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PubMed2002

Radon dynamics and reduction in an underground mine in Brazil. Implications for workers' exposure.

This work was aimed at studying the behaviour of 222Rn in an experimental underground copper mine in Brazil with a single entrance. The 222Rn concentrations, meaured by using a dynamic radon measuring technique. varied between 30.5 Bq.m(-3), during ventilated conditions applied to the mine galleries, and 19.4 x 10(3) Bq.(-3) for non-ventilated conditions and when operational mining activities were conducted inside. High radon concentration surges were observed after blasting and drilling activities. In the cases of inadequate ventilation, it was estimated that workers could be subjected to exposures as high as 10 microSv.h(-1), only due to 222Rn and its short-lived progeny. The results show the importance of real-time measurements to evaluate radon dynamics during mining operations.

Air Pollutants, Radioactive↗
PubMed2005

Occupational radiation exposure to norms in a gold mine.

Preliminary studies have been conducted into the occupational radiation exposure to NORMS from surface and underground mining operations in a gold mine in the Ashanti Region of Ghana. A brief description of the methods and instrumentation is presented. The annual effective dose has been estimated to be 0.26 +/- 0.11 mSv for surface mining and 1.83 +/- 0.56 mSv for the underground mines using the ICRP dose calculation method. The results obtained are found to be within the allowable limit of 20 mSv per annum for occupational exposure control recommended by the ICRP.

Background Radiation↗
PubMed2003

Changing patterns of knowledge, reported behaviour and sexually transmitted infections in a South African gold mining community.

BACKGROUND: In 1998, a major HIV intervention project was started in a mining community in Carletonville, South Africa. This included community-based peer education, condom distribution, syndromic management of sexually transmitted infections (STI), and presumptive STI treatment for sex workers. OBJECTIVES: To investigate changes in sexual behaviour and the prevalence of STI before and 2 years after the start of the HIV prevention programme. METHODS: Cross-sectional surveys were carried out in 1998 and 2000 among mine workers, sex workers and adults in the community. Demographic and behavioural factors were recorded and participants were tested for syphilis, gonorrhoea and chlamydial infection and, at the start of the intervention, for HIV. RESULTS: In 1998, the prevalence of HIV among men and women in the general population, mine workers, and sex workers, was 20%, 37%, 29% and 69%, respectively. In 2000, syphilis, gonorrhoea and chlamydial infection had increased among mine workers; chlamydial infection had increased among men and women, and syphilis had increased among women. There was evidence of positive behaviour change but this was not substantial or universal. Knowledge of HIV/AIDS and awareness of the epidemic were high but condom use remained low. CONCLUSION: There was little evidence of significant behaviour change and the prevalence of curable STI increased. The prevention programme had had less impact than expected. Reasons for the reduced impact, and the lessons for future intervention projects are discussed. There is a need for further monitoring of the HIV epidemic especially as its impact increases.

Adult↗
PubMed1983

Indoor radon progeny exposure in the Florida phosphate mining region: a review.

This paper reviews the data generated in studies of land radioactivity and indoor airborne radon progeny associated with mined and reclaimed phosphate lands in Florida. Highest indoor radon progeny levels are associated with the slab-on-grade type of construction. Concentrations exceeding 0.03 WL are associated with overburden soils, deposits and fill, while concentrations up to about 0.03 WL are associated with tailings. The lower limit for distinguishing increases above non-enhanced natural concentrations is on the order of 0.01-0.02 WL. Results of this study show that about 25% of the land produced by present methods of mining and reclamation practices would require restrictions on the type of construction or would require special construction methods. It is projected that with modification of mining and tailings disposal practices, virtually all of the land produced by mining and reclamation would be satisfactory for unrestricted construction use.

Background Radiation↗
PubMed1986

Pre-operational survey of a U mine near Val Vedello, Italy.

Results obtained from radiometric research carried out from 1980-81 in the region of U mines in the Val Vedello are provided. Data are presented on 222Rn, 226Ra and natural U concentrations in spring and surface waters. Concentrations were found to be relatively low. There is some increase in the vicinity of the exploratory U mine but this is, at least up to the present, only of a local character. Data are presented on external gamma exposure, 210Pb and 210Po in foodstuffs and in the urine of normal and exposed population as well as 226Ra in milk and vegetable samples. The aim of this study is to outline a preliminary map of natural radioactivity on the site before starting the mining activity. This will enable us later to detect changes caused by the U mining, milling and mill-tailing disposal operations.

Air Pollutants, Radioactive↗
PubMed1988

Plutonium mining for cleanup.

Cleanup is the act of making a contaminated site relatively free of Pu so it may be used without radiological safety restrictions. Contaminated ground is the focus of major cleanups. Cleanup traditionally involves determining Pu content of soil, digging up soil in which radioactivity exceeds guidelines, and relocating excised soil to a waste-disposal site. Alternative technologies have been tested at Johnston Atoll (JA), where there is as much as 100,000 m3 of Pu-contaminated soil. A mining pilot plant operated for the first 6 mo of 1986 and made 98% of soil tested "clean", from more than 40 kBq kg-1 (1000 pCi g-1) to less than about 500 Bq kg-1 (15 pCi g-1) by concentrating Pu in 2% of the soil. The pilot plant is now installed at the U.S. Department of Energy Nevada Test Site for evaluating cleanup of other contaminated soils and refining cleanup effectiveness. A full-scale cleanup plant has been programmed for JA in 1988. In this paper, previous cleanups are reviewed, and the mining endeavor at JA is detailed. "True soil cleanup" is contrasted with the classical "soil relocation cleanup." The mining technology used for Pu cleanup has been in use for more than a century. Mining for cleanup, however, is unique. It is envisioned as being prominent for radiological and other cleanups in the future.

Decontamination↗
PubMed2000

Evidence of declining STD prevalence in a South African mining community following a core-group intervention.

OBJECTIVES: To reduce the prevalence of curable sexually transmitted diseases (STDs) in a South African mining community through provision of STD treatment services, including periodic presumptive treatment and prevention education to a core group of high-risk women living in areas around the mines. METHODS: Women at high risk for STDs attended a mobile clinic monthly for examination and counseling, and were treated presumptively for bacterial STDs with a directly observed 1-g dose of azithromycin. Gonococcal and chlamydial infection rates were measured by urine ligase chain reaction, and genital ulcers were assessed by clinical examination. Changes in STD prevalence among local miners were assessed through comparison of prevalence in two cross-sectional samples of miners taken 9 months apart, and through routine disease surveillance at mine health facilities. RESULTS: During the first 9 months of the intervention, 407 women used the services. Baseline prevalence of Neisseria gonorrhoeae and/or Chlamydia trachomatis in women was 24.9%; 9.7% of these women had clinical evidence of genital ulcer disease (GUD). The proportion of women with incident gonococcal or chlamydial infections at the first monthly return visit (69% follow-up rate) was 12.3%, and genital ulcers were found in 4.4% of these women. In the miner population, the prevalence of N gonorrhoeae and/or C trachomatis was 10.9% at baseline and 6.2% at the 9-month follow-up examination (P<0.001). The prevalence of GUD by clinical examination was 5.8% at baseline and 1.3% at follow-up examination (P< 0.001). Rates of symptomatic STDs seen at mine health facilities decreased among miners in the intervention area compared with miners living farther from the site and with less exposure to the project. DISCUSSION: Provision of STD treatment services to a core group of high-risk women may significantly reduce their burden of disease, and may contribute to a reduction in community STD prevalence. In the absence of sensitive and affordable screening tests for STDs in women, periodic presumptive treatment coupled with prevention education is a feasible approach to providing STD services in this population.

Adult↗
PubMed1981

Health concerns in uranium mining and milling.

Mortality of uranium miners from both lung cancer and other respiratory diseases is strongly dependent on exposure to radon daughters, cigarette smoking and height. Lung cancer among 15 different mining groups (uranium, iron, lead, zinc) was analyzed to determine what factors influence incidence and the induction-latent period. At low exposure or exposure rates, alpha radiation is more efficient in inducing lung cancer, producing an upward convex exposure-response curve. The induction-latent period is shortened by increased age at start of mining, by cigarette smoking and by high exposure rates. For a follow-up period of 20 to 25 years, the incidence increases with age at start of mining, with magnitude of exposure and with amount of cigarette smoking. Instead of extrapolating downward from high exposures to estimate risk at low levels, it is suggested that it might be more appropriate to use cancer rates associated with background radiation as the lowest point on the exposure-response curve. Although health risks are much greater in uranium mines than mills, there is some health risk in the mills from long-lived radioactive materials.

Age Factors↗
PubMed1988

Follow-up study of pulmonary function and respiratory tract symptoms in workers in a Swedish iron ore mine.

In 1967, 240 workers in the Kiruna, Sweden, mine were examined with regard to lung function and respiratory symptoms. Seventeen years later, 167 of these workers were reexamined using a structured interview which covered respiratory symptoms, smoking habits, and workplace, and lung function tests, including dynamic spirometry and closing volume. The prevalence of chronic bronchitis in the present study was 9.6%. There was a strong relationship between chronic bronchitis and smoking but no relationship between chronic bronchitis and working underground in the mine. Only three persons had chronic obstructive lung disease. In the still active mine workers, dynamic spirometry results showed no difference between smokers or nonsmokers or between underground and surface workers. Thus, we found no excess of chronic obstructive lung disease or lung function disturbances in the mine workers studied. This probably reflects a self-selection process whereby the workers with airway obstruction due to smoking or underground exposure have left underground work and also the company. Underground workers with chronic mucous hypersecretion, on the other hand, have not felt motivated, because of this, to leave underground work. Some, however, may have stopped smoking but not necessarily because of the hypersecretion.

Adult↗
PubMed1998

Effects of the intensity and timing of asbestos exposure on lung cancer risk at two mining areas in Quebec.

Mortality data from 9609 workers at two asbestos mining areas in Quebec were analyzed to assess the effects of the intensity and timing of exposure on lung cancer risk. Summary exposure measures based on differing assumption were computed for lung cancer cases and matched controls and were fitted to the data using conditional logistic regression. A non-linear relationship between intensity and risk fit both mining areas, but risk was greater at one area than the other. At the mine with lower risk, exposure occurring more than 30 years prior to death had little effect, while at the other mine risk did not vary with time since exposure and men starting employment before 1924 were at elevated risk. The results point to differences in dust composition at the two areas and illustrate the difficulties in estimating risk.

Adult↗
PubMedDate not supplied

A strategy for modeling ground water rebound in abandoned deep mine systems.

Discharges of polluted water from abandoned mines are a major cause of degradation of water resources worldwide. Pollution arises after abandoned workings flood up to surface level, by the process termed ground water rebound. As flow in large, open mine voids is often turbulent, standard techniques for modeling ground water flow (which assume laminar flow) are inappropriate for predicting ground water rebound. More physically realistic models are therefore desirable, yet these are often expensive to apply to all but the smallest of systems. An overall strategy for ground water rebound modeling is proposed, with models of decreasing complexity applied as the temporal and spatial scales of the systems under analysis increase. For relatively modest systems (area < 200 km2), a physically based modeling approach has been developed, in which 3-D pipe networks (representing major mine roadways, etc.) are routed through a variably saturated, 3-D porous medium (representing the country rock). For systems extending more than 100 to 3000 km2, a semidistributed model (GRAM) has been developed, which conceptualizes extensively interconnected volumes of workings as ponds, which are connected to other ponds only at discrete overflow points, such as major inter-mine roadways, through which flow can be efficiently modeled using the Prandtl-Nikuradse pipe-flow formulation. At the very largest scales, simple water-balance calculations are probably as useful as any other approach, and a variety of proprietary codes may be used for the purpose.

Algorithms↗
PubMedDate not supplied

Predictability of surface mine spoil hydrologic properties in the Appalachian Plateau.

Prevention of acid mine drainage at surface coal mines in the Appalachian region relies to an extent on minimizing ground water contact with acid-forming materials, and maximizing ground water contact with alkalinity-yielding materials. Acid-forming materials are often selectively handled to minimize or prevent contact with ground water. Controlling ground water contact with acidic or alkaline materials depends on forecasting the level and range of fluctuation of the postmining water table within the mine backfill. Physical measurements and aquifer testing of more than 120 wells from 18 reclaimed mines in Kentucky, Ohio, Pennsylvania, and West Virginia have led to improved forecasting of the postmining ground water system. Factors that influence the ground water regime include spoil lithology and particle size, age of reclamation, spoil thickness, distance from the final highwall, and pit floor dip angle and direction. Spoil hydraulic conductivity (K) exhibits a 95% confidence interval range of six orders of magnitude about a mean K of 1.7 x 10(-5) m/sec. Spoil aquifer saturated thickness is related to the overall thickness of the spoil, the lithology of the spoil, dip of the pit floor, and distance to the highwall. Saturated spoil thickness has a 95% confidence interval of 2.2 to 3.6 m about the mean of 2.9 m. The predicted saturated zone averages 19% of the total spoil thickness.

Appalachian Region↗
PubMed1997

Prevalence of occupational lung disease among Botswana men formerly employed in the South African mining industry.

OBJECTIVE: To determine whether previous health experiences affect the prevalence of occupational lung disease in a semirural Botswanan community where there is a long history of labour recruitment to South African mines. METHOD: A cross sectional prevalence study of 304 former miners examined according to a protocol including a questionnaire, chest radiograph, spirometry, and medical examination. RESULTS: Overall mean age was 56.7 (range 28-93) years, mean duration of service 15.5 (range 2-42) years. 26.6% had a history of tuberculosis. 23.3% had experienced a disabling occupational injury. Overall prevalence of pnemoconiosis (> 1/0 profusion, by the International Labour Organisation classification) was 26.6%-31.0%, and 6.8% had progressive massive fibrosis (PMF). Many were entitled to compensation under South African law. Both radiograph readers detected time response relations between pneumoconiosis and PMF among the 234 underground gold miners. PMF could result from < 5 years of exposure, but was not found < 15 years after first exposure. Both pulmonary tuberculosis (PTB) and pneumoconiosis were found to be associated with airflow limitation. CONCLUSIONS: Former miners in Botswana have a high prevalence of previously unrecognised pneumoconiosis, indicative of high previous exposures to fibrogenic respirable dust. Their pneumoconiosis went unrecognised because they had no access to surveillance after employment. Inadequate radiographic surveillance or failure to act on results when employed or when leaving employment at the mines could have contributed to under recognition. Community based studies of former miners are essential to fully evaluate the effects of mining exposures. Our findings indicate a failure of established measures to prevent or identify pneumoconiosis while these miners were in employment and show that few of the social costs of occupational lung diseases are borne by mining companies through the compensation system.

Accidents, Occupational↗
PubMed2003

The impact of roster changes on absenteeism and incident frequency in an Australian coal mine.

BACKGROUND: The occupational health and safety implications associated with compressed and extended work periods have not been fully explored in the mining sector. AIMS: To examine the impact on employee health and safety of changes to the roster system in an Australian coal mine. METHODS: Absenteeism and incident frequency rate data were collected over a 33 month period that covered three different roster schedules. Period 1 covered the original 8-hour/7-day roster. Period 2 covered a 12-month period under a 12-hour/7-day schedule, and period 3 covered a 12-month period during which a roster that scheduled shifts only on weekdays, with uncapped overtime on weekends and days off (12-hour/5-day) was in place. Data were collected and analysed from the maintenance, mining, and coal preparation plant (CPP) sectors. RESULTS: The only significant change in absenteeism rates was an increase in the maintenance sector in the third data collection period. Absenteeism rates in the mining and CPP sectors were not different between data collection periods. The increase in the maintenance sector may be owing to: (1) a greater requirement for maintenance employees to perform overtime as a result of the roster change compared to other employee groups; or (2) greater monotony associated with extended work periods for maintenance employees compared to others. After the first roster change, accident incident frequency decreased in the CPP sector but not in the other sectors. There was no effect on incident frequency after the second roster change in any sector. CONCLUSIONS: The current study did not find significant negative effects of a 12-hour pattern, when compared to an 8-hour system. However, when unregulated and excessive overtime was introduced as part of the 12-hour/5-day roster, absenteeism rates were increased in the maintenance sector. The combination of excessive work hours and lack of consultation with employees regarding the second change may have contributed to the overall negative effects.

Absenteeism↗
PubMed1984

Kaolin dust concentrations and pneumoconiosis at a kaolin mine.

Kaolin is removed from underground seams in the mining area to a processing area, where it is sliced, dried, and pulverised to make the finished product. A study was undertaken to determine the dust concentrations in various work areas and to assess the prevalence of radiographic and pulmonary function abnormalities in 65 workers at a Georgia kaolin mine. Respirable dust concentrations were higher in the processing area than in the mine or maintenance areas for all determinations from 1977 to 1981. The mean respirable dust level in the processing area in 1981 was 1.74 mg/m3 and 0.14 mg/m3 in the mine area. Five workers, all of whom had worked at the processing area, had radiographic evidence of kaolin pneumoconiosis. The mean values of forced vital capacity (FVC) and FEV1 of the entire group were within the normal range. When the spirometric values were expressed as a percentage of the predicted values, the FVC and FEV1 were significantly lower in the workers with kaolinosis than in other workers in the processing area. The FVC and FEV1 also declined significantly with increasing years of work in the processing area. The FEV1/FVC%, however, was not significantly altered either by the presence of kaolinosis or by an increasing number of years of work, indicating that the impairment was restrictive and hence likely to be a consequence of dust inhalation rather than smoking. In this study the highest dust concentrations occurred in the processing area, and kaolin pneumoconiosis was limited to those who had worked there. Kaolin exposure appeared to have a small but significant effect on ventilatory capacity in those with kaolin pneumoconiosis and in workers with a longer exposure. There was no association between the radiographic appearances of kaolinosis and cigarette smoking or between the presence of radiographic abnormalities and reduced arterial blood gas tensions.

Adult↗
PubMed1989

Hard-rock mining exposures affect smokers and nonsmokers differently. Results of a community prevalence study.

The physiologic consequences of occupational dust exposure, their relation to smoking, and their reversibility with cessation of exposure remain controversial. To address these questions, we studied a random sample of male residents of Leadville, Colorado when the major employer, a hard-rock mine, had been closed for 5 to 11 months. Subjects were interviewed for respiratory symptoms and occupational history, underwent plethysmographic measurements of lung volume and airflow, and performed a single breath diffusing capacity procedure. Dyspnea was the only respiratory symptom exacerbated by mining exposures. Cumulative dust exposure, estimated with historic respirable dust measurements for mining job titles and weighted by time at the job, was associated with decreases in maximal expiratory flow rates when controlled for smoking, age, and height. However, determinations of plethysmographic lung volume that allowed calculation of flow rates at equivalent absolute lung volume indicated that dust effects differed in never-smokers and smokers. In never-smokers, dust exposure was associated with decreased lung volume, increased flow rates, and increased DLCO/VA. In smokers, dust exposure was associated with increased lung volume, lower flow rates, and lower DLCO/VA than that accounted for by smoking. We suggest that hard-rock mining exposures result in irreversible pulmonary function changes of airflow limitation in smokers and of a restrictive nature in never-smokers.

Adult↗
PubMed1982

Respiratory abnormalities in employees of the hard rock mining industry.

Respiratory symptoms, forced vital capacity, and the single breath N2 test were assessed in male employees (25 to 54 yr of age) who had been employed for more than 5 yr in the mining industry in Manitoba. The results were compared with those in a similar group of men selected from the general population. The prevalence of cough and/or phlegm in both nonsmoking and smoking mining employees was significantly greater than that in the sample of the general population (p less than 0.05). In both nonsmokers and ex-smokers amongst the mining employees, the parameters derived from the single breath N2 test tended to be lower and maximal expiratory flow rates tended to be higher than in comparable groups in the general population sample. In smokers, FVC, FEV1, FEV1/FVC, maximal expiratory flow rates, RV/TLC, and the slope of phase III were significantly worse in smelter workers than in underground workers. Alterations in lung function in those who worked underground, but not in those who worked in the smelter, was related to the duration of employment in the industry. The data suggest that exposure to mining irritants may result in disorders of lung function, and that this effect is greater in cigarette smokers.

Adult↗
PubMed2005

Sustainable waste management in the Indian mining industry.

One of the important sectors that contribute to the national economy is the mining sector. During the mining of minerals and ores, waste materials in the form of overburden are generated. As these are not useful to the mine owners, they may be inappropriately disposed of into the environment, posing serious threat to the environment in the form of land degradation, water and air pollution. The present paper discusses the existing status of waste generation, its characteristics and the disposal methods being adopted in India. Impacts associated with waste disposal practices together with preventive measures for waste disposal are also discussed. Finally, strategies for improvements in existing waste management and for incorporating the same in the overall development plan for the mines are suggested.

Coal↗