Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Mining”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 667 records · Page 37Linked to original sources
PubMed2003

Monitoring of short-lived radon progeny in mines.

Obligatory measurements of the potential alpha energy concentration of short-lived radon progeny have been performing in the Polish underground mines since 1989. In consideration of economic aspects, an attempt was made from the very beginning to combine it with measurements of the dust concentration. Therefore the developed measuring units were an integral part of the dust samplers complying with the requirements of the State Mining Authority to apply them in underground mines. This way the developed devices could fulfil two measurement tasks simultaneously: measurement of the dust concentration and potential alpha energy concentration of short-lived radon progeny. The new device based on the thermoluminescence detectors is able to cooperate with the dust samplers made by the SKC company and equipped with a cyclone making it possible to operate them constantly for one working day. The lower limit of detection was equal about 0.04 microJ m(-3) at a 95% confidence level and 1 h pumping.

Air Pollutants, Occupational↗
PubMed2004

Radon exposure in uranium mining industry vs. exposure in tourist caves.

There is a fairly general consensus among health physicists and radiation professionals that exposure to radon progeny is the largest and most variable contribution to the population's exposure to natural sources of radiation. However, this exposure is the subject of continuing debate concerning the validity of risk assessment and recommendations on how to act in radon-prone areas. The purpose of this contribution is to situate the radon issue in Spain in two very different settings. The first is a uranium mining industry located in Saelices el Chico (Salamanca), which is under strict control of the Spanish Nuclear Safety Council (CSN). We have measured radon concentrations in different workplaces in this mine over a five-year period. The second setting comprises four tourist caves, three of which are located in the province of Cantabria and the fourth on the Canary Island of Lanzarote. These caves are not subject to any administrative control of radiation exposure. Measured air 222Rn concentrations were used to estimate annual effective doses due to radon inhalation in the two settings, and dose values were found to be from 2 to 10 times lower in the uranium mine than in the tourist caves. These results were analysed in the context of the new European Basic Safety Standards Directive (EU-BSS, 1996).

Air Pollutants↗
PubMed2006

Population dose in the vicinity of closed Hungarian uranium mine.

In order to determine the exposure to natural sources of radiation for people in the vicinity of remediated Hungarian uranium mine regional surveys were carried out. The surveys evaluated indoor radon concentrations and outdoor and indoor external gamma dose rates. Radon concentration has been measured with nuclear etched track detectors for 4 months in 129 houses in Kovágószolos and in 23 houses in Cserkút. In some houses measurements have been carried out for a year and the measurement results of the 4 months were corrected according to these. The corrected radon concentrations altered between 15 and 2314 Bq m(-3). An average of 257 Bq m(-3) in Kovágószolos and 125 Bq m(-3) in Cserkút was measured. The average was 434 Bq m(-3) for the 48 houses within 100 m of the passage of the former mine that is under the village of Kovágószolos. The higher values of Kovágószolos are likely to be the result of the influence of mining. The terrestrial gamma-ray dose rate was measured outdoors and indoors at these houses. Values of 139 (62-233) nGy h(-1) and 133 (93-275) nGy h(-1) were measured in Kovágószolos and Cserkút, respectively. The average annual effective doses for the two villages studied were 3 and 5 mSv y(-1), but the maximum value was 40 mSv y(-1).

Air Pollution, Indoor↗
PubMed2005

Radon concentration measurements in the Amasra coal mine, Turkey.

In this study, the results of atmospheric radon measurements that were performed for the Amasra underground coal mine in Zonguldak bituminous coal basin (Turkey) are presented. The radon measurements were performed for 40 days between November 2004 and December 2004 using passive nuclear etched track detectors. The radon concentrations vary from a minimum value 49 Bq m(-3) in a site located at +40 m to a maximum value 223 Bq m(-3) in a site located at -100 m. Mean concentration is 117 (Bq m(-3)). This value is well below the action level of 500-1,500 Bq m(-3) recommended by the International Commission on Radiological Protection (ICRP) (1993). The mean effective dose value for workers of this mine of 3.4 microSv per day was obtained. This result shows that protection against radiological hazards would not be necessary for workers of this mine((2)).

Air Pollutants, Occupational↗
PubMed1982

Radon daughter equilibrium and unattached fraction in mine atmospheres.

Measurements of the equilibrium between radon and its daughters in mine atmospheres are presented. The situation in mines seems to be too complex to be described by any simple theoretical model. There is however a good correlation between the equilibrium factor, F, and the individual daughter ratios. This suggests that the individual daughter concentrations may be assessed by Kusnetz-measurements of the equilibrium factor, F. Measurements by the wire screen method indicate that the dust concentration is the main influencing factor upon the unattached fraction of the radon daughters. The unattached fraction of the potential alpha-energy was lower than 0.05 in most mining situations. In areas with very clean air, the unattached fraction may however be higher than 0.3. Measurements indicated a good correlation between the unattached fraction of the potential alpha-energy and the unattached fraction of the individual daughter products. This suggests that assessments of the unattached fraction of the individual daughters may be obtained by using the Kusnetz method for measurements on the screen and back up filter.

Air Pollution, Radioactive↗
PubMed1982

Dose conversion factors for radon daughters in underground and open-cut mine atmospheres.

As uranium will be mined in Australia by open-cut methods, previous work on calculating dose conversion factors for radon daughters has been re-examined. The fractions of radon daughters deposited on lung airways and the factors for converting from equilibrium activity of radon daughters on airways to dose to basal cells are re-calculated. The variation around these estimates through variability of lung morphology and the depth of the basal cells is discussed. Average dose conversion factors calculated for atmospheres which may be typical of underground mines range from 12 mGy/WLM to 33 mGy/WLM. Use has been made of measurement results on unattached fraction at an open-cut mine in the Northern Territory, Australia, to derive dose conversion factors, ranging from 50 mGy/WLM to 135 mGy/WLM which are applicable to this environment.

Air Pollutants↗
PubMed1982

A study of radiation parameters in an open-pit mine.

Radiation parameters associated with the open pit mining of a small (10,000 tonnes), but high grade (2%) uranium deposit at Nabarlek, N.T., have been investigated in detail. External radiation levels, radon emanation rates and radon daughter levels were measured systematically during the development of the mine, and are correlated with ore grade, properties of the host rock and atmospheric conditions. Significant radon daughter concentrations were observed only under stable atmospheric conditions, usually during the might and were invariably associated with thermal inversions. The mean cumulative exposure to radon daughters was estimated from the measured levels to be 0.065 Working Level Months for employees working in the pit for the entire four and a half months of mining. The mean cumulative external gamma ray exposure for the same employee group was measured using thermoluminescent dosimeters to be 2.3 mSv (230 mrem). For most other employees, however, exposures were much lower. Data on long lived radionuclides in dust and on particle size distribution are also presented.

Air Pollution, Radioactive↗
PubMed1988

Relationship of 220Rn and 222Rn progeny levels in Canadian underground U mines.

Radon-222 and 220Rn progeny are found in some Canadian underground U mines. Because both can contribute to lung dose, their experimental determinations are important. The relationship between 222Rn progeny Working Level [WL(Rn)] and 220Rn progeny Working Level [WL(Tn)] has been investigated in U mines. Experimental measurements extended from 1981 to 1986 and consisted of about 700 measurements of each WL(Rn) and WL(Tn). The data were analyzed by standard linear and power-function regression analysis. A power-function relationship between WL(Rn) and WL(Tn) seemed to fit the experimental data best. The relationship obtained permits the calculation of WL(Tn) from experimental values of WL(Rn). The relationship is useful for lung-dose-calculation purposes and in mine-ventilation-engineering calculations.

Air Pollutants↗
PubMed1989

Health implications of radionuclide levels in cattle raised near U mining and milling facilities in Ambrosia Lake, New Mexico.

This study was conducted to determine radionuclide tissue levels in cattle raised near U mining and milling facilities. Ambrosia Lake, New Mexico, has been the site of extensive U mining for 30 y and contains several underground U mines, a processing mill, and two large U tailings piles. Ten cows were purchased from two grazing areas in Ambrosia Lake and ten control animals were purchased from Crownpoint, New Mexico. Muscle, liver, kidney, and bone tissue taken from these animals, and environmental samples, including water, grasses and soil collected from the animals' grazing areas, were analyzed for 238U, 234U, 230Th, 226Ra, 210Pb, and 210Po. Mean radionuclide levels in cattle tissue and environmental samples from Ambrosia Lake were higher in almost every comparison than those found in respective controls. Liver and kidney tissues were particularly elevated in 226Ra and 210Po. Radiation dose commitments from eating cattle tissue with these radionuclide concentrations were calculated. We concluded that the health risk to the public from eating exposed cattle is minimal, unless large amounts of this tissue, especially liver and kidney, are ingested.

Animals↗
PubMed1992

Navajo birth outcomes in the Shiprock uranium mining area.

The role of environmental radiation in the etiology of birth defects, stillbirths, and other adverse outcomes of pregnancy was evaluated for 13,329 Navajos born at the Public Health Service/Indian Health Service Hospital in the Shiprock, NM, uranium mining area (1964-1981). More than 320 kinds of defective congenital conditions were abstracted from hospital records. Using a nested case-control design, families of 266 pairs of index and control births were interviewed. The only statistically significant association between uranium operations and unfavorable birth outcome was identified with the mother living near tailings or mine dumps. Among the fathers who worked in the mines, those of the index cases had histories of more years of work exposure but not necessarily greater gonadal dosage of radiation. Also, birth defects increased significantly when either parent worked in the Shiprock electronics assembly plant. Overall, the associations between adverse pregnancy outcome and exposure to radiation were weak and must be interpreted with caution with respect to implying a biogenetic basis.

Abnormalities, Radiation-Induced↗
PubMed2003

Assessment of health risks to skin and lung of elevated radon levels in abandoned mines.

Radon, together with its progeny, is present in high levels in some underground sites. Radon is known to increase the risk of lung cancer, while increased levels of radon decay products on the skin surface have been implicated in skin cancer induction and at sufficient levels might cause deterministic effects such as erythema. Although radon levels in working mines are controlled, radon in abandoned mines can reach very high levels, which would result in an occupant exceeding recommended annual exposure limits in less than 2 h in some mines. The relative importance of dose limits for the lung, skin cancer, and deterministic effects is discussed in the light of practical experience.

Air Pollutants, Radioactive↗
PubMed2005

Cancer mortality during the 1968-1994 period in a mining area in France.

We performed a geographical analysis of cancer mortality in the communes surrounding an industrial mining complex (Salsigne, France) where suspicious levels of pollution due to arsenic were measured. Compared with that observed in a control area, we showed a significant excess of mortality due to all cancer types (ratio of standard mortality ratios (ratio of SMRs)=1.1), lung cancer (ratio of SMRs=1.8), pharynx cancer (ratio of SMRs=2.1) in the whole population, and due to digestive system cancer (ratio of SMRs=1.3) among women. The results were similar after controlling for the occupation distribution in the populations. Excluding mining complex workers deaths from the deaths in the studied populations did not modify the pattern of our results. We concluded that the excess of cancer deaths could not be exclusively due to potential professional exposures among the workers of the mining complex and are probably explained by environmental contamination.

Adult↗
PubMed2004

Metabolically active eukaryotic communities in extremely acidic mine drainage.

Acid mine drainage (AMD) microbial communities contain microbial eukaryotes (both fungi and protists) that confer a biofilm structure and impact the abundance of bacteria and archaea and the community composition via grazing and other mechanisms. Since prokaryotes impact iron oxidation rates and thus regulate AMD generation rates, it is important to analyze the fungal and protistan populations. We utilized 18S rRNA and beta-tubulin gene phylogenies and fluorescent rRNA-specific probes to characterize the eukaryotic diversity and distribution in extremely acidic (pHs 0.8 to 1.38), warm (30 to 50 degrees C), metal-rich (up to 269 mM Fe(2+), 16.8 mM Zn, 8.5 mM As, and 4.1 mM Cu) AMD solutions from the Richmond Mine at Iron Mountain, Calif. A Rhodophyta (red algae) lineage and organisms from the Vahlkampfiidae family were identified. The fungal 18S rRNA and tubulin gene sequences formed two distinct phylogenetic groups associated with the classes Dothideomycetes and Eurotiomycetes. Three fungal isolates that were closely related to the Dothideomycetes clones were obtained. We suggest the name "Acidomyces richmondensis" for these isolates. Since these ascomycete fungi were morphologically indistinguishable, rRNA-specific oligonucleotide probes were designed to target the Dothideomycetes and Eurotiomycetes via fluorescent in situ hybridization (FISH). FISH analyses indicated that Eurotiomycetes are generally more abundant than Dothideomycetes in all of the seven locations studied within the Richmond Mine system. This is the first study to combine the culture-independent detection of fungi with in situ detection and a demonstration of activity in an acidic environment. The results expand our understanding of the subsurface AMD microbial community structure.

Ascomycota↗
PubMed2006

Diversity of microorganisms in Fe-As-rich acid mine drainage waters of Carnoulès, France.

The acid waters (pH 2.7 to 3.4) originating from the Carnoulès mine tailings contain high concentrations of dissolved arsenic (80 to 350 mg.liter(-1)), iron (750 to 2,700 mg.liter(-1)), and sulfate (2,000 to 7,500 mg.liter(-1)). During the first 30 m of downflow in Reigous creek issuing from the mine tailings, 20 to 60% of the dissolved arsenic is removed by coprecipitation with Fe(III). The microbial communities along the creek have been characterized using terminal-restriction fragment length polymorphism (T-RFLP) and 16S rRNA gene library analyses. The results indicate a low bacterial diversity in comparison with unpolluted water. Eighty percent of the sequences obtained are related to sequences from uncultured, newly described organisms or recently associated with acid mine drainage. As expected owing to the water chemistry, the sequences recovered are mainly related to bacteria involved in the geochemical Fe and S cycles. Among them, sequences related to uncultured TrefC4 affiliated with Gallionella ferruginea, a neutrophilic Fe-oxidizing bacterium, are dominant. The description of the bacterial community structure and its dynamics lead to a better understanding of the natural remediation processes occurring at this site.

Arsenic↗
PubMed2007

Exposure to mercury in the mine of Almaden.

OBJECTIVES: To describe the process for obtaining mercury and the historical exposure of Almadén miners to mercury. METHODS: Information on every workplace and historical data on production, technological changes in the productive process and biological and environmental values of mercury was collected. A job-exposure matrix was built with these values and the exposure to inorganic mercury was estimated quantitatively as mug/l of urine mercury. A cumulative exposure index was calculated for every worker by adding the estimates for every year in the different workplaces. RESULTS: In the mine, the highest exposures occurred during drilling, with values up to 2.26 mg/m3 in air, 2194 microg/l in urine and 374 microg/l in blood. Furnace operation and cleaning were the tasks with the highest values in metallurgy, peaking up to 3.37 mg/m3. The filling of bottles with mercury by free fall gave values within a range of 1.13-2.43 mg/m3 in air; these values dropped to 0.32-0.83 mg/m3 after introducing a new ventilation system. The toxicity effects of high doses of inorganic mercury on the central nervous and urinary systems have been known for decades. CONCLUSIONS: The exposure of the workers in Almadén mines to mercury has been very high. The extremely high content cinnabar ore of the mine explains the increased concentrations of mercury in air at the work places. This, together with inadequate working conditions, explains the high mercury levels found in blood and urine during the study period.

Air Pollutants, Occupational↗
PubMed1980

Dust exposure and mortality in chrysotile mining, 1910-75.

We report a further follow-up of a birth cohort of 11 379 workers exposed to chrysotile. The cohort consisted of 10 939 men and 440 women, born 1891-1920, who had worked for at least a month in the mines and mills of Asbestos and Thetford Mines in Quebec. For all subjects, length of service and estimates of accumulated dust exposure were obtained, with a smoking history for the vast majority. Three methods of analysis, two based on the "man-years" methods, the other a "case-and-multiple-controls" approach, gave results consistent with one another and with previous analyses. By the end of 1975, 4463 men and 84 women had died. Among men, the overall excess mortality, 1926-75 was 2% at Asbestos and 10% at Thetford Mines, much the dustier region. The women, mostly employed at Asbestos, had a standardised mortality ratio (SMR) all causes, 1936-75) of 0.90. Analysis of deaths 20 years or more after first employment showed that in men with short service (less than five years) there was no discernible correlation with dust exposure. Among men employed at least 20 years, there were clear excesses in those exposed to the heaviest dust concentrations. Reanalysis in terms of exposure to age 45 showed definite and consistent trends for SMRs for total mortality, for lung cancer, and for pneumoconiosis to be higher the heavier the exposure. The response to increasing dose was effectively linear for lung cancer and for pneumoconiosis. Lung cancer deaths occurred in non-smokers, and showed a greater increase of incidence with increasing exposure than did lung cancer in smokers, but there was insufficient evidence to distinguish between multiplicative and additive risk models. There were no excess deaths from laryngeal cancer, but a clear association with smoking. Ten men and one woman died from pleural mesothelioma. If the only subjects studied had been the 1904 men with at least 20 years' employment in the lower dust concentrations, averaging 6.6 million particles per cubic foot (or about 20 fibres/cc), excess mortality would not have been considered statistically significant, except for pneumoconiosis. The inability of such a large epidemiological survey to detect increased risk at what, today, are considered unacceptable dust concentrations, and the consequent importance of exposure-response models are therefore emphasised.

Accidents↗
PubMed1985

Gastric cancer in coal miners: a case-control study in a coal mining area.

In collaboration with three pathology departments a case-control study was conducted in the southern part of the Netherlands to investigate the risk of gastric cancer in coal miners. Between 1 January 1973 and 31 December 1983, 323 male patients were diagnosed as having a malignant neoplasm of the stomach. For each case a control was selected from the same pathology department, matched on year of birth and regardless of diagnosis. The archives of the Central Coal Miners Pension Fund were searched to obtain information about whether or not a patient had ever worked for a coal mining company in the Netherlands. Twenty two per cent of the patients had been registered as an underground coal miner, compared with 20% of the control group (odds ratio of 1.14, 95% confidence interval: 0.33-1.73). Those with gastric cancer who had ever worked underground in a coal mine did so for an average period of 16.9 years compared with an average of 19.7 years in the control group. The study gives no indication that the underground workers of the Dutch coal mines had a raised risk of developing a malignant neoplasm of the stomach.

Adult↗
PubMed1982

Lead mine waste: hazards to livestock.

Waste from disused lead mines is used for a variety of purposes and has been implicated in outbreaks of lead poisoning in animals. Three outbreaks of lead poisoning, two in cattle and one in farm dogs, occurred in the south of Scotland. In the first outbreak, three housed suckler cows died and two were clinically affected but recovered after treatment. In the second, four heifers died and two recovered after therapy. Blood samples taken from cattle in both outbreaks contained lead in concentrations from 0 . 59 to 2 . 00 ppm (normal blood lead level 0 . 05 to 0 . 25 ppm). Post mortem examinations revealed signs of lead poisoning. Metallic particles in the rumens and abomasums of affected animals suggested mine waste as the source of the lead and subsequently it was found that the material had been used in the construction of a ramp over which silage was pushed (outbreak 1) and to fill potholes on the farm (outbreak 2). Covering the relevant areas with concrete prevented further occurrences. Farm dogs were affected over a period where mine waste was used to resurface a road. Two dogs died, six others showed signs of lead poisoning and others, with no clinical signs, had elevated blood lead levels.

Animals↗