarities in macroinvertebrate community and biological trait composition between streams at similar stages of development. Macroinvertebrate community assembly appears to have been initially strongly deterministic owing to low water temperature associated with remnant ice masses. In contrast, microcrustacean community assembly appears to have been more stochastic. However, as stream age and water temperature increased, macroinvertebrate colonization was also more stochastic, and taxonomic similarity between Stonefly Creek and a stream at the same stage of development was <50%. However the most abundant taxa were similar, and functional diversity of the two communities was almost identical. Tolerance is suggested as the major mechanism of community assembly. The rapidity with which salmonids and invertebrate communities have become established across an entire watershed has implications for the conservation of biodiversity in freshwater habitats.     

River network structure shapes interannual feedbacks between adult sea lamprey migration and larval habitation

Adult sea lampreys (Petromyzon marinus) migrating upstream to spawn follow a pheromone released by instream larvae. The size (i.e. flow) of a tributary dilutes the concentration of this pheromone, such that the downstream propagation pattern of larval pheromone must be influenced by patterns in the relative sizes and numbers of confluent tributaries. We developed an individual-based model to explicitly test the resulting hypothesis that river network structure influences the migration decisions of adult lampreys following the larval pheromone, and in turn the distribution of larvae. First, we initialized the model using randomly generated river networks, and found a strong positive relationship between network diameter and larval aggregation. Larvae aggregated over time, and the degree and rate of this aggregation depended on network diameter. Second, we initialized the model using a river network based on the Muskegon River, Michigan, and compared model-generated larval distribution to available field survey data. We found a significant correlation between model-generated larval abundance and field-measured larval densities (r₂ = 0.54; p < 0.0001). We also found an inverse relationship between subwatershed area and the degree to which path-dependent effects influenced larval abundance in that subwatershed. Our results overall suggest that larval distribution across a watershed results from a system of context-dependent interannual feedbacks shaped by network structure and the past migratory and spawning behavior of adults.     

Robustness and vulnerability of community irrigation systems: The case of the Taos valley acequias

Traditional economic and policy analysis theory has emphasized the implementation of private or public property rights regimes in order to sustainably manage natural resources. More recent work has challenged this approach by examining the strengths and weakness of common property governance of such resources. This paper contributes to this literature by analyzing the acequia irrigation communities in northern New Mexico. Through statistical analysis, we find that the acequias’ ability to maintain collective-action as estimated by a critical performance function, crop production, is aided by water sharing agreements and access to groundwater, and that it is hampered by property rights fragmentation and urbanization.