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PubMed2004

Geochemical characterization of acid mine drainage from a waste rock pile, Mine Doyon, Québec, Canada.

Water quality in the unsaturated and saturated zones of a waste rock pile containing sulphides was investigated. The main objectives of the project were (1) the evaluation of geochemical trends including the acid mine drainage (AMD)-buffering mechanism and the role of secondary minerals, and (2) the investigation of the use of stable isotopes for the interpretation of physical and geochemical processes in waste rock. Pore water in unsaturated zone was sampled from suction lysimeters and with piezometers in underlying saturated rocks. The investigation revealed strong temporal (dry period vs. recharge period), and spatial (slope vs. central region of pile) variability in the formation of acid mine drainage. The main secondary minerals observed were gypsum and jarosite. There was a higher concentration of gypsum in solid phase at Site TBT than at Site 6, suggesting that part of the gypsum formed at Site 6 in the early stage of AMD has been already dissolved. Formation of secondary minerals contributed to the formation of AMD by opening of foliation planes in waste rock, thus increasing the access of oxidants like O2 and Fe3+ to previously encapsulated pyrite. The behavior of several dissolved species such as Mg, Al, and Fe2+ can be considered as conservative in the leachate. Stable isotopes, deuterium and 18O, indicated internal evaporation within the pile, and were used to trace recharge pulses from snowmelt. Isotope trends for 34S and 18O(SO4) indicated a lack of sulfate reduction and zones of active oxidation of pyrite, respectively. Results of numerical modeling of pyrite oxidation and gas and water transport were consistent with geochemical and isotopic trends and confirmed zones of high evaporation rate within the rock pile close to the slope. The results indicate that physical and chemical processes within the pile are strongly coupled and cannot be considered separately when oxidation rates are high and influence gas transport as a result of heat generation.

Environmental Monitoring↗
PubMed2006

Cultivation-dependent and cultivation-independent characterization of the microbial community in acid mine drainage associated with acidic Pb/Zn mine tailings at Lechang, Guangdong, China.

Cultivation-based and molecular approaches were used to characterize the phylogenetic composition and structure of the microbial community in an extremely acidic (pH 2.0) acid mine drainage (AMD) associated with Pb/Zn mine tailings that were undergoing vigorous acid generation. Acidophilic bacteria were isolated and enumerated on solid media, and were found to be restricted to isolates related to Acidithiobacillus ferrooxidans and Acidiphilium cryptum. By contrast, cloning and phylogenetic analysis of 16S rRNA genes revealed that, although low in total taxonomically distinct groups, the tailings AMD ecosystem harbored a wide range of phylogenetically diverse microbes. Of the 141 clones examined, 104 were phylogenetically affiliated with the recently discovered, iron-oxidizing Leptospirillum group III within the Nitrospira. It thus appears that iron serves as the major electron donor in this habitat. Thirty clones were affiliated with the Proteobacteria, half of which belonged to organisms related to Alphaproteobacteria species capable of ferric iron reduction. Other clones were grouped with Betaproteobacteria and Gammaproteobacteria (six clones each), and even with Deltaproteobacteria (three clones), a subdivision with anaerobic sulfate or metal (iron) reduction as the predominant physiological trait of its members. Finally, four clones were clustered within the Firmicutes and the Acidobacteria. Approximately half of the sequence types representing the majority of the total clones fell into lineages that are poorly represented by cultured organisms or have thus far been represented by only a few environmental sequences. Thus, the present study extends our knowledge of the biodiversity of microorganisms populating highly acidic AMD environments.

Bacteria↗
PubMed1992

[Study on the incidence of coal mine pneumoconiosis and lung cancer in Beijing coal mining district].

Thirty-two cases (20.13%) of primary lung cancer from 159 coal miner autopsies of Beijing coal mining area are reported in this study. The ratio of peripheral type to central type of lung cancer is 1.9:1; among them the adenocarcinoma is the most frequent (56.25%). Pathological examination shows that the diffuse interstitial type is the most common lung cancer. The occurrence of adenocarcinoma and the degree of lung fibrosis is related. The average number of ferruginous bodies is 190.2 +/- 8.06 in adenocarcinoma, 165.4 +/- 2.60 in squamous carcinoma, the difference is statistically significant (P < 0.05). The amount of trace elements-Fe, Al, Al/Si and Zn/Cu in lung with cancer is less than that without cancer. This article also discusses the relationship between coal mine pneumoconiosis with lung cancer of the formation of ferruginous bodies in the lung tissue of coal miner autopsies, which resembles the lung cancer combined with asbestosis. We also discussed the carcinogenesis of trace element in lung.

Adenocarcinoma↗
PubMed1983

[The "Mining Rescue System and Mine Fires" Working Group. Tasks, results, future activities].

The president of the working party presents details of its principal tasks in the past and in the present time. These can be summed up in a study of the problems mentioned below and the subsequent elaboration of recommendations for the benefit of the governments, guidelines, information reports and research proposals. The principal problems that were or are still under study are: --prevention of fires: shaft equipment, hydraulic fluids, belt conveyors, . . .; --detection of mine fires and spontaneous combustion; --fighting of mine fires: shaft fires, construction of stoppings, openings and recovering of fire zones, . . .; --coordination and rescue equipment: escape and rescue breathing apparatus, flameproof clothing, rescue of trapped miners; --stabilization of ventilation in the event of fire, . . . The speaker stresses the importance of the information exchange and the atmosphere of fellowship and solidarity that prevails in the working party.

Belgium↗
PubMed2006

A Consensus Data Mining secondary structure prediction by combining GOR V and Fragment Database Mining.

The major aim of tertiary structure prediction is to obtain protein models with the highest possible accuracy. Fold recognition, homology modeling, and de novo prediction methods typically use predicted secondary structures as input, and all of these methods may significantly benefit from more accurate secondary structure predictions. Although there are many different secondary structure prediction methods available in the literature, their cross-validated prediction accuracy is generally <80%. In order to increase the prediction accuracy, we developed a novel hybrid algorithm called Consensus Data Mining (CDM) that combines our two previous successful methods: (1) Fragment Database Mining (FDM), which exploits the Protein Data Bank structures, and (2) GOR V, which is based on information theory, Bayesian statistics, and multiple sequence alignments (MSA). In CDM, the target sequence is dissected into smaller fragments that are compared with fragments obtained from related sequences in the PDB. For fragments with a sequence identity above a certain sequence identity threshold, the FDM method is applied for the prediction. The remainder of the fragments are predicted by GOR V. The results of the CDM are provided as a function of the upper sequence identities of aligned fragments and the sequence identity threshold. We observe that the value 50% is the optimum sequence identity threshold, and that the accuracy of the CDM method measured by Q(3) ranges from 67.5% to 93.2%, depending on the availability of known structural fragments with sufficiently high sequence identity. As the Protein Data Bank grows, it is anticipated that this consensus method will improve because it will rely more upon the structural fragments.

Algorithms↗
PubMed2004

Characterization of iron- and sulphide mineral-oxidizing moderately thermophilic acidophilic bacteria from an Indonesian auto-heating copper mine waste heap and a deep South African gold mine.

Iron- and chalcopyrite-oxidizing enrichment cultures were obtained at 50 degrees C from acidic, high-temperature, copper/gold mine environments in Indonesia and South Africa. Over 90% copper yield was obtained from chalcopyrite concentrate with the Indonesian enrichment in 3 months with 2% solids concentration, when pH was maintained at around 2. Neither addition of silver cations nor an enhanced nutrient concentration influenced chalcopyrite leaching. Excision and sequencing of bands from denaturing gradient gel electrophoresis of the amplified partial 16S rRNA gene showed that the enrichment cultures from different environments in South Africa and Indonesia were very simple, and similar. Chalcopyrite concentrate supported a simpler and different community than Fe2+. The members of the enrichment cultures were closely related to Sulfobacillus yellowstonensis and Sulfobacillus acidophilus.

Bacteria↗
PubMed2006

Ecological health assessment and remediation of the stream impacted by acid mine drainage of the Gwangyang mine area.

Ecological health in a temperate stream impacted by acid mine drainage (AMD) was evaluated by using a multimetric approach of the Index of Biological Integrity (IBI) based on natural fish assemblage. Recently, this approach has been widely used in many developed countries as a tool for ecological risk assessments of water environments. We used 10 metric systems, instead of 12 metrics suggested by Barbour, M. T., Gerritsen, J., Snyder, B. D., & Stribling, J. B. (1999). Rapid Bioassessment Protocols for Use in Streams and Wadeable Rivers: Periphyton, benthic Macroinvertebrates and Fish, 2nd edn. EPA 841-B-99-002. Washington, DC: U.S. Environmental Protection Agency, Office of Water, for a development of the regional IBI model, and used trophic guilds, habitat guilds, and richness variables for the calculation of IBI values. In the model, the attributes of four of 11 metrics were modified for the regional application. IBI values in the stream averaged 20.6 (n = 5), indicating a "poor condition" in terms of ecological health according to the modified criteria of U.S. EPA (1993). Fish Field and Laboratory Methods for Evaluating the Biological Integrity of Surface Waters. EPA 600-R-92-111. Environmental Monitoring systems Laboratory - Cincinnati office of Modeling, Monitoring systems, and quality assurance Office of Research Development, U.S. EPA, Cincinnati, Ohio, 45268. In particular, mean IBI values in the impacted areas of sites 2 and 3 were 13, and this health condition was categorized as "very poor condition." IBI values in the impacted sites were significantly lower than the values found in the control. Also, we found that fishes in site sites 2 and 3 were not present during the study, and morphological deformity of Rhynchocypris oxycephalus was observed in site 4, influenced directly by sites 2 and 3, indicating a chemical impact in the sites. From the results of experiments in which AMD was treated with marine shells at stagnant condition, pH increased up to 6.0 from 3.1, and Fe and Al were removed up to 99% within 6 h. In the reactor experiment considering field application, pH of effluent maintained around 7.0. In addition, concentrations of Fe, Al, and heavy metals decreased remarkably in the effluents, and bottom-opened screen between neutralizer basins showed high effectiveness in the treatment of AMD.

Acids↗
PubMed2005

Microbiology of a wetland ecosystem constructed to remediate mine drainage from a heavy metal mine.

A pilot passive treatment plant (PPTP) was constructed to evaluate the potential of a composite wetland system to remediate acidic, metal-rich water draining the former Wheal Jane tin, in Cornwall, England. The treatment plant consists of three separate and controllable composite systems, each of which comprises a series of aerobic wetlands for iron oxidation and precipitation, a compost bioreactor for removing chalcophilic metals and to generate alkalinity, and rock filter ponds for removing soluble manganese and organic carbon. To understand the roles of microorganisms in remediating acid mine drainage (AMD) in constructed wetland ecosystems, populations of different groups of cultivatable acidophilic microbes in the various components of the Wheal Jane PPTP were enumerated over a 30-month period. Initially, moderately acidophilic iron-oxidising bacteria (related to Halothiobacillus neapolitanus) were found to be the major cultivatable microorganisms present in the untreated AMD, though later heterotrophic acidophiles emerged as the dominant group, on a numerical basis. Culturable microbes in the surface waters and sediments of the aerobic wetlands were similarly dominated by heterotrophic acidophiles, though both moderately and extremely acidophilic iron-oxidising bacteria were also present in significant numbers. The dominant microbial isolate in waters draining the anaerobic compost bioreactors was an iron- and sulfur-oxidising moderate acidophile that was closely related to Thiomonas intermedia. The acidophiles enumerated at the Wheal Jane PPTP accounted for 1% to 25% of the total microbial population. Phylogenetic analysis of 14 isolates from various components of the Wheal Jane PPTP showed that, whilst many of these bacteria were commonly encountered acidophiles, some of these had not been previously encountered in AMD and AMD-impacted environments.

Bacteria↗
PubMed2001

Are metal mining effluent regulations adequate: identification of a novel bleached fish syndrome in association with iron-ore mining effluents in Labrador, Newfoundland.

Water quality guidelines for industrial effluents are in place in many countries but they have generally evolved within a limited ecotoxicological framework. Effluents from iron-ore mines have traditionally been viewed by regulatory bodies as posing little or no risk to the aquatic environment. However, it was recently reported that lake trout taken from a large iron-ore contaminated Lake in Labrador (Wabush Lake) had elevated levels of DNA oxidative damage and were markedly depleted in levels of vitamin A (Payne et al., 1998) in comparison with fish from a Lake (Shabogamo Lake) receiving lesser levels of effluents. Through further observations, it has now been established that the lake trout in Wabush Lake are commonly affected with a marked skin bleaching syndrome in comparison with fish in Shabogamo Lake and a nearby Lake (Ashuanipi) which does not receive effluents. To the authors' knowledge such a syndrome which is characterized by marked reduction in skin pigmentation and overall increase in skin whitening has not been reported before in any fish population in association with contamination. Preliminary information for liver histopathological and blood cell differences have also been obtained in fish in Wabush Lake in comparison with Ashuanipi Lake. It has also been observed through studies on phosphatidyl liposomes that iron-ore leachate contains redox-active material (iron but possibly other transition metals) that has considerable potential for causing oxidative damage to cellular constituents. Using the weight of evidence approach it is indicated that iron-ore effluents may pose more of a risk to the aquatic environment than traditionally considered by regulatory agencies.

Fish Diseases↗
PubMed1995

[An occupational physiology study at the Asarel Mining and Milling Works. The evaluation of the work load in the basic jobs in an open-pit mine].

This occupational physiology study was undertaken within a wider applied-research framework designed to evaluate the occupational environment and its impact on workers at "Asarel" Mining and Milling Works. Analysis of activities showed physical effort (dynamic and static) to be the major problem at the open pit, though varying in extent between jobs (most prominent for blasters and bulldozerists). Nervous/emotional strain, while not leading, was sustained mostly by diggers and blasters, followed by drivers. Organization of work (shift regimen, no regulated breaks, stepwise schedule of days off work) was hardly appropriate and did not allow for recovery. Interviewed workers qualified working conditions as extremely unfavorable; they disapproved with the physical factors of the occupational environment, the workplace, the state of machines and devices, and remuneration for work performed. Exertion from work, assessed by pulse rate and energy expended, was moderate for most activities of diggers, drivers, and drillers. The burden of physical effort was great for blasters at the open pit and for diggers and drillers performing extra repair operations (pulse rate, 100-110 strokes/min; energy expended, 5.2-5.5 Kcal/min). Hardest and least attractive was the work of blasters at stores for explosive materials (pulse rate, 120-141 strokes/min; energy expended, 5.5-6.5 Kcal/min). These adverse factors of labor activities might produce a negative impact on worker health and performance, leading to occupational impairment of their musculoskeletal system, to labor-related disorders of their cardiovascular and nervous systems, etc. Preventive measures are thus necessary to limit physical exertion, optimize the work-and-rest regimen; also, there is a need for conducting pertinent preventive medical examinations, providing social measures (conditions for transportation, rest, nutrition, sports), etc.

Adult↗
PubMed2001

Mining the chemical quarry with joint chemical probes: an application of latent semantic structure indexing (LaSSI) and TOPOSIM (Dice) to chemical database mining.

In this study we use a novel similarity search technique called latent semantic structure indexing (LaSSI) with joint chemical probes as queries to mine the MDL drug data report database. LaSSI is based on latent semantic indexing developed for searching textual databases. We use atom pair and topological torsion descriptors in our calculations. The results obtained with LaSSI are compared with another in-house similarity search technique TOPOSIM. The results from the similarity searches using joint chemical probes are significantly better than searches using single chemical probes for both LaSSI and TOPOSIM. The selected molecules are closely related in activity to their queries and are ranked among the top 300 scoring molecules of the 82 860 entries in the database. Our implementation of LaSSI is very fast and efficient in finding active compounds. The results also show that LaSSI consistently retrieves more diverse chemical structures representative of the joint chemical probes in comparison to TOPOSIM. The use of multimolecule topological probes to identify compounds complements the use of searching databases with 3D pharmacophore hypotheses.

Angiotensin-Converting Enzyme Inhibitors↗