Gold-copper Mine Research Articles

Carbon Emission Prediction Model for the Underground Mining Stage of Metal Mines

At present, the carbon emissions in China’s metal mining industry can be calculated based on the amount of energy consumed in the mining process. However, it is still difficult to predict the carbon emissions before implementation of mining engineering. There are no effective approaches that could reasonably estimate the amount of carbon emissions before mining. To this end, based on the ‘Top–down’ carbon emission accounting method recommended by the Intergovernmental Panel on Climate Change (IPCC), this study proposes a model to predict the greenhouse gases emitted in seven carbon-intensive mining stages, namely, drilling, blasting, ventilation, drainage, air compression, transportation, and backfilling. The contribution of this model is to enable a prediction of the accumulation of greenhouse gases based on the mining preliminary design of mine, rather than on the consumption of energy and materials commonly used in recent research. It also establishes the amount of carbon emissions generated by mining per unit cubic meter of ore rock as the minimum calculation unit for carbon emissions, which allows for the cost and footprint of carbon emissions in the mining process to become clearer. Then, a gold–copper mine is involved as a case study, and the greenhouse gas emissions were predicted employing its preliminary design. Among all the predicted results, the carbon emissions from air compression and ventilation are larger than others, reaching 22.00 kg CO2/m3 and 10.10 kg CO2/m3, respectively. By contrast, the carbon emissions of rock drilling, drainage, and backfilling material pumping are 5.87 kg CO2/m3, 6.80 kg CO2/m3, and 7.79 kg CO2/m3, respectively. To validate the proposed model, the calculation results are compared with the actual energy consumption data of the mine. The estimated overall relative error is only 5.08%. The preliminary predictions of carbon emissions and carbon emission costs in mining before mineral investment were realized, thus helping mining companies to reduce their investment risk.

Key factors determining the bulk ore sorting potential in a caving mine

Bulk ore sorting may add significant value to block and panel cave mines where processing feed grades are constrained by limited grade selectivity. The Cadia East gold-copper mine is a panel caving operation utilizing two different on-belt bulk ore sensors to evaluate the potential benefits of the technology. To date, there is limited reported work addressing the applicability of bulk ore sorting systems at a caving mine, where two commodities drive the economics. This indicative study is aimed at investigating the importance of various key factors on the bulk ore sorting potentials of the active and future panel caves of the Cadia East mine. Results show that for only one active cave of the mine, bulk ore sorting may be applied in the ideal scenario where grades are not affected negatively by mixing and the sorting takes place at maximum efficiency. As a general trend for all the caves, when the sorting cut-off grade is increased beyond a certain threshold, a sharp decline is observed in the sorting potentials due to the significant amounts of gold and copper deporting to the sorter rejects. In the case of a significant drop in metal prices, bulk ore sorting may only provide an opportunity to improve cave economics marginally. Results obtained by investigating the spatial change in sorting potential show that the portions of the caves with low metal grades are favourable for bulk ore sorting. In the scenario where bulk ore sorting is focused on low-grade portions, it is demonstrated that improvements in the economics of the future caves may additionally be achieved. However, as the low-grade portions represent a very small volume in the orebody, applying ore sorting on the plant conveyor may not be viable.

Whole Genome Sequence Analysis of Cupriavidus necator C39, a Multiple Heavy Metal(loid) and Antibiotic Resistant Bacterium Isolated from a Gold/Copper Mine.

Here a multiple heavy metal and antibiotic resistant bacterium Cupriavidus necator C39 (C. necator C39) was isolated from a Gold-Copper mine in Zijin, Fujian, China. C. necator C39 was able to tolerate intermediate concentrations of heavy metal(loid)s in Tris Minimal (TMM) Medium (Cu(II) 2 mM, Zn(II) 2 mM, Ni(II) 0.2 mM, Au(III) 70 μM and As(III) 2.5 mM). In addition, high resistance to multiple antibiotics was experimentally observed. Moreover, strain C39 was able to grow on TMM medium containing aromatic compounds such as benzoate, phenol, indole, p-hydroxybenzoic acid or phloroglucinol anhydrous as the sole carbon sources. The complete genome of this strain revealed 2 circular chromosomes and 1 plasmid, and showed the closest type strain is C. necator N-1T based on Genome BLAST Distance Phylogeny. The arsenic-resistance (ars) cluster GST-arsR-arsICBR-yciI and a scattered gene encoding the putative arsenite efflux pump ArsB were identified on the genome of strain C39, which thereby may provide the bacterium a robust capability for arsenic resistance. Genes encoding multidrug resistance efflux pump may confer high antibiotic resistance to strain C39. Key genes encoding functions in degradation pathways of benzene compounds, including benzoate, phenol, benzamide, catechol, 3- or 4-fluorobenzoate, 3- or 4-hydroxybenzoate and 3,4-dihydroxybenzoate, indicated its potential for degrading those benzene compounds.

Heavy Metals and Metalloid Effects on Cytogenetics in Frogs (Sylvirana nigrovittata) around the Sepon Gold-Copper Mine, Lao PDR

Abstract The objectives of the present study were to determine the concentrations of heavy metals and metalloids in frogs (Sylvirana nigrovittata) and to assess chromosome aberrations (CAs) in frogs collected from the Nam Kok River near the Sepon gold-copper mine, Lao PDR, as compared with those from a reference site. The results showed that the concentrations of As, Cd, Cr, and Mn in the frog muscle samples exceeded the standard values, and the accumulation of heavy metals in the frogs from the two sampling sites was significantly different (P <0.05), particularly Ba, Cd, Cr, Cu, Fe, Mn and Ni. Chromosome assessment of S. nigrovittata from the study site revealed 13 types of CAs, and the highest total number of CAs was isochromatid gap with a percentage of 31.80%. Furthermore, the total number of CAs, cell number with CAs and percentage of CAs in the frogs from both sites were significantly different (P <0.05). The results of this study suggest that heavy metal and metalloid from the Sepon gold-copper mine area negatively affected S. nigrovittata in terms of chromosomal defects. Keywords: Aberration, Abnormality, Amphibian, Animal, Toxicant

As(III) Exposure Induces a Zinc Scarcity Response and Restricts Iron Uptake in High-Level Arsenic-Resistant Paenibacillus taichungensis Strain NC1.

The Gram-positive bacterium Paenibacillus taichungensis NC1 was isolated from the Zijin gold-copper mine and shown to display high resistance to arsenic (MICs of 10 mM for arsenite in minimal medium). Genome sequencing indicated the presence of a number of potential arsenic resistance determinants in NC1. Global transcriptomic analysis under arsenic stress showed that NC1 not only directly upregulated genes in an arsenic resistance operon but also responded to arsenic toxicity by increasing the expression of genes encoding antioxidant functions, such as cat, perR, and gpx. In addition, two highly expressed genes, marR and arsV, encoding a putative flavin-dependent monooxygenase and located adjacent to the ars resistance operon, were highly induced by As(III) exposure and conferred resistance to arsenic and antimony compounds. Interestingly, the zinc scarcity response was induced under exposure to high concentrations of arsenite, and genes responsible for iron uptake were downregulated, possibly to cope with oxidative stress associated with As toxicity. IMPORTANCE Microbes have the ability to adapt and respond to a variety of conditions. To better understand these processes, we isolated the arsenic-resistant Gram-positive bacterium Paenibacillus taichungensis NC1 from a gold-copper mine. The transcriptome responding to arsenite exposure showed induction of not only genes encoding arsenic resistance determinants but also genes involved in the zinc scarcity response. In addition, many genes encoding functions involved in iron uptake were downregulated. These results help to understand how bacteria integrate specific responses to arsenite exposure with broader physiological responses.

3D Visualization Monitoring and Early Warning System of a Tailings Dam—Gold Copper Mine Tailings Dam in Zijinshan, Fujian, China

A 3D tailings dam visualization early warning system was developed based on GIS (geographic information system) combining ARIMA (autoregressive integrated moving average model) and 3S (RS, GIS, GPS) technology for prediction of phreatic line changes and tailing dam deformation. It was applied for monitoring and early warning for the gold–copper tailing dam in Zijinshan Dadongbei tailing pond. The system consists of equipment management, data management, prediction, monitoring and early warning, and 3D visualization modules. It is able to do data management, visualization and disaster prediction, and early warning based on 79 monitoring points of rainfall, infiltration line, and deformation of the tailing dam in the Zijinshan mine. The design and application of the system reflect its features of rich functionality, high practicality, intuitive effect, and high reference value. The system solves the problems of low visualization of monitoring data, poor management of multiple data, and feasible prediction and early warning of point–surface combination. It realizes high-precision prediction of key factors and real-time warning of disaster.

Why do Mines Fail to Obtain a Social License to Operate?: Insights from the Proposed Kallak Iron Mine (Sweden) and the Prosperity/New Prosperity Gold-Copper Mine (Canada).

Opposition to mines endures even in countries with relatively strong environmental assessment processes and regulations. Why proposed mines fail to obtain a social license to operate is analyzed by developing a framework comprised of three concepts-process legitimacy, distributional outcomes, and values compatibility-drawing from the social license to operate, interactive governance, and environmental justice literatures. The framework is applied to understand opposition from local Indigenous people to two mine projects, one in Sweden and the other in British Columbia, Canada. Evidence from interviews with Sami legal experts and Reindeer Herding Community representatives and an advisor with the Tŝilhqot'in National Government, as well as from secondary sources is used to analyze the contestation. Despite the proposed mines being situated in different governance contexts, the reasons for the opposition are markedly similar - environmental assessment processes are illegitimate, distributional outcomes unfair, and values incompatible. The comparative empirical analysis leads to refining the framework as a scaffold with values compatibility as the foundational plank, rather than three independent planks contributing to a social license to operate. The analysis offers insights into company commitments to Indigenous engagement, enhancements to process legitimacy, and evolving and paradigmatic shifts in governance processes, as articulated by Indigenous peoples and international governance mechanisms such as the 2007 United Nations Declaration on the Rights of Indigenous Peoples.

Extrapolymeric substances (EPS) in Mucilaginibacter rubeus P2 displayed efficient metal(loid) bio-adsorption and production was induced by copper and zinc

Strains of the genus Mucilaginibacter, belonging to the phylum Bacteroidetes, have been noted for exhibiting high genome plasticity and for the vigorous production of extracellular polymeric substances (EPS). Here we analyzed the composition and properties of EPS generated by M. rubeus P2, isolated from a gold-copper mine and exhibiting extremely high resistance to multiple heavy metals. Production of EPS increased significantly upon exposure to elevated concentrations of Cu(II) and Zn(II), but not Au(III). In addition, the EPS produced by M. rubeus P2 displayed extremely high bio-adsorption of As(III), Cu(II) and Au(III), but not of Zn(II). Moreover, EPS production in Mucilaginibacter rubeus P2 exposed to 1 mM of Cu(II) was 8.5 times higher than EPS production in the same strain without metal (loid)-exposure. These findings constitute the basis for a future use of these EPS-overproducing bacteria in bioremediation of heavy metal contaminated environments. The functional groups, especially –SH, CO, and N–H/C–N in the fingerprint zone of glutathione (GSH) and polysaccharides-like components of EPS, were the main components of EPS involved in both Zn(II) and Cu(II) binding and removal. Around 31.22% and 5.74% of Cu(II)-treated EPS was shown to exist as (CO) structures and these structures were converted into C–OH and O–C–O upon exposure to Cu(II), respectively. In contrast, (C–OH/C–O–C/P–O–C) groups in EPS were observed to be positively correlated to increasing concentrations of Zn(II) in strain P2. Furthermore, the complete genome of M. rubeus P2 helped us to identify 350 genes involved in carbohydrate metabolism, some of which are predicted to be involved in EPS production and modification. This work describes the first detailed biochemical and biophysical analysis of EPS from any strain of Mucilaginibacter with unique heavy metal binding properties. The results will be useful for a better understanding of how microorganisms such as M. rubeus P2 adapt to heavy metal polluted environments and how this knowledge can potentially be harnessed in biotechnological applications such as industrial waste water purification, bioremediation of heavy metal contaminated soil and beneficial plant microbe interactions. The toolbox provided in this paper will provide a valuable basis for future studies.

Cytogenetic, Serum Liver Enzymes and Liver Cell Pathology of the Hampala Barb Fish (Hampala macrolepidota) Affected by Toxic Elements in the Contaminated Nam Kok River Near the Sepon Gold-Copper Mine, Lao PDR.

This study aimed to determine toxic element concentrations in aquatic environments, including water and sediment, and in the Hampala macrolepidota fish, and to evaluate chromosome abnormalities, serum liver enzyme changes and liver histopathological alterations in H. macrolepidota from the Nam Kok River near the Sepon gold-copper mine, Lao People’s Democratic Republic, as compared with a control area without mining activity. The results revealed significant differences (p < 0.05) in As, Ba, Cu, Fe, Mn, Ni, Se and Zn in water, in all of the studied potentially toxic elements in sediment, and in As, Ba, Cd, Cr, Cu, Mn, Ni, Se, and Zn in the fish between the study and control areas. A chromosome assessment demonstrated 6 types of chromosome abnormalities, among which centric gap had the highest total number of chromosome abnormalities. Percentage of chromosome abnormalities, percentage of cells with chromosome abnormalities and serum liver enzymes in H. macrolepidota were significantly different (p < 0.05) between the two studied areas and were higher in the contaminated fish than in the control fish. The observation of liver histopathological changes revealed cellular degeneration, such as nuclear damage, abnormal cytoplasmic mitochondria and the disintegration of rough endoplasmic reticulum. The results indicate that the contamination of potentially toxic elements in the Nam Kok River near the Sepon gold-copper mine area negatively affected chromosomes, serum liver enzymes and liver cell structures in H. macrolepidota.

Effects of Contamination by Heavy Metals and Metalloids on Chromosomes, Serum Biochemistry and Histopathology of the Bonylip Barb Fish Near Sepon Gold-Copper Mine, Lao PDR.

The objectives of the present study were to determine the concentrations of heavy metals and metalloids in water, sediment and Osteochilus vittatus fish, and to assess chromosome aberrations, serum biochemical changes and histopathological alterations in O. vittatus from the Nam Kok river near the Sepon gold-copper mine, Lao People’s Democratic Republic compared with the reference area. The results showed that Fe, Mn and Ni in water, As and Cd in sediment as well as As, Cd, Cr, Mn and Ni in O. vittatus muscle samples near the gold-copper mine exceeded standard values. Furthermore, the chromosome assessment in O. vittatus revealed seven types of chromosome aberrations, and the highest total number of chromosome aberrations was a centromere gap. The total number of chromosome aberrations, cell number with chromosome aberrations and percentage of chromosome aberrations in O. vittatus as well as serum liver enzymes between the studied areas were significantly different (p < 0.05). The liver histopathological alterations of the fish near the gold-copper mine revealed atypical cellular structures as nuclear membrane degeneration, rough endoplasmic reticulum disintegration and abnormal cytoplasmic mitochondria. The results of this study suggested that heavy metal and metalloid contaminations from the Sepon gold-copper mine area negatively affect O. vittatus fish in terms of chromosomal defects, serum biochemical changes and liver histopathological appearances.

Practical Experience in Large-Scale Development of Zijinshan Low-Grade Gold-Copper Mine

The Zijinshan gold-copper mine, in spite of the low-grade nature of the ore, has become one of the largest production-scale and most profitable non-ferrous metal mines in China. The successful application of hydrometallurgy as well as proper engineering design are the key factors for large-scale development of the Zijinshan gold-copper mine. In this contribution, the practical experience acquired in the development of the Zijinshan gold and copper mines is summarized. This covers most aspects of the production process including mining, beneficiation, ore stacking, heap (bio)leaching, carbon-in-leach, solvent extraction, electrowinning, wastewater and tailing treatments. The authors believe that this practical experience will not only help to promote the development of hydrometallurgy, but can also serve as a model for other gold and/or copper plants around the world.

A Novel Method to Evaluate the Effect of Slope Blasting under Impact Loading

In this paper, the quantitative evaluation of the explosion effect based on the fuzzy comprehensive evaluation method is proposed to describe the qualitative evaluation results. The selected state characteristic parameters are expressed by two kinds of membership functions, fuzzy normal and triangular distribution membership functions, and preliminary evaluation results are obtained. The validity index of the maximum membership principle is used to assess the accuracy of the evaluation results of two algorithms, and a relevant approaching degree is chosen to optimize the results. The entire evaluation process selects eleven indicators to form an evaluation set, including the boulder yield, root rate, flying distance of flyrock, explosive consumption, postcracking distance, detonator unit consumption, vibration velocity, loose coefficient, cast distance, throw rate, and blasted volume per meter of hole. Part of the indicator parameters are derived from field test monitoring, and another part of the indicator parameters are derived from numerical simulation. The simulation process uses the user-defined material interface function provided by LS-DYNA. And the numerical model of slope blasting is established by embedding the evolution relationship of tensile and compressive damage into the elastoplastic constitutive material. The evaluation method proposed in this paper is used to evaluate the postexplosion effect of Zijin Mountain gold-copper mine slope cast blasting. The results demonstrate that the fuzzy normal distribution membership function can correlate the state characteristic information and evaluation index effectively, and the working condition after explosion can be reflected accurately. Additionally, the influencing factors can be ranked by the importance degrees according to the calculated value of the evaluation index.

Comparative Insights Into the Complete Genome Sequence of Highly Metal Resistant Cupriavidus metallidurans Strain BS1 Isolated From a Gold-Copper Mine.

The highly heavy metal resistant strain Cupriavidus metallidurans BS1 was isolated from the Zijin gold–copper mine in China. This was of particular interest since the extensively studied, closely related strain, C. metallidurans CH34 was shown to not be only highly heavy metal resistant but also able to reduce metal complexes and biomineralizing them into metallic nanoparticles including gold nanoparticles. After isolation, C. metallidurans BS1 was characterized and complete genome sequenced using PacBio and compared to CH34. Many heavy metal resistance determinants were identified and shown to have wide-ranging similarities to those of CH34. However, both BS1 and CH34 displayed extensive genome plasticity, probably responsible for significant differences between those strains. BS1 was shown to contain three prophages, not present in CH34, that appear intact and might be responsible for shifting major heavy metal resistance determinants from plasmid to chromid (CHR2) in C. metallidurans BS1. Surprisingly, the single plasmid – pBS1 (364.4 kbp) of BS1 contains only a single heavy metal resistance determinant, the czc determinant representing RND-type efflux system conferring resistance to cobalt, zinc and cadmium, shown here to be highly similar to that determinant located on pMOL30 in C. metallidurans CH34. However, in BS1 another homologous czc determinant was identified on the chromid, most similar to the czc determinant from pMOL30 in CH34. Other heavy metal resistance determinants such as cnr and chr determinants, located on megaplasmid pMOL28 in CH34, were shown to be adjacent to the czc determinant on chromid (CHR2) in BS1. Additionally, other heavy metal resistance determinants such as pbr, cop, sil, and ars were located on the chromid (CHR2) and not on pBS1 in BS1. A diverse range of genomic rearrangements occurred in this strain, isolated from a habitat of constant exposure to high concentrations of copper, gold and other heavy metals. In contrast, the megaplasmid in BS1 contains mostly genes encoding unknown functions, thus might be more of an evolutionary playground where useful genes could be acquired by horizontal gene transfer and possibly reshuffled to help C. metallidurans BS1 withstand the intense pressure of extreme concentrations of heavy metals in its environment.

Using large-scale geotechnical modelling to solve mining tasks at a gold-copper mine

Map 3D geotechnical software is used at Dundee Precious Metals Chelopech EAD to study and understand the ground conditions prior to commencing any mining works. The mine uses the Long Hole Stoping with Fill mining approach. New production stopes are adjacent either to backfilled stopes or to fault areas. This article discusses large-scale geotechnical modelling of two orebodies with a fault zone between them. It demonstrates the model development method and stages, the stability of the rock mass surrounding the planned stopes by monitoring certain key ground stability parameters. The model of the fault between the two orebodies is run for three scenarios: the first one is a wireframe solid model featuring lower strength and deformation properties and elastic behaviour; the second one is the same as the first one but with elastic/plastic behaviour; and the third one is a surface with zero cohesion, a fraction angle of 25° and elastic behaviour. After solving the model, the locations for installation of Multi-Point Borehole Extensometers (MPBX) are selected to monitor deformations for model verification.

Ecological modelling of a wetland for phytoremediating Cu, Zn and Mn in a gold–copper mine site using Typha domingensis (Poales: Typhaceae) near Orange, NSW, Australia

AbstractAn artificial wetland was computationally modelled using STELLA®, a graphical programming tool for an Au-Cu mine site in Central-west NSW, the aim of which was to offer a predictive analysis of a proposed wetland for Cu, Zn and Mn removal using Typha domingensis as the agent. The model considers the important factors that impact phytoremediation of Cu, Zn and Mn. Simulations were performed to optimise the area of the wetland; concentration of Cu, Zn and Mn released from mine (AMD); and flow rates of water for maximum absorption of the metals. A scenario analysis indicates that at AMD = 0.75mg/L for Cu, Zn and Mn, 12.5, 8.6, and 357.9 kg of Cu, Zn and Mn, respectively, will be assimilated by the wetland in 35 years, which would be equivalent to 61 mg of Cu/kg, 70 mg of Zn/kg and 2,886 mg of Mn/kg of T. domingensis, respectively. However, should Cu, Zn and Mn in AMD increase to 3 mg/L, then 18.6 kg of Cu and 11.8 kg of Zn, respectively, will be assimilated in 35 years, whereas no substantial increase in absorption for Mn would occur. This indicates that 91 mg of Cu, 96 mg of Zn and 2917 mg of Mn will be assimilated for every kg of T. domingensis in the wetland. The best option for Cu storage would be to construct a wetland of 50,000 m2area (AMD = 0.367 mg/L of Cu), which would capture 14.1 kg of Cu in 43 years, eventually releasing only 3.9 kg of Cu downstream. Simulations performed for a WA of 30,000 m2indicate that for AMD = 0.367 mg/L of Zn, the wetland captures 6.2 kg, releasing only 3.5 kg downstream after 43 years; the concentration of Zn in the leachate would be 10.2 kg, making this the most efficient wetland amongst the options considered for phytoremediating Zn. This work will help mine managers and environmental researchers in developing an effective environmental management plan by focusing on phytoremediation, with a view at extracting Cu, Zn and Mn from the contaminated sites.

Aboriginal values and resource development in Native Space: Lessons from British Columbia

In British Columbia, Canada, resource development takes place within the traditional territories of Aboriginal people, often without signed treaties or agreements. This frequently sparks opposition from local Indigenous communities, even in locations where economic benefits are promised in exchange for access to land. This paper casts light on this subject through a case study of resistance among the Tsilhqot’in Indigenous people, who are protesting against the development of a multi-million dollar gold-copper mine within their traditional territory. Drawing on findings from Community-Based research and a review of documents from Tsilhqot’in court cases, this paper provides a deepened understanding about the relationship the Tsilhqot’in people have with their land. The major themes covered are as follows: (1) Aboriginal community values, which are critical to the survival of such people; and (2) the contemporary culture of the Tsilhqot’in people, including profiling how some women continue to survive on the land. The study captures the dynamics of Aboriginal values at the project location and how these are affected by resource development activities.

A New Processing Technology of Comprehensive Utilization on the Gold Copper Ore

The character of one refractory gold copper mine located in the west of the Sichuan province is so complex, that the valuable element of the ore cannot be recovered by the traditional beneficiation processing. In this paper, a series of tests were conducted to optimize the suitable collector and develop a new beneficiation processing to recover the valuable associated minerals as while as the copper minerals. The results of the tests showed that the bulk-concentrate with 14.73% of Cu grade, 40.59×10-6 of Au grade and 2360.00×10-6 of Ag grade can be obtained from the recommended bulk flotation processing. The recommended processing showed in this paper could greatly improve the copper mineral recovery and reduce emissions of copper tailings, which is very important for the copper beneficiation technology development and the protection of the environment.

Resourceful impacts: Harm and valuation of the sacred

The use of rationalized risk assessment to identify the costs and benefits of protecting Aboriginal sacred sites is ubiquitous in Canadian law. Like other contemporary critics of cost-benefit analysis, I voice concerns with its use to adjudicate moral claims and recognize that it can misidentify the depth of loss experienced by Aboriginal peoples when sacred sites are destroyed. Nonetheless, in this article, I question in what ways technocratic approaches to risk could be helpful in protecting sacred sites. The article draws on two recent environmental assessments, the Prosperity Gold-Copper Mine Project in British Columbia and the Screech Lake Uranium Exploration Project in the Northwest Territories, to argue that innovative approaches to characterizing loss illustrate the potential of rationalized methods to identify harm better than it has in the past. The panels’ recommendations to reject the projects, based on the risk that the communities would suffer mental and psychological harm, reflect a genuine effort to provide decision makers with the real cost of approving these two projects. While I do not suggest that cost-benefit analysis can represent the loss of absolute values, I argue that, if done with cultural context in mind, assessment may help to extract the type of information needed to find the depth of empathy from which legal solutions may be constructed.

Accumulation of heavy metals by naturally colonising Typha domingensis (Poales: Typhaceae) in waste-rock dump leachate storage ponds in a gold–copper mine in the central tablelands of New South Wales, Australia

Naturally colonised populations of Typha domingensis in mine waste-rock dump leachate ponds (northern leachate pond [NLP] and southern leachate pond [SLP] and a nearby reference site (Cadiangullong Creek [CAC] were analysed for accumulation of Cu, Mn, and Zn in the winter of 2010 and early autumn of 2011. Concentrations in sediment, leachate and creek water at NLP, SLP, and CAC were also analysed for Cu, Mn, and Zn. Linear regression of Cu, Mn, and Zn concentrations in the leachate at each site revealed a significant reduction in these metals at NLP only in early autumn as leachate travelled away from the toe of the waste-rock dump and through the naturally colonised populations of T. domingensis. This study indicates that this species is a suitable candidate for the process of phytoimmobilisation of the tested metals.

Contents of Al, Cu, Fe, and Mo in Phalaris aquatica and Trifolium subterraneum grown on an unamended and amended gold-mine tailings-storage facility in central-western New South Wales, Australia

Phalaris aquatica and Trifolium subterraneum grown on a tailings-storage facility (control) and tailings-storage treated with either topsoil or biosolids in a gold–copper mine were analysed for Al, Cu, Fe, and Mo contents. Soil samples from the treatments were also tested for these metals and soil properties. Results indicated that higher levels of metals occurred in T. subterraneum than in P. aquatica; metal contents in both taxa were significantly greater in the control, and higher metal contents occurred in plants tested in May 2008 (autumn) compared with October 2008 (spring). A strong relationship existed between Cu, Fe, and Mo contents in T. subterraneum and Al content in the tested soils. A significant relationship was also observed between Al content in T. subterraneum and K, Na, and SO4 levels in the soils. We recommend that tailings soil be amended with either topsoil or biosolids before grazing livestock to reduce the risk of either mineral deficiencies or toxicities.