Mill Discharge Research Articles

Ddetermination of bond work index of Bagega gold mineral deposit of Zamfara State, Nigeria

The study determined the bond work index of Begaga gold mineral deposit of Zamfara State Nigeria using Berry and Bruce modified bond method. Sample of gold mineral was sourced using random sampling method. Reference mineral (Granite) of known weight and work index of 15.13Kwh/ton was ground for thirty minutes at a particular speed and power consumed was determined from the power rating of the ball mill. An identical weight of Bagega gold mineral whose work index was to be determined was ground in the same ball mill under same condition as that of reference mineral. Size analysis of the ball mill under same condition as that of the reference mineral was performed. Size analysis of the ball mill feed and discharge for both ores was carried out and 80% passing particle size of the ball mill feed and discharge for the two ores were estimated mathematically using correlation approach. The work index of the Bagega gold mineral was determined by equating the power consumed in the two indexes of the ore. It was found to be approximately 14.24Kwh/ton which is within the acceptable range of 10 - 15.14Kwh/ton indicated in literatures as standard work index range of gold. This value of the work index means that 14.25Kilowatts hour of energy is required to reduced one tonne of the gold ore from 80% passing particle size of 1117.32μm to 80% passing particle size of 800.00μm, it should serve as the work index of Bagega gold.

Acoustic Sensing of Fresh Feed Disturbances in a Locked-Cycle Laboratory AG/SAG Mill

In a large-scale operation, feed ores are introduced into the AG/SAG mill in a continuous mode at a given flow rate to replace the discharging slurry. Nonetheless, the variations in the feed characteristics, typically hardness and size distribution, could cause sudden disruption to the mill operation. This would be challenging to detect in practice, owing to the hostile environment of the mill. In this work, an acoustic sensing-based monitoring technique was utilized in a laboratory-scale AG/SAG mill locked-cycle study to keep track of fluctuations caused by feed ore heterogeneity. Analysis of the recorded mill acoustic response using statistical root mean square (RMS) and mill discharge sizes showed that the introduction of fresh feed with varying hardness and size distribution considerably altered the mill product undersize of −150 μm and acoustic emission. Overall, the acoustic sensing technique demonstrated that the AG/SAG mill stability as well as disturbances caused by different feed size fractions and hardness can be monitored using the mill acoustic response, an indication of real-time monitoring and optimisation.

Influence of Water Quality on Sulphide Ore Oxidation and Speciation of Sulphur Anions during Autogenous Milling

Earlier studies at the Kevitsa Cu-Ni concentrator plant have indicated that seasonal variations of the properties of the process water affect the oxidation of the surface of the minerals, and further, the pentlandite flotation performance. However, it is not clear whether the differences in flotation performance are solely due to changes in the mineral surface oxidation, and/or also due to surface oxidation-induced changes in the aqueous phase of the pulp. This paper investigates the effects of the mineral surface oxidation of Kevitsa Cu-Ni ore on the properties of the aqueous phase of the slurry. A systematic study was formulated to monitor the surface oxidation related changes in the mill circuit of the Kevitsa concentrator plant. The study was timed to coincide with a seasonally observed drop in the concentrator plant’s flotation performance, which happens during the summer months (June, July, and August). Both physicochemical parameters, as well as sulphur oxyanions in the plant process water, mill discharge, and hydrocyclone overflows were monitored. Also, the bubble size in selected rougher and cleaner cells was monitored. The results show that season-related changes in mineral surface oxidation cause clear differences in the aqueous phase chemistry of the mill circuit. The increased concentration of reduced sulphur species in the mill discharge is an indication of extensive oxidation of the ore during milling. Also, the bubble size of the flotation cells reacts to the observed seasonal change. The findings of the study confirm that the consequences expected, based on the theory of mineral surface oxidation, are observable downstream in the aqueous phase of the milling circuit. Based on these results, it is not yet possible to say whether the poor flotation performance is caused solely by the oxidation of the mineral surface or also by the properties of the aqueous phase of the slurry after milling. However, the results show that the plant needs both to find ways to limit oxidation rates in the summer, and to consider installing a more robust frother, capable of maintaining efficacy during the warm season. The findings of this study may help the plant to develop ways to enable a timely response to changes in the recycled process water quality, to prevent harmful impacts on pentlandite flotation. The former could be achieved by lowering the temperature of the process water and flotation air, whereas the latter could mean using a different frother.

Determination of Work Index of Muro Iron Ore Using Marble and Granite as Reference Ores

The work index of Muro iron ore was determined using the modified Bond’s method also known as Berry and Bruce method. This study used iron ore obtained from Muro town, a community in Toto LGA, Nasarawa state as the test ore. Marble and Granite which was separately used as the reference ores were obtained from Muro environs. 100 g each of the test ore and the reference ores were subjected to the same grinding conditions in a ball mill. Size analysis of the feed to the ball mill and the product of the ball mill for both test ore and reference ores were carried out and the results tabulated accordingly. The 80% passing particle size of the ball mill feed and discharge for the samples were calculated using the Gaudian Schumann expression. The Bond’s equation was then used to calculate the work index of the Muro iron ore which was found to be 24.84 kWh/ t when marble was used as reference ore and 27.41 kWh/ t when granite was used as reference ore. The average work index of Muro iron ore was calculated as 26.13 kWh/ t, while the energy requirement for grinding the ore was found to be 3.62 kWh/ t. The value of the work index of Muro iron ore is within the limit of work index of iron ore quoted in literatures

Amelioration of disulfonated Acid Red and hexavalent chromium phytotoxic effects on Triticum aestivum using bioremediating and plant growth-promoting Klebsiella pneumoniae SK1

Bacterial strain identified as Klebsiella pneumoniae SK1, based on 16S rDNA sequence study, was isolated from a textile mill discharge point at Dada Nagar industrial area in Kanpur, India in media containing 100 µg/ml each of disulfonated azo dye Acid Red 249 (AR) and hexavalent chromium [Cr(VI)]. SK1 is efficient in the concomitant decolorization and reduction of 100 µg/ml toxic AR and Cr(VI) respectively in 48 h under microaerophilic conditions. The efficacy of AR decolorization was found to be preeminent in static conditions, 37°C, 2-4% salinity and 7-9 pH range. 99% decolorization for initial AR concentration of 100 µg/ml in 48 h, and 91% for 250 µg/ml and 77% for 500 µg/ml was recorded in 72 h respectively in the presence of 100 µg/ml Cr(VI). Significant reductive changes in spectroscopic absorption spectra were observed for SK1 treated AR+Cr(VI) amended media with respect to controls. FITR spectroscopy was used to ascertain the breakage of the azo dye bond and the formation of biodegradative metabolites. Additionally, SK1 was found to be positive for indole acetic acid, ammonia, phosphate and potassium solubilization and biofilm formation. In plant bioassay, in vitro SK1 treated AR+Cr(VI) TSB media was used to treat Triticum aestivum in the soil environment. In comparison to untreated control, plants treated with bioremediation media shows increased percent germination, root and shoot length with a complete reversal of phytotoxic effects of the AR+Cr(VI) treated plants. In this study, environmental K. pneumoniae SK1 shows concomitant azo dye and Cr(VI) remediation with plant growth-promoting activity.

Strengthening liberation and separation of magnetite ore via magnetic pulse pretreatment: An industrial test study

Performing ore pretreatment before grinding is particularly crucial for improving mineral liberation and conserving energy. This study proposed an innovative magnetic pulse pretreatment (MPP) technology that primarily used the magnetostrictive effect in an alternating magnetic field to enhance mineral liberation. The effect of MPP on the liberation degree and magnetite separation for magnetite ore were systematically investigated. The results show that the size and volume of the magnetic mineral particles in the ore due to the stretching effect of the alternating magnetic field resulted in microcracks at the interface between different minerals. Compared with the unpretreated process in an industrial test, increment in the −0.043 mm content of the ball mill discharge increased by 3.33 percentage points, increment in the liberation degree of magnetite across the entire particle size range increased by 5.82 percentage points, and increment in the iron concentrate grade increased by 1.22 percentage points, with an error range of 0.1%, due to MPP. The industrial application of MPP brings an enormous economic benefit potential to iron ore utilization.

Determination of work index of graphite from Samanburkono (Nigeria) using modified bond's method

This report covers the work index determination of Saman-Burkono graphite. The test sample was obtained from Saman-Burkono in Ningi Local Government Area of Bauchi state, while reference material (coal) was sourced from Okaba coal mine, Ankpa Local Government Area of Kogi State. A known weight of graphite sample and coal were crushed, pulverized and ground using the laboratory milling machine. The two samples were grinded with two cells of diameter 3.5cm and 222g weight. The analysis of the feed size fort the two samples was found graphically to be 180?m and 175?m, and ball mill discharge was 130?m and 140?m respectively. The work index of a coal as reference material was 7.65 kWh/ short ton, this was used to calculate the work index of the graphite which was found to be 11.047 kWh/short ton, being the required energy to comminute one ton of graphite. http://dx.doi.org/10.4314/njt.v38i3.10

Spatial and temporal patterns of diatom assemblages, and their drivers, in four US streams: evidence from a long-term dataset

Bioassessment to evaluate stream integrity and determine changes related to point-source discharges is typically focused in wadeable streams, with limited understanding of seasonal and annual variation. We used a multi-year (n = 13), multi-site (n = 5–7), seasonally (spring and fall) sampled dataset to evaluate spatial and temporal patterns in diatom assemblages relative to measured environmental variables, land use, and pulp and paper mill discharges in a wadeable stream (Codorus Creek, PA) and three non-wadeable rivers (Leaf River, MS; McKenzie and Willamette rivers, OR). Analysis of variance (ANOVA) and permutational ANOVA (PERMANOVA) showed that significant spatial differences in commonly used diatom biotic integrity/diagnostic metrics and assemblage structure were common in the wadeable stream, but rare in the non-wadeable rivers. Season-specific diatom patterns were observed in all streams regardless of size, but annual variation was more prevalent in the non-wadeable rivers. Environmental variables explained 35–58% of the variability in diatoms in the spring and 33–50% in the fall, with physical habitat characteristics associated with stream morphology and seasonality more important than those associated with anthropogenic inputs such as land use and point sources. Findings from this study highlight the value of spatially and temporally comprehensive datasets in understanding and interpreting diatom assemblage patterns.

Analysis of POME Discharge Quality from Different Mill in Perak, Malaysia: A case study

Palm oil mill effluent (POME) is a major concern of oil palm mill because it contributes to numerous pollution such as soil, water and air pollution. In order to maintain a clean environment for a sustainable agricultural system in oil palm plantation, the quality of POME and its level must be monitored to ensure that the requirement set by the country is met. Hence, this paper is written based on the data of POME final discharge into waterways taken from Malaysian Department of Environment in four regions of Perak, Malaysia. The data is compared between regions and relatively different levels of discharge have been produced. Some of the mills produce final POME wastewater above the limit that has been set. The remaining mills discharge the wastewater below the maximum allowed level. This is an indicator that each mill has its own Standard of Procedures in treating POME before being discharged into waterways. It is suggested that the mills take a proactive approach to treat POME beyond the ponding system. POME can be physically processed to produce biofertilizer and biocompost for organic farming. The mills apply phytoremediation techniques in treating POME to reduce the unwanted variables that can affect the sustainability of our environment.

Cardiovascular dysfunction and oxidative stress following human contamination by fluoride along with environmental xenobiotics (Cd & Pb) in the phosphate treatment area of Togo, West Africa

In Togo, the phosphate ore mill discharges waste containing xenobiotics like cadmium, lead and fluoride. If the role of heavy metals in the appearance of pathologies is known, the role of fluoride remains to be studied alongside xenobiotics. This study tested the hypothesis that the toxicity of fluoride contributes, along with heavy metals, to physiological dysfunction. In this process, we have studied the variation in the parameters of cardiovascular functioning, depending on the level of human contamination by fluoride and xenobiotics. The concentration of Cd and Pb in blood samples were determined by AAS and fluoride by titanium-chloride method. Lipid peroxidation, the total antioxidant potential of collected blood samples and the parameters of cardiovascular dysfunction were also measured. Cd, Pb and F contents and lipid peroxidation were found to be significantly elevated in polluted areas than control zone as well as total cholesterol, LDL and triglyceride. HDL and antioxidant potential of blood decreased in the polluted areas. Correlation tests showed that fluoride levels are related to variations in the bio-indicators of high blood pressure and oxidative stress (R varied from 0.354 to 0.907). Togo phosphate treatment leads to human contamination with fluoride, along with Cd and Pb, increasing the risk of cardiovascular dysfunction and oxidative stress.

Assessing wild fish exposure to ligands for sex steroid receptors from pulp and paper mill effluents in the Biobio River Basin, Central Chile

Bioactive substances in the Biobio River Basin in Chile were examined by deploying Semi Permeable Membrane Devices (SPMDs) upstream and downstream of 4 pulp mill effluent discharges. Androgenic and estrogenic activity of SPMD extracts were then evaluated using in vitro fish sex steroid receptor binding assays. The results indicated the occurrence of estrogenic type compounds associated with one of the mill discharges. A significant correlation among the presence of these compounds, an increase in gonadosomatic index GSI and induction of hepatic EROD activity of two native fish species was observed. However, no significant presence of mature oocytes in female gonads was detected. Although EROD induction was observed in sites impacted by mill effluents, an increase of its activity occurred towards the downstream areas, suggesting other non-mill sources. More research is needed to understand the environmental changes in context of the new technological improvements in treatment systems to MBBR (Moving Bed Biofilm Reactor) recently implemented by the pulp mill industries.

Correlation between the hydrogen peroxide formed during grinding and the oxidized species present on the surface of sphalerite

Flotation separation of sphalerite from chalcopyrite is significantly affected by the oxidation of metal species on the surface of sphalerite, partially contributed by production of the reactive oxygen species hydrogen peroxide (H2O2) and hydroxyl radicals (OH) if any during wet grinding of a complex sulphide ore. This research experimentally measures the production of H2O2 during grinding of a Cu/Zn ore from Mine Matagami (Canada) with different grinding time and in different grinding environments. Results reveal that H2O2 was formed spontaneously when the ore was ground in the ball mill. The amount of H2O2 generated increases with an increased pyrite load to the ball mill. Grinding with mild steel shows a lower measurable concentration of H2O2 in slurry relative to grinding with stainless steel balls. This appears to be in conflict with other researchers. It is found that Fe ions released from mild steel balls benefits the conversion from H2O2 to (OH), but in the current H2O2 detection program hydroxyl radicals (OH) could not be measured. Surface analysis of mineral grains from the mill discharge samples has identified an obvious correlation between H2O2 detected in the pulp and sphalerite surface oxidation. Lower pulp H2O2 concentrations possibly correspond to the conversion of H2O2 to OH which may be linked to a more pronounced sphalerite surface oxidation.

Spatial and Temporal Variation of Parameters in Wadi Andlou, Tunisia‐Pollution by Pulp Mill Discharge

This study evaluated space‐time variation of water quality data sets for the Wadi Andlou Kasserine, Tunisia, using multivariate analytical techniques including cluster analysis, principal component analysis (PCA) and correlation analysis (CA). The present study showed that values of temperature (T), electrical conductivity (EC), biochemical oxygen demand (BOD), chemical oxygen demand (COD), chloride, phosphate, sulfate, fecal coliform, Streptococcus, Salmonella spp., and Enterococci were significantly higher in the dry season compared to samples taken in the wet season. Concurrently, pH, dissolved oxygen (DO), turbidity, suspended matter (SM), presented values significantly lower in dry season than surveys in rainy season. The following parameters BOD5, COD, , Cl−, SM, Salmonella spp. did not meet the Tunisian standard NT 106 for surface water quality. Analysis of pollutant concentrations via PCA showed that the two first components accounted for 87.34 and 93.17% of the total variance for dry and rainy season sampling, respectively. The first component included T, pH, EC, SM, , Cl−, , turbidity, COD, BOD, , Enterococci, fecal coliform and streptococcus, Salmonella spp., and total bacteria. The second included DO and . Cluster analysis identified the five sampling sites into three groups in the rainy and dry season based on seasonal differences and various pollution levels caused by physicochemical and bacteriological properties. The results suggest that future monitoring can include fewer sampling sites, and stratified random sampling plans can save time and resources.

A ToF‐SIMS investigation on correlation between grinding environments and sphalerite surface chemistry: implications for mineral selectivity in flotation

AbstractChanges in mineral surface properties during grinding play a key role in flotation performance. Time of flight secondary mass spectrometry (ToF‐SIMS) surface chemical analytical studies have shown that flotation separation of sphalerite from chalcopyrite is significantly affected by the oxidation of metal species on the surface of sphalerite. The intensity of iron oxyhydroxyl species on the surface of sphalerite has a positive correlation with poor recovery of sphalerite. Given the link between the presence of oxide species on the surface of sphalerite and a lower recovery during copper flotation, a laboratory study was initiated to evaluate the potential for sphalerite surface oxidation control and improving recovery through grinding. For the investigation, a ball mill that allowed for monitoring pulp chemistry during grinding was utilized to study the impact of grinding conditions on selective flotation of sphalerite. ToF‐SIMS was used to identify and measure the variability in sphalerite surface species as a result of the different test parameters. Variable mill parameters include two types of grinding media, aeration conditions, addition of FeSO4, and altering the pyrite content in the feed ore. ToF‐SIMS analyses of mill discharge samples identified higher intensities of iron oxyhydroxyl species on sphalerite surface subsequent to grinding with mild steel balls, in condition of aeration, use of FeSO4, and by increasing the pyrite content of the feed ore. The higher adsorption of iron oxyhydroxyl species on the surface of sphalerite should be consistent with the lower recovery. To verify this, bench‐scale flotation tests in the presence and absence of FeSO4 were performed; results correlated iron oxyhydroxyl species with the poor sphalerite recovery. Copyright © 2017 John Wiley & Sons, Ltd.

Investigation of laboratory conditions effect on prediction accuracy of size distribution of industrial ball mill discharge by using a perfect mixing model. A case study: Ozdogu copper-molybdenum plant

Investigation of laboratory conditions effect on prediction accuracy of size distribution of industrial ball mill discharge by using a perfect mixing model. A case study: Ozdogu copper-molybdenum plant

Efecto de las descargas domésticas y de beneficio de café sobre la calidad del agua y la diversidad de larvas de Odonata (Insecta) en un arroyo de bosque mesófilo de montaña en Veracruz, México

Two contrasting sites along Huehueyapan River (Veracruz, Mexico), one relatively conserved and the other one impacted by domestic and coffee mill discharges, were compared based on water quality data, and the structure of the Odonata larval assemblages. Riparian vegetation of both sites was differentially modified or replaced. Physical and chemical parameters and Odonata larvae were gathered from January to November 2001. A Hotelling-T test was used to compare the physico-chemical parameters while rank/abundance graphs and Renyi diversity profiles were constructed using Odonata larvae data. A total of 2,212 larvae of 13 species in 7 genera were collected. The sites were very similar in number of species and Odonata larval assemblage structure, however, some of the most abundant species at both sites showed significant differences in abundance. The observed differences between the 2 sites are mainly explained by differences in the structure of riparian vegetation and the availability of substrates for odonates and, secondarily, by physical and chemical changes in the water. An abundance ratio was established based on the most abundant species for monitoring future impairment or recovery changes.

Combined DEM and SPH simulation of overflow ball mill discharge and trommel flow

Discharge of finer rock, pebbles, ball scats and slurry from mills and its flow through trommels and into other processing operations all affect the performance of overflow ball mills. Modelling of the coarser rock components and the grinding media is best done using the Discrete Element Method (DEM) while modelling of the slurry component is best done using a compatible particle method such as SPH (Smoothed Particle Hydrodynamics). This combination of methods allows both these critical components and their interactions to be included in flow models for the mill and discharge arrangements. Information from such models can be used to both understand the flows in these typically closed and data poor environments and to help optimise designs for improved performance and superior wear life. In this paper, a typical discharge/trommel arrangement for an overflow ball mill is analysed using this modelling approach with opportunities for use in process improvement discussed. In the mill grinding chamber the addition of slurry was found to lower the charge shoulder and toe positions due to drag forces on the media, as well as produce a large slurry pool above the toe. Slurry surging out of the grinding chamber carries mill product as well as a small amount of balls through the trunnion and into the trommel for classification. The trunnion spiral was found to be very effective at collecting and returning balls back into the mill grinding chamber. The rate of balls flowing into the trommel was found to be size-dependent favouring the discharge of smaller worn scats for removal as waste. Trommels with and without baffles were compared to establish linkages between transport and classification performance and trommel geometry. The inclusion of baffles inside the trommel was found to spread the slurry sideways and axially and provide improved screening characteristics.

An EKF observer to estimate semi-autogenous grinding mill hold-ups

A non-linear observer model of a semi-autogenous grinding mill is developed. The observer model distinguishes between the volumetric hold-up of water, solids, and the grinding media in the mill. Solids refer to all ore small enough to discharge through the end-discharge grate, and grinding media refers to the rocks and steel balls. The rocks are all ore too large to discharge from the mill. The observer model uses the accumulation rate of solids and the mill's discharge rate as parameters. It is shown that with mill discharge flow-rate, discharge density, and volumetric hold-up measurements, the model states and parameters are linearly observable. Although instrumentation at the mill discharge is not yet included in industrial circuits because of space restrictions, this study motivates the benefits to be gained from including such instrumentation. An extended Kalman filter is applied in simulation to estimate the model states and parameters from data generated by a semi-autogenous mill simulation model from literature. Results indicate that if sufficiently accurate measurements are available, especially at the discharge of the mill, it is possible to reliably estimate grinding media, solids and water hold-ups within the mill. Such an observer can be used as part of an advanced process control strategy.

Measurement and modeling of residence time distribution of overflow ball mill in continuous closed circuit

Comparison between anticipated and measured mean residence time (MRT) along with analysis of the shape of residence time distribution (RTD) curves provides the most useful and valid information about mixing properties within a ball mill operating at industrial scale. In this work, the RTD measurements were carried out for a primary ball mill in closed circuit with hydrocyclones at two feed rates (i.e., 280 and 230 tons per hour (t/h)) by means of tracer technique. Also, perfect mixer, N-Mixer, and Weller models were studied to describe the RTD curves. It was found that the mixing condition inside the ball mill was very far from the perfect mixing circumstance. While, N-perfect mixer in series (N-Mixer model) showed better results compared to the large and small tanks in series (Weller model). According to the obtained results of the N-Mixer RTD model, when the ball mill throughput was enhanced from 230 t/h to 280 t/h, the MRT was decreased from 9.92 to 7.39 min, respectively. Moreover, relative variance of N-Mixer model diminished approximately 18% and particle cumulative passing from 75 μm of ball mill discharge increased 9%. Finally, it was concluded that operating in over-filled condition and poor mixing circumstance of slurry were the main reasons of low grinding efficiency.

An integrated approach for identifying priority contaminant in the Great Lakes Basin - Investigations in the Lower Green Bay/Fox River and Milwaukee Estuary areas of concern.

Environmental assessment of complex mixtures typically requires integration of chemical and biological measurements. This study demonstrates the use of a combination of instrumental chemical analyses, effects-based monitoring, and bio-effects prediction approaches to help identify potential hazards and priority contaminants in two Great Lakes Areas of Concern (AOCs), the Lower Green Bay/Fox River located near Green Bay, WI, USA and the Milwaukee Estuary, located near Milwaukee, WI, USA. Fathead minnows were caged at four sites within each AOC (eight sites total). Following 4d of in situ exposure, tissues and biofluids were sampled and used for targeted biological effects analyses. Additionally, 4d composite water samples were collected concurrently at each caged fish site and analyzed for 132 analytes as well as evaluated for total estrogenic and androgenic activity using cell-based bioassays. Of the analytes examined, 75 were detected in composite samples from at least one site. Based on multiple analyses, one site in the East River and another site near a paper mill discharge in the Lower Green Bay/Fox River AOC, were prioritized due to their estrogenic and androgenic activity, respectively. The water samples from other sites generally did not exhibit significant estrogenic or androgenic activity, nor was there evidence for endocrine disruption in the fish exposed at these sites as indicated by the lack of alterations in ex vivo steroid production, circulating steroid concentrations, or vitellogenin mRNA expression in males. Induction of hepatic cyp1a mRNA expression was detected at several sites, suggesting the presence of chemicals that activate the aryl hydrocarbon receptor. To expand the scope beyond targeted investigation of endpoints selected a priori, several bio-effects prediction approaches were employed to identify other potentially disturbed biological pathways and related chemical constituents that may warrant future monitoring at these sites. For example, several chemicals such as diethylphthalate and naphthalene, and genes and related pathways, such as cholinergic receptor muscarinic 3 (CHRM3), estrogen receptor alpha1 (esr1), chemokine ligand 10 protein (CXCL10), tumor protein p53 (p53), and monoamine oxidase B (Maob), were identified as candidates for future assessments at these AOCs. Overall, this study demonstrates that a better prioritization of contaminants and associated hazards can be achieved through integrated evaluation of multiple lines of evidence. Such prioritization can guide more comprehensive follow-up risk assessment efforts.