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Recently, a new liver allocation policy called the acuity circles (AC) framework was implemented to decrease geographic disparities in transplant metrics across donor service areas. Early analyses have examined the changes in outcomes because of the AC policy. However, perceptions among transplant surgeons and staff regarding the new policy remain unknown.A 28-item survey was sent to division chiefs and surgical directors of liver transplantation across the United States. Questions assessed the respondents' perceptions regarding center-level metrics and staff satisfaction. We used Organ Procurement and Transplantation Network data to study differences in allocation between the pre-AC implementation period (2019) and the post-AC implementation period (2020-2021).A total of 40 participants completed this ongoing survey study. Most responses were from region 8 (13%), region 10 (15%), and region 11 (13%). Sixty-three percent of respondents stated that the wait time for a suitable offer for recipients with model of end-stage liver disease score30 has decreased, whereas 50% stated that wait time for a suitable offer for recipients with model of end-stage liver disease score30 has increased. However, most respondents (75%) felt that the average cost per transplant had increased and that the rate of surgical complications and 1-y graft survival had remained the same. In most states, an observable decrease in in-state liver transplantations occurred each year between 2019 and 2021. In addition, most allocation regions reported an increase in donations after circulatory deaths between 2019 and 2021.Perceptions of the new AC policy among liver transplant surgeons in the United States remain mixed, highlighting the potential strengths and concerns regarding its future impact. Further studies should assess the effects of the AC policy on clinical outcomes and liver transplantation access.

Brine, produced as a by-product of oil extraction, when contained in evaporation ponds can cause soil salinization in the vicinity of these ponds. Native halophytes may assist revegetation and rehabilitation of these salt-affected soils. This study was conducted to investigate the revegetation and rehabilitation potential of brine-affected land using native halophytes (Tecticornia pergranulata (J.M.Black) K.A.Sheph. & Paul G.Wilson, Sclerolaena longicuspis (F.Muell.) A.J.Scott and Frankenia serpyllifolia Lindl). Soil samples from adjacent bare and vegetated areas of brine-affected land were compared to assess the physico-chemical properties associated with the vegetation cover. The salt contents of the halophytes, plant bioaccumulation, bioconcentration, and translocation factors were measured to evaluate remediation capacity of the species. We hypothesized that the halophytes reduce the ions' concentrations and thus soil salinity and sodicity. The examined halophytes were associated with a reduction in salinity and sodicity by an average of 38.5% and 33% in the top 10 cm of the soil, respectively. T. pergranulata had the highest shoot Na content (98 g/kg dry wt), bioaccumulation (14.21), and translocation (23.09) factors for Na that indicated the higher remediation potential of this species. Despite the high remediation potential of the examined species, halophytes are not able to reduce the salt content of the landscape to create conditions for the growth of glycophytes. However, the salt-affected land can be revegetated by halophytes, and halophytes probably provide a stable vegetation cover for the landscape in ecological succession. An improvement in soil physical properties is required for revegetation success.

The vegetation cover dynamics such as the spatial extent and pattern of disturbance and recovery are necessary information in mining regulation and environmental sustainability assessment. The acquisition and further analysis of these dynamics are hampered due to that the vegetation cover in mining area changes both spatially and temporally. This paper aims to assess the capability of LandTrendr algorithm and Landsat imagery in surface mining area to detect the vegetation change and characterize the historical dynamics. Curragh coal mine site in Australia was taken as an illustrative application. The spatial extent, change pattern and attributes of vegetation disturbance and recovery during 1989–2014 were detected and mapped. The overall accuracy for disturbance and recovery classification are 85.21% and 86.59% respectively. The results show that more than 2982 ha out of 4573 ha of disturbed land in entire Curragh had been covered by vegetation, while 95% of the oldest part of the operation (Central Curragh) has been seeded and rehabilitated. The average value of cumulative Disturbance to Recovery ratio for entire Curragh mine site was about 59%. This suggests that the Curragh mine has been complying with mining legislation by undertaking progressive rehabilitation and vegetation establishment efforts. The advantage of LandTrendr is that it relies on free data from Landsat archive and has straightforward operating procedures. It can provide environmental assessment and rehabilitation with serviceable data including raster maps, yearly data, cumulative Disturbance to Recovery ratio and change attributes. The LandTrendr algorithm and Landsat imagery could be supplemented with field validation and study such as recovery success analysis to facilitate better environmental assessment and mining sustainability.

This study investigated an uncapped tailings storage facility in a semi-arid subtropical climate, with the aim of understanding the hydro-geochemical processes controlling the seepage water quality...

Background and aims: Kinabalu Park is the world’s most species-rich hotspot with over 5000 plant species recorded for an area 1200 km2. The aim of this study was to characterise the vegetation on ultramafic edaphic ‘islands’ in relation to soil chemistry and elevation. Methods: In total 87 non-permanent vegetation plots were established covering 12 ultramafic edaphic ‘islands’ from 474 to 2950 m asl in which 2854 plant species in 742 genera and 188 families were recorded from 14 662 collections. Results: The results show that plant diversity decreases with elevation, but a mid-elevation (circum 1500 m asl) ‘hump’ occurs for some plant groups (orchids, pteridophytes) as a result of the presence of cloud forests. Six main vegetation classes with associated soil types were discerned: (i) Sub-Alpine Scrub; and (ii) Graminoid Scrub, both associated with Hypermagnesic Cambisols (‘hypermagnesian soils’); (iii) Montane Cloud Forest, associated with Cambisols often with accumulation of humus; (iv) Mixed Dipterocarp Forest, associated with deep Ferralsols (‘laterites’); (v) Pioneer Casuarina Scrub; (vi) Mature Mixed Casuarina Forest, both associated with Hypermagnesic Leptosols. Conclusions: We hypothesised that ‘adverse’ soil chemistry would exacerbate vegetation stunting, and the results confirmed that stunted vegetation and elevational floristic compression occurs on chemically adverse soils (mainly hypermagnesian soils). However, no clear correlation with plant diversity was found, as some of the most ‘adverse’ soils on the summit of Mount Tambuyukon had up to 132 species per 250 m2.

We estimated the evapotranspiration (ET) for an area vegetated with characteristic semi-arid native Australian plant species on ET mine waste cover systems. These systems aim to minimise drainage into underlying hazardous wastes by maximising evaporation (E) from the soil surface and transpiration from vegetation. An open top chamber was used to measure diurnal and daily ET of two plant species – Senna artemisioides (silver cassia) and Sclerolaena birchii (galvanised burr) – after a simulated rainfall event, as well as E from bare soil. Both ET and E decreased with increasing time after initial watering. Different temporal patterns were observed for daily ET from the two plant species and E from bare soil, revealing Senna artemisioides as intensive and Sclerolaena birchii as extensive water exploiters. A strong positive linear relationship was identified between ET (and E), and the atmospheric water demand represented by the vapour pressure deficit. The relationship always was more pronounced in the morning than in the afternoon, indicating a diminishing water supply from the soil associated with a declining unsaturated hydraulic conductivity of the soil in the afternoon. The slopes of the regression lines were steepest for Senna artemisioides, reflecting its intensive water-exploiting characteristics. We used the derived estimates of ET and E to predict the effect of species composition on plot ET in relation to total vegetation coverage. Although both species proved suitable for an operational ET cover system, vegetation coverage should exceed at least 50% in order to markedly influence plot ET, a value which is likely to be unsustainable in semi-arid climates.

Following the birth of the first child from a transplanted uterus in Gothenburg, Sweden, in 2014, other centers worldwide have produced scientific reports of successful uterus transplantation, as well as more recent media reports of successful births. The American Society for Reproductive Medicine recognizes uterus transplantation as the first successful medical treatment of absolute uterus factor infertility, while cautioning health professionals, patient advocacy groups, and the public about its highly experimental nature.

In 1992, BHP Coal Pty Ltd, the operator of eight open-cut coal mines in the Bowen Basin of central Queensland, embarked on a major research and development program which still continues today. The Centre for Mined Land Rehabilitation at the University of Queensland was one of the research groups that became involved with the program. A series of linked, multidisciplinary projects was developed, focusing on developing procedures to overcome, or at least minimize, the major impediments to the establishment and persistence of self-sustaining ecosystems on postmined land in the central Queensland coalfields. The research addressed both control and/or amelioration of factors that affect plant establishment, as well as control and/or management of those factors limiting growth and ongoing sustainability. Surface crusting, salinity, competition during establishment, and water availability had been identified as the major limitations to successful establishment, while among the sustainability issues, water availability, nutrient availability through the reestablishment of effective nutrient cycling, compaction, and erosion were identified as key issues. Linking both programs is the role of species selection, both plant and microbial, in fostering establishment and sustainability success (Figure 3.1). Figure 3.1 An overview of the major limitations to effective establishment and sustainability of ecosystems established on postmined land in the Bowen Basin of central Queensland. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780203740897/f817f29c-f580-4805-a8c5-e1f1c121dded/content/fig3_1.tif"/>

Open-cut coal mining in Queensland results in the formation of extensive saline overburden spoil-piles with steep slopes at the angle of repose (approximately 75% or 37o). These spoil-piles are generally found in multiple rows, several kilometers in length and heights of up to 50 or 60 m above the original landscape. They are highly dispersive and erodible. Legislation demands that these spoil piles be rehabilitated to minimize on-site and off-site discharges of sediment and salt into the surrounding environment. To achieve this, the steep slopes must be reduced, stabilized against erosion, covered with topsoil and re-vegetated. Key design criteria (slope gradient, slope length and vegetation cover) are required for the construction of post-mining landscapes that will result in acceptable erosion rates. A novel user-friendly hillslope computer model MINErosion 3.4 was developed that can accurately predict potential erosion rates from field scale hillslopes using parameters measured with a 3m laboratory tilting flume-rainfall simulator or using routinely measured soil physical and chemical properties. This model links MINErosion 2 with a novel consolidation and above ground vegetation cover factors, to the RUSLE and MUSLE equations to predict the mean annual and storm event erosion rates. The RUSLE-based prediction of the mean annual erosion rates allow minesites to derive the key design criteria of slope length, slope gradient and vegetation cover that would lead to acceptable erosion rates. The MUSLE-based prediction of storm event erosion rates will be useful as input into risk analysis of potential damage from erosion. MINErosion 3.4 was validated against erosion measured on 20 m field erosion plots established on post-mining landscapes at the Oakey Creek and Curragh coalmines, as well as on 120 and 70 m erosion plots on postmining landscapes at Kidston Gold Mine.

The foliar elemental profile of most plants reflects that of the soil on which plants grow in their natural habitat. The aim of this study was to elucidate foliar elemental profiles in the ultramafic flora of Kinabalu Park in Sabah, Malaysia. Kinabalu Park is ideal for studying plant elemental profiles because of its exceptionally rich flora and diversity in soil types. Foliar elemental profiles of 594 plant species in 99 families were analysed (totalling 1710 samples). This included 495 species (90 families) from ultramafic soils, and 120 species (45 families) from non-ultramafic soils (used as a comparison dataset). In general, the foliar elemental uptake ranges from exclusion of phytotoxic elements such as Ni and Mn, to a limited number of plant species characterised by extreme accumulation of specific elements, including trace elements (Co, Mn, Ni, Zn,), or non-essential elements (Al). This research identified hyperaccumulator behaviour (as defined by exceedances of established threshold foliar concentrations) in numerous plant species: Al > 1000 mu g g(-1) (38 spp.), Mn > 10 mg g(-1) (7 spp.), Co > 300 mu g g(-1) (3 spp.), Ni > 1000 mu g g(-1) (24 spp.) and Zn > 3000 mu g g(-1) (2 spp.). Distinct phylogenetic patterns emerged for Ni in which 18 of the identified 24 Ni hyperaccumulators were in the order Malpighiales, predominantly in the families Phyllanthaceae, Salicaceae and Violaceae.

Tolerance and accumulation of multiple trace elements simultaneously in hyperaccumulator species enable these plants to grow on sites contaminated with these elements.In this study, accumulation and tolerance to zinc (Zn) and lead (Pb) by the hyperaccumulator Noccaea caerulescens (Brassicaceae) was investigated using different Zn2+ and Pb2+ treatments in hydroponic culture.The results confirmed that N. caerulescens has a high capacity for Zn2+ accumulation while having high levels of Pb2+ tolerance. The younger plants were more tolerant to Zn2+ and Pb2+ than the older plants. The accumulation of Zn2+ in shoots or roots was not significantly affected by treatment regime or plant age. Pb accumulated mainly in the roots (0.16-0.23 wt% dry mass), confirming substantial tolerance to Pb. The concentration of phosphorus (P) in older plant shoots decreased similar to 25% in the plants treated with Zn2+, but enhanced similar to 26% in the plants treated with Zn2+ + Pb2+. The high ratio of Zn to P in both fresh and dry leaves is suggestive of the formation of insoluble Zn-salts. The Zn2+ distribution in living cells was examined using three selective fluorescent probes (Zinpyr-1, Newport Green DCF and Phen Green SIC). The fluorescent probes showed that Zn2+ was mainly located in the apoplastic space of the leaf epidermal cells. Selective fluorescent probes in combination with laser confocal microscopy proved a useful tool for elucidating cellular and tissue-level distribution of Zn2+ in living plant cells at high resolution.However, the expected vacuolar sequestration of Zn2+ was not observed, which may be explained by insufficient penetration of the fluorophores.

The present study investigated the foliar uptake rate, distribution, and retranslocation patterns of novel, synthesized zinc hydroxide-nitrate nanocrystals (ZnHN; solubility 30–50 mg Zn L−1) applied on to the adaxial surface of tomato leaves (Solanum lycopersicum L. cv. Roma). The total Zn absorption from ZnHN suspension positively increased with ZnHN application rates, but the relative efficacy started to decline at > 400 mg Zn L−1. Within the 3 weeks, total Zn recovery in the ZnHN-treated plants was 16% of the total ZnHN-Zn applied, compared to the near 90% total Zn recovery in the Zn(NO3)2-plants at the same Zn rate. Foliar-absorbed ZnHN-Zn was distributed from the treated leaves into other plant parts and preferentially translocated into the roots. Distribution of Zn from ZnHN-treated leaves to apical parts was not limited by Zn deficiency. These results demonstrate that ZnHN crystals with controlled solubility provided some sort of slow-release Zn over a certain growth period at a rate slower (but quantitatively effective) than the soluble Zn(NO3)2. The efficacy of the prolonged foliar Zn supply could be enhanced if the ZnHN suspension is sprayed over a large leaf surface area at the peak vegetative or early flowering stage.

Understanding the uptake mechanisms of heavy metals by hyperaccumulators is necessary for improving phytoextraction options to reduce metal toxicities in contaminated soils. In this study, the capacity of Zn uptake by the hyperaccumulator Noccaea caerulescens was investigated and compared to the non-hyperaccumulator Thlaspi arvense. The plants were grown under hydroponic conditions in a glasshouse. The distribution of Zn in the roots and leaves of these species was investigated by scanning electron microscopy with energy-dispersive X-ray analysis. Compared with the control with no Zn added, it was shown that prolonged Zn treatments decreased the biomass of both N. caerulescens and T. arvense. Since N. caerulescens requires Zn for growth, no Zn toxicity symptoms were observed, even when the Zn concentration in shoots reached 2.5% dry mass. T. arvense showed serious Zn toxicity only after two weeks of Zn treatment. Zn uptake by N. caerulescens was mainly translocated to the leaves while almost all of the Zn taken-up by T. arvense was retained in the roots. In N. caerulescens, increasing concentration of Zn in the supply decreased Ca and P concentrations in the shoots by up to 50 and 35%, respectively. Zn-containing crystals were abundant in both the upper and lower epidermal cells of the leaves and in the cortex of the roots during the later growth phase. Co-localization of Ca and Zn, P and S were found in leaf and root tissues. The results suggest that Zn-rich crystals with an abundance of the Zn ligand in the roots and shoots, and co-localization and interaction between Zn and other ions, may have functional significance with respect to conferring particular attributes to N. caerulescens that are not present in the non-hyperaccumulator counterpart. An understanding of these species-specific differences has relevance from the perspective of offering some insight into how particular species could contribute to a strategy for the detoxification of Zn-contaminated sites.

The present study aims to evaluate carbon recovery and analytical precision of two methods based on dry combustion for organic carbon (OC) quantification in base metal mine tailings: (1) IC subtraction method (inorganic C(IC) measured and subtracted from total C) and (2) direct OC quantification after acid pretreatment. Results showed IC subtraction method effectively hydrolyzed a range of IC minerals [calcium carbonate (CaCO3), magnesium carbonate (MgCO3), dolomite, magnesite, calcite] with satisfactory IC (as CO2 released) recovery (87–103 percent). In the direct OC quantification method, 5 M hydrochloric acid (HCl) pretreatment resulted in a satisfactory recovery (76–92 percent) of most organic compounds [ethylenediaminetetraacetic acid (EDTA), cellulose, plant litter, and charcoal], except for water-soluble OC (sucrose, 40 percent recovery). The precision of both methods declined when C levels were 10 percent. The OC values in test samples of base met...

Coal combustion by-products (CCBs) generated from coal-fired power plants have been considered in some circumstances and in some applications as alternatives for natural materials. This review focused on the beneficial use of CCBs for mine sites. The alkaline pH of CCBs has been shown to play a neutralising role for acid mine drainage and the consequent precipitation of metals from solution, mainly as metal hydroxides. Coal combustion by-products have also been used for soil restoration, having been shown to improve one or more of the physical, chemical and biological properties of degraded soils which in turn has led to improvements in revegetation outcomes. In addition, fly ash has been used as a one of the materials in engineered covers that are constructed to encapsulate and isolate potentially hazardous mine wastes. The use of CCBs for mine void backfilling has been considered an opportunity for the bulk utilization of CCBs. Backfilling of underground mine voids with these materials presents the potential to reduce acid mine drainage, limit the risk of land subsidence and minimise and control the likelihood of mine fires. Even though the proactive use of CCBs may eliminate or reduce an environmental burden that remains if separate storage or disposal of these otherwise ‘waste’ materials is required, there may be adverse side effects that could occur through such uses of CCBs, such as the leaching of deleterious elements. Therefore, in the case of their use in mine backfilling, for example, possible environmental impacts need to be assessed and monitored during a testing phase in the context of other variables, and before backfilling with such materials is used on a large-scale. There is still a lack of well-researched information on the practical use of CCBs, and their potential environmental and health effects, and in their use for mine site rehabilitation purposes, effective guidelines and regulations are also limiting factors. In most countries, government regulations regard CCBs as a waste but not a hazardous waste. However, given the high potential CCBs have in a number of roles and functions relating to mine rehabilitation and mine closure, more research at the practical level, and more engagement at a government level, is required.

At the Kidston gold mine, Australia, the direct establishment of vegetation on tailings was considered as an alternative to the use of a waste rock cover. The tailings acid/base account was used to predict plant growth limitation by acidity, and thus methods capable of identifying tailings that would acidify to pH 4.5 or lower were sought. Total S was found to be poorly correlated with acid-generating sulfide, and total C was poorly correlated with acid-neutralizing carbonate, precluding the use of readily determined total S and C as predictors of net acid generation. Therefore, the selected approach used assessment of sulfide content as a predictor of acid generation, and carbonate content as a measure of the acid-neutralizing capacity available at pH 5 and above. Using this approach, the majority of tailings (67%) were found to be non-acid generating. However, areas of potentially acid-generating tailings were randomly distributed across the dam, and could only be located by intensive sampling. The limitations imposed by the large sample numbers, and costly analysis of sulfide and carbonate, make it impractical to identify and ameliorate acid-generating areas prior to vegetation establishment. However, as only a small proportion of the tailings will acidify, a strategy of re-treating acid areas following oxidation is suggested. The findings of the present study will assist in the selection of appropriate methods for the prediction of net acid generation, particularly where more conservative measurements are required to allow vegetation to be established directly in tailings.

Steep terrain, intense rainfall, and seismic activity precluded use of conventional tailings storage facilities at the PT Freeport Indonesia (PTFI) copper–gold mine, in Papua, Indonesia. A controlled river tailings system was adopted as the only feasible way to manage the tailings. The tailings are transported to an engineered 230 km2 deposition area, which is bounded by levees on the east and west sides and is open on the south side to allow transport water and surges of rainfall to exit the area. We evaluated the performance of the ore-fed blending strategy for managing potential acid rock drainage formation of the tailings. Long-term leaching column tests and monitoring of deposited tailings provided insight on the reactivity, leaching behaviours, and neutralizing potential of the samples, and the ratio of acid neutralizing capacity (ANC): maximum potential acidity (MPA) that would ensure that the deposited tailings remain non-acid forming. We concluded that an ANC/MPA ratio >1.5 provides an adequate factor of safety to prevent acid generation and ensure long-term geochemical stability of the deposited tailings.

Ant assemblages, used widely as bioindicators of land management practices, were sampled in rehabilitated pastures and surrounding habitats at Norwich Park Coal Mine in central Queensland, Australia. As the end-use goal of a number of rehabilitated mine sites in the region is sustainable pasture-land, the aim of this study was to investigate the influence of varying grazing histories on ant fauna, to provide further understanding on the function of rehabilitated agroecosystems and multi-trophic interactions. Examination of seven study sites revealed three distinct ant assemblages, broadly reflecting mining and grazing history. Rehabilitated pastures where grazing had ceased 2 years prior to ant sampling contained low species richness with a basic ant composition, regardless of stocking rate, and was similar to ungrazed rehabilitated pasture. The rehabilitated pasture with continual low intensity grazing showed ant compositional similarities to the neighboring unmined pasture, although assemblage descriptors were intermediate between unmined and rehabilitated sites. Buffel grass (Pennisetum ciliare, basionym Cenchrus ciliaris) and other stoloniferous or rhizomatous grasses were the principal influence on ant assemblages, with grazing reducing the ground dominance of such grasses and providing a more favorable habitat for a wider range of ant species.

This analysis attempts to reconcile existing rehabilitation planning goals and implementation constraints in the form of a paradigm that considers potential and pragmatic ecosystem transformation pathways using the Australian post-mined landscape as a contextual backdrop for investigation. A feature of the framework is that ‘novel’ ecosystems and agro-ecosystems possessing a range of commercial and societal values could bridge the conceptual divide separating the ecological function of under-rehabilitated (e.g., derelict sites) versus re-instated ‘natural’ landscapes. Landscape suitability analyses are incorporated in an operative framework to emphasise the influence of regional landscape and climate in the implementation of such management strategies. Altogether, the paradigm could facilitate the identification of widely pertinent rehabilitation goals and assessment criteria with direct implications at the regional scale of post-industrial land rehabilitation.

Driven principally by government regulation and societal expectations, mining companies around the world are seeking to mitigate the environmental impacts of mining through mined land rehabilitation programs. The ultimate goal of rehabilitation is to establish an acceptable and sustainable post-mining land use. Mining companies worldwide face the challenge of specifying just what a sustainable post-mining land use will be. The problem is that while regulations require mining companies to assess post-mining land use sustainability, the mechanism for doing so and the factors that should be considered are not specified. We propose a risk-based approach to post-mining land use assessment with the aim of reducing the uncertainty of mine closure and the potential cost of repair of land degradation caused by inappropriate post-mining land use. Grazing is a commonly suggested post-mining land use, particularly in Australia where most mining activities occur on land previously used for cattle grazing. Grazing is also seen as a use suited to rehabilitated mined land because of the lower land productivity required compared to cropping. In this paper we develop a conceptual model of the factors influencing the land degradation risk posed by grazing on rehabilitated mined land. This was done through a literature review to identify potentially important risk factors, followed by a survey of graziers surrounding six open cut mines within the Bowen Basin Region of Queensland, Australia. The survey results were used to develop a profile of the risk factors likely to influence the land management behaviour of graziers within the Bowen Basin. The results of the research highlight that there are three main sets of factors that affect grazing risk on rehabilitated mined land. These are site biophysical characteristics that influence land productivity and commercial grazing viability, factors that influence the land management style of a grazier (principally stocking rate decisions), and factors that influence the commitment of a grazier to comply with any caveats placed on the management of the land. The profile of risk factors obtained for Bowen Basin graziers showed that grazing is likely to be a low risk post-mining land use where land productivity is high enough to support commercial cattle grazing and where land is managed by local graziers. Both the conceptual model and the profile of risk factors described in this paper are precursors to the development of a predictive risk assessment model.

This paper examines the minerals industry's response to sustainable development in the area of waste disposal and argues that leadership and guidance are still needed to forge collective agreement on norms and standards of practise. To encourage further debate, the paper develops a set of sustainable development principles for the disposal of mining and mineral processing wastes, and discusses the implications for current and future practise. In practise, the principles can guide waste disposal decisions through the consideration of what risk and magnitude, in any given local context, a particular management solution poses to their application. The sustainability challenge in the management of tailings and waste rock is to dispose of material, such that it is inert or, if not, stable and contained, to minimise water and energy inputs and the surface footprint of wastes and to move toward finding alternate uses. Future trends in mining and processing may compound the challenges of waste management, as lower ore grades increase the ratio of waste produced for a given unit of resource, and emphasise the urgency and need for the industry to adopt new approaches. New technologies and innovations, such as thickened tailings, dry stacking and paste backfill, have greatly increased the waste disposal methods available to meet the future challenges to sustainable development.

Rainfall ingress into sulfidic rocks or tailings from metalliferous mining operations can result in acid mine drainage. Waste rock cover systems in semiarid areas are commonly designed to retain all precipitated water within benign material, from where it is removed by evapotranspiration. The long-term effectiveness of covers is often predicted from models that are based on data obtained from single trial plots assuming that the trials are homogeneous and representative of large areas. Two cover designs were tested in semiarid monsoonal northwest Queensland: (i) 1.5 m of unconsolidated waste rock overlying 0.5 m of consolidated waste rock; and (ii) 2.0 m of unconsolidated benign waste rock. Three identical plots comprised each treatment in which water balance equation parameters were estimated from meteorological measurements and vertical arrays of soil suction and moisture sensors and seepage collection using a 3-m-deep lysimeter inserted in the waste rock. In a wet season with 900 mm of precipitation, water movement through the covers was followed through changes in moisture content, suction, and seepage. Greater differences in these parameters occurred within than between cover treatments. Water retention and water movement varied substantially and seepage ranged from 2 to 80% of total rainfall. The internal heterogeneity of hydraulic properties had more effect on cover performance than did the initial cover design. Therefore, it is important to include internal heterogeneity in mine waste cover water balance models to improve their applicability.

Sustainable development practices have become an integral part of most major mining companies’ business activities. However, the history of mining and the negative impacts it has had on the natural and social environment mean future mining activities, rightly or wrongly, will be judged against the legacies of the past and current poor performers. Legacy mine land, defined here as land which has been mined and is now being used for another purpose, or is orphaned, abandoned or derelict and in need of remedial work, is one management challenge that will be judged in the context of sustainable development. Globally, millions of such sites exist. Having criteria against which to measure progress toward or away from sustainable development goals is a key to delivering results. The aim of this research was to develop a sustainability criteria and indicators framework to suit the particular needs of legacy mine land. The resulting framework consists of 14 criteria and 72 indicators.

International audience; Phytomining technology employs hyperaccumulator plants to take up metal in harvestable plant biomass. Harvesting, drying and incineration of the biomass generates a high-grade bio-ore. We propose that ``agromining'' (a variant of phytomining) could provide local communities with an alternative type of agriculture on degraded lands; farming not for food crops, but for metals such as nickel (Ni). However, two decades after its inception and numerous successful experiments, commercial phytomining has not yet become a reality. To build the case for the minerals industry, a large-scale demonstration is needed to identify operational risks and provide ``real-life'' evidence for profitability.

Ecological restorations of contaminated sites balance the human and ecological risks of residual contamination with the benefits of ecological recovery and the return of lost ecological function and ecosystem services. Risk and recovery are interrelated dynamic conditions, changing as remediation and restoration activities progress through implementation into long-term management and ecosystem maturation. Monitoring restoration progress provides data critical to minimizing residual contaminant risk and uncertainty, while measuring ecological advancement toward recovery goals. Effective monitoring plans are designed concurrently with restoration plan development and implementation and are focused on assessing the effectiveness of activities performed in support of restoration goals for the site. Physical, chemical, and biotic measures characterize progress toward desired structural and functional ecosystem components of the goals. Structural metrics, linked to ecosystem functions and services, inform restoration practitioners of work plan modifications or more substantial adaptive management actions necessary to maintain desired recovery. Monitoring frequency, duration, and scale depend on specific attributes and goals of the restoration project. Often tied to restoration milestones, critical assessment of monitoring metrics ensures attainment of risk minimization and ecosystem recovery. Finally, interpretation and communication of monitoring findings inform and engage regulators, other stakeholders, the scientific community, and the public. Because restoration activities will likely cease before full ecosystem recovery, monitoring endpoints should demonstrate risk reduction and a successional trajectory toward the condition established in the restoration goals. A detailed assessment of the completed project's achievements, as well as unrealized objectives, attained through project monitoring, will determine if contaminant risk has been minimized, if injured resources have recovered, and if ecosystem services have been returned. Such retrospective analysis will allow better planning for future restoration goals and strengthen the evidence base for quantifying injuries and damages at other sites in the future.

Information about multi-elemental concentrations in different plant parts of tropical Ni hyperaccumulator species has the potential to provide insight into their unusual metabolism relative to a range of essential and non-essential elements, but this information is scant in the literature. As Ni hyperaccumulation, and possibly co-accumulation of other toxic elements, has been hypothesized to provide herbivore (insect) protection, there is a need to quantify a range of these elements in plant tissues and transport fluids to at least verify the possibility of this explanation. In this study, multiple elements were analyzed in a range of different plant parts and transport fluids from Ni hyperaccumulator species collected from Sabah (Malaysia). The results show preferential accumulation of Ni in leaves over woody parts, but the highest concentrations were found in the phloem tissue (up to 7.9 % in Rinorea bengalensis) and phloem sap (up to 16.9 % in Phyllanthus balgooyi), visible by a bright green coloration in the field fresh material. The amount of Ni contained in one mature R. bengalensis tree was calculated at 4.77 kg. The high Ni concentration in the flowers of Phyllanthus securinegoides could affect insect floral visitors and pollination. High concentrations of Ni in the seeds of this species also could supply the seedling with Ni and aid in herbivory protection during the first stages of development. Foliar Ca and Ni in P. cf. securinegoides and R. bengalensis are positively correlated. Low accumulation of Ca is desirable for phytomining but concentrations of Ca are high in most Ni hyperaccumulators examined, and this could have consequences for the economic viability of Ni extraction from bio ore if these species were to be used as ‘metal crops’.

In Australia, metal-contaminated sites, including those with elevated levels of copper (Cu), are frequently revegetated with endemic plants. Little is known about the responses of Australian plants to excess Cu. Acacia holosericea, Eucalyptus crebra, Eucalyptus camaldulensis, and Melaleuca leucadendra were grown in solution culture with six Cu treatments (0.1 to 40 mu M). While A. holosericea was the most tolerant to excess Cu, all of the species tested were sensitive to excess Cu when compared with exotic tree and agricultural species. The critical external concentrations for toxicity were < 0.7 mu M for all species tested. There was little differentiation between shoot-tissue Cu concentrations in normal versus treated plants, thus, the derivation of critical shoot concentrations was possible only for the most tolerant species, A. holosericea. Critical root Cu concentrations were approximately 210 mu g g(-1) (A. holosericea), 150 mu g g(-1) (E. crebra), 25 mu g g(-1) (E. camaldulensis), and 165 mu g g(-1) (M. leucadendra). These results provide the first comprehensive combination of growth responses, critical concentrations, and toxicity symptoms for three important Australian genera for use in the management of Cu-contaminated sites.

High salt levels in mine spoils have been identified as one of the major chemical limitations to plant establishment after coal mining in central Queensland. Soil solution extracts from spoils indicated that EC levels of up to 26 dS/m could be encountered. Glasshouse trials examined the emergence and growth of Eucalyptus citriodora, Eucalyptus camaldulensis and Eucalyptus populnea provenances and Acacia salicina subjected to such EC levels. Relatively low levels of salt (100 mM NaCl, or 11 dS/m) with respect to the levels encountered on mine spoils, were enough to substantially reduce the rate and percentage emergence of all eucalypt provenances. A. salicina was found to be superior to the eucalypts in its ability to emerge and survive under saline conditions. It was the only species to have seedlings emerge and survive at 200 mM NaCl (20 dS/m), and the effect of salt on decreasing seedling dry weight was less pronounced for A. salicina than for any of the eucalypts. Established plants survived the range of salt treatments far better than emerging seedlings, with survival of established plants being reduced only at 300 and 400 mM NaCl (28 and 36 dS/m, respectively). A. salicina performed significantly better at 300 and 400 mM NaCl than most of the eucalypts studied. (c) 2006 Elsevier B.V. All rights reserved.

The low-voltage synchronous rectifier buck topology suffers from low efficiency at light loads due to dissipation that does not scale with load current. In this paper we present a method for improving light-load efficiency in synchronous buck converters by reducing gate drive losses. We propose a new gate drive technique whereby the gate voltage swing dynamically scales with load current such that gate drive loss is traded for conduction loss. Since conduction losses scale with the square of load current, an optimal gate swing exists that, at light loads, is shown to be less than the supply voltage. Using this method we obtain a 6.25% increase in converter efficiency at a load current of 10 mA and operating at a constant switching frequency of 2 MHz.

Little is known about the responses of Australian plants to excess metal, including Mn. It is important to remedy this lack of information so that knowledgeable decisions can be made about managing Mn contaminated sites where inhabited by Australian vegetation. Acacia holosericea, Melaleuca leucadendra, Eucalyptus crebra and Eucalyptus camaldulensis were grown in dilute solution culture for 10 weeks. The seedlings ( 42 days old) were exposed to six Mn treatments viz., 1, 8, 32, 128, 512 and 2048 muM. The order of tolerance to toxic concentrations of Mn was A. holosericea congruent to = E. crebra < M. leucadendra < E. camaldulensis, the critical external concentrations being approximately 5.1, 5.0, 21 and 330 muM, respectively. The critical tissue Mn concentrations for the youngest fully expanded leaf and total shoots were, respectively, 265 and 215 mug g(-1) DM for A. holosericea, 445 and 495 mug g(-1) DM for M. leucadendra, 495 and 710 mug g(-1) DM for E. crebra and 7230 and 6510 mug g(-1) DM for E. camaldulensis. The high tolerance of E. camaldulensis ( as opposed to the sensitivity of E. crebra) to excess Mn raises concern about fauna feeding on the plant and is consistent with hypotheses suggesting the Eucalyptus subgenus Symphomyrtus is particularly tolerant of stress, including excess Mn. The results from this paper provide the first comprehensive combination of growth responses, critical external concentrations, critical tissue concentrations and plant toxicity symptoms for three important Australian genera, viz., Eucalyptus, Acacia and Melaleuca, for use in the management of Mn toxic sites.

Tetratheca juncea Smith (Tremandraceae) has undergone a range contraction of approx. 50 km in the last 100 years and is now listed as a vulnerable sub-shrub restricted to the central and north coast regions of New South Wales, Australia. There are approx. 250 populations in a 110 km north-south distribution and populations are usually small with fewer than 50 plants/clumps. The reproductive ecology of the species was studied to determine why seed-set is reportedly rare. Flowers are bisexual, odourless and nectarless. Flowers are presented dependentally and there are eight stamens recurved around the pistil. Anthers are poricidal, contain viable pollen and basally contain a deep-red tapetal fluid that is slightly oily. Thus flowers are presented for buzz pollinators, although none were observed at flowers during our study. The species was found to be facultatively xenogamous with only one in 50 glasshouse flowers setting seed autogamously, i.e. without pollinator assistance. Field studies revealed fertile fruit in 24 populations but production varied significantly across sites from exceedingly low (0.6 fruits per plant clump) to low (17 fruits per plant clump). Fruit-set ranged from 0 to 65%, suggesting that pollen vectors exist or that autogamy levels in the field are variable and higher than glasshouse results. Fruit production did not vary with population size, although in three of the five populations in the south-west region more than twice as much fruit was produced as in populations elsewhere. A moderately strong relationship between foliage volume and fruit : flower ratios suggests that bigger plants may be more attractive than smaller plants to pollinators. A review of Tetratheca pollination ecology revealed that several species are poorly fecund and pollinators are rare. The habitat requirements for Tetratheca, a genus of many rare and threatened species, is discussed. (C) 2003 Annals of Botany Company.

The grazing trial at Kidston Gold Mine, North Queensland, was aimed specifically to assess the uptake of metals from the tailing and the potential for unacceptable contamination of saleable meat. Further aims included estimating metal dose rates and identifying potential exposure pathways including plant uptake of heavy metals, mine tailings adhered to plants and direct ingestion of mine tailing. It was found that of the 11 metals analysed (As, Zn, Co, Cd, Cr, Sn, Pb, Sb, Hg, Se and Ni) in the animal's liver, muscle and blood during the 8-month trial period, only accumulation of arsenic and zinc occurred. A risk assessment including these two metals was conducted to determine the potential for chronic metal toxicity and long-term contamination, using the estimates of metal dose rate. It was concluded that no toxicity or long-term contamination in cattle was likely at this site. Management procedures were therefore not required at this site; however, the results highlight percent ground cover and standing dry matter (DM) as important factors in decreasing metal exposure from direct ingestion of tailings and dust adhered to plants.

� Background and Aims Globally, zinc deficiency is one of the most important nutritional factors limiting crop yield and quality. Despite widespread use of foliar-applied zinc fertilizers, much remains unknown regarding the movement of zinc from the foliar surface into the vascular structure for translocation into other tissues and the key factors affecting this diffusion. � Methods Using synchrotron-based X-ray fluorescence microscopy (m-XRF), absorption of foliar-applied zinc nitrate or zinc hydroxide nitrate was examined in fresh leaves of tomato (Solanum lycopersicum )a nd citrus ( Citrus reticulatus). � Key Results The foliar absorption of zinc increased concentrations in the underlying tissues by up to 600-fold in tomato but only up to 5-fold in citrus. The magnitude of this absorption was influenced by the form of zinc applied, the zinc status of the treated leaf and the leaf surface to which it was applied (abaxial or adaxial). Once the zinc had moved through the leaf surface it appeared to bind strongly, with limited further redistribution. Regardless of this, in these underlying tissues zinc moved into the lower-order veins, with concentrations 2- to 10-fold higher than in the adjacent tissues. However, even once in higher-order veins, the movement of zinc was still comparatively limited, with concentrations decreasing to levels similar to the background within 1‐10 mm. � Conclusions The results advance our understanding of the factors that influence the efficacy of foliar zinc fertilizers and demonstrate the merits of an innovative methodology for studying foliar zinc translocation mechanisms.

A frequently desired outcome when rehabilitating Zn toxic sites in Australia is to establish a self-sustaining native ecosystem. Hence, it is important to understand the tolerance of Australian native plants to high concentrations of Zn. Very little is known about the responses of Australian native plants, and trees in particular, to toxic concentrations of Zn. Acacia holosericea, Eucalyptus camaldulensis and Melaleuca leucadendra plants were grown in dilute solution culture for 10 weeks. The seedlings (42 days old) were exposed to six Zn treatments viz., 0.5, 5, 10, 25, 50 and 100 μM. The order of tolerance to toxic concentrations of Zn was E. camaldulensis> A. holosericea> M. leucadendra, the critical external concentrations being approximately 20, 12 and 1.5 μM, respectively. Tissue Zn concentrations increased as solution Zn increased for all species. Root tissue concentrations were higher than shoot tissue concentrations at all solution Zn concentrations. The critical tissue Zn concentrations were approximately 85 and 110 μg g−1 DM for M. leucadendra, 115 and 155 μg g−1 DM for A. holosericea and 415 and 370 μg g−1 DM for E. camaldulensis for the youngest fully expanded leaf and total shoots, respectively. The results from this paper provide the first comprehensive combination of growth responses, critical external concentrations, critical tissue concentrations and plant toxicity symptoms for three important Australian genera, viz., Eucalyptus, Acacia and Melaleuca, for use in the rehabilitation of potentially Zn toxic sites.

Waste reek dumps at the abandoned Rum Jungle uranium mine were capped with clay covers in order to limit entrance of water and oxygen into the dump, and hence to reduce generation of acid drainage. The soil covers consisted of a clay seal layer overlain by moisture retention and erosion resistant layers and stabilized with vegetation. An investigation of tills cover system, primarily at one of the dumps, was undertaken in response to the concern that the vegetation dieback apparent on some areas was spreading. Reduced vegetative cover could potentially threaten the integrity and effectiveness of the rehabilitation. Areas of vegetation dieback on soil covers were shown to be the result of Cu toxicity, The soil covers had been acidified and contaminated with Cu by capillary rise of water from pyritic waste immediately underlying the soil capping. Over time, the surface soil on areas with progressively deeper tapping is being contaminated, resulting in a gradual expansion of the bare area. The activity of Al3+ in the soil solution appears to be controlled in these contaminated soils by the solubility of an Al-SO4 mineral, resulting in nonphytotoxic Al levels in the surface soil, despite the low pH. The lower portion of the clay seal layer was sufficiently acid that Al toxicity would restrict root growth.

The effects of plant-derived smoke and of heat on the emergence of seedlings from seeds were assessed. Seeds had been stored in forest topsoil used for mine site rehabilitation. The study was carried out in a dry sclerophyll, spotted gum (Corymbia maculata), forest community at the Mount Owen open-cut coal mine in the Hunter Valley region of New South Wales. Samples of the surface 2.5 cm of topsoil were either exposed to cool smoke from eucalypt foliage for 60 min, heated to 80 degrees C, or left untreated. Seedling emergence from the seed bank in this soil was then monitored in a glasshouse. Within the first month, smoke alone promoted a 4.3-fold increase in the density of seedlings relative to control. There were 540 emergents per m(2) in the control and 2309 per m(2) in the smoke treated topsoil. Many annual and perennial herbs emerged but grasses responded most strongly to smoke. Germination in seven of the 20 grass species was promoted by smoke. Smoke promoted the germination of some introduced species as well as native species, and accelerated the rate at which seedlings emerged, although these differences sometimes declined with time. Heat also stimulated germination but smoke and heat stimuli appeared to be complementary in their promotion of seedling emergence from the topsoil seed bank. Each treatment increased the density of different species, enhanced the species richness of different components of the seed bank, and had different effects on the rate of emergence. The results suggest that increased seed germination in the field immediately following a moderate intensity fire may sometimes be the result of smoke stimulation and sometimes the result of heat stimulation of the soil seed bank. These findings may have important implications for minesite revegetation programs where topsoils are replaced after mining and rapid germination of seeds stored in these soils is required during short periods when conditions are favourable for germination.