Evaluation And Intervention On Occupational Health Hazards In A Joint Venture Mining Company

Mining is an ancient occupation and a multi-disciplinary industry. The In-depth Reviews in this issue are intended to cover the topics that remain most important in mining today. The main occupational health hazards miners exposed include noise, heat and humidity, crystalline silica dust, metals (as arsenic, lead, manganese and mercury, etc.), diesel particulates, cyanide, hazardous or toxic gases underground (as methane, carbon dioxide and hydrogen sulphide gas, etc.), etc. This gold mining site located in Guizhou province of China. Crude ore contains sulphur, arsenic and mercury. Pilot production started in 2007 and underground mining started in 2009, while work-related abnormalities started to exist at that time (2009).ObjectiveTo understand the work process and productive technology for golden mining, occupational health hazards for miner and their exposure level, to conduct effective occupational health protection and promotion intervention measures or program, it’s necessary to investigate occupational exposure and life environments, health status for gold miners and existing occupational health management system in this mining company. This study will focus on health hazards risk assessment and effects of intervention programs for this gold mining, providing scientific information and data for occupational health program for mining in China.MethodMulti-designed epidemiological methods were combined in this work:1) Qualitative method:participation observation on workplace and life environments, control measures, work styles and unhealthy behaviors; Individual interviews were conducted for EHS staff, management and target employees to understand on-site occupational health management system; Collection and look throμgh of occupational health and management documentation and records to know current status of occupational health work and programs.2) Collection and analysis of workplace monitoring data from third party, establishment of internal workplace hazards monitoring plan for local EHS useing direct-reading sampling tools to monitor workplace dust, mercury and noise level.3) Quantitative Method:Collection and analysis of 2008-2011 occupational health examination data by descriptive research, layed analytic method and Logistic regression method.4) Intervention study:programs such as occupational health training and consultation, control measure improvements, internal monitoring plan establishmen and evaluation of the effectiveness by self-reported questionnaire in terms of occupational health knowledge, awareness, attitudes and behaviors changes.Results1. Technical Characteristics of Gold Mine and Occupational Health Management Status1) With author involvement in 2009, site took the OH advices and invited third party to conduct hazards evaluation which help them update occupational health documentations such as work process, risk evaluation, workplace monitoring data and list of equipments and facilities.2) According to update work process and hazards evaluation in 2009, underground mining’s risk were dust, arsenic, noise and hazardous gas underground; while process plant include grinding & floation, BIOX, CCD, CIL and golden room, due to which, author reclassify work position.3) According to occupational health management activities audit, rate of implementation on target OH activites is only 25%(4/16). After involvement and corrective action by author, rate increased to 87.5%.4) In 2009, rate of filing key occupational health records was only 25% while it became 87.5% with support of author later.5) in 2009, no regular plan on hazards evaluation while it was completed and involved in regular OH activities. However, incompletes control measures observed on site.6) Good job on employee health management and emergency response.2. Workplace Hazards Internal Monitoring ResultsFrom the end of 2010, EHS began to conduct internal monitoring on noise, dust and mercury once every month in 2 workplaces. Results showed that 1) suspected mistakes on respiratory dust results for trolley and forklift were found in 3rd party report, whose C-TWA is 0.36 and 0.56,μg/m3 which is not in the range of monitoring results. This need to be further clarified with vendor.2) Internal monitoring results were higher than those from third party. Mercury results of golden room were 47.37μg/m3 whose maximum value was 666.84μg/m3, while results from third party was<3μg/m3; Results of dust and noise were higher than those from third party.3) All the sampling points of dust from truck, trolley, forklift, etc. in underground mining were exceeding national OELs (0.7mg/m3), and the peak level was 11.3mg/m3. Underground mining is high risk for dust overexposure.4) High risk area for mercury vapor is golden room (4.58-666.84μg/m3) and carbon recovering room (0.62-844.2).5) Most area of underground mining, air blower, ball-milling, golden room, Lime preparation and crusher from process plant were high risk areas for noise exposure, whose noise level were from 85-110.3dB.3. Occupational Health Examination Results of Miners1)From 2008-2011, number of workers with elevated mercury and arsenic level were decreased, from 3.55%(11/310) and 5.48%(17/310) down to 1.05%(5/477) and 0%(0/477), respectively. (χ2=16.73 and 6.75, p<0.01) Number of workers with abnormal chest x ray and lung function were from 14.19%(44/310) and 9.35% (29/310) down to 2.94% 14/477) and 0% respectively (χ2=44.57å'Œ126.69, p<0.01). 2) Laying by age, number of workers with abnormal chest x ray from age group from 41-60y were much higher than other group (12.8%,17/133, x2=21.59, p<0.01); Meanwhile, number of those from working or exposing for 16-25y group were much higher than other groups in their classification (13.00% and 12.79%,χ2=21.116, p=0.002 andχ2=18.421, p=0.005).3) The logistic regression analysis,showed process plant (workplace) were protective factor for hearing loss, (χ2=4.13, p=0.04); working for 6-15 years groups is more risk than those under 5 years to develop abnormal chest x ray (OR=9.18, p=0.01).4. Effectiveness Study for Intervention Program1) Occupational Health knowledge were improved after intervention, ratio of workers knowing occupational disease increased from 75.6% up to 97.7%(p<0.01); knowing type of occupational hazards increased from 43.2% up to 73.3%(p<0.01); knowing noise hazard increased from 45.3% up to 74.9%(p<0.01) and knowing transmission route of Hepatitis B increased from 44.8% up to 73.2%(p<0.01).2) Occupational health attitudes and behavior changes were observed:ratio of workers requiring health examination, wearing PPEs, dust mask for dust exposure, half-mask for mercury exposure and earplμg for noise exposure used to be 89.3%,79.8%,79.8%, 76.0% and 85.71%, and after intervention, increased up to 96% and even 100% (p<0.01).3) Ratio of workers with self-reported bad health status decreased from 9.1% to 4.1%; self-reported suspected work-related abnormal symptoms were from 74.9% to 63.2%(p<0.01); overweight and obesity decreased from 47.1% to 37.7%.4) Ratio of workers attending occupational health training at least once increased from 0% to 84.3%.Conclusion1) Main hazards on these sites include dust, noise, mercury and arsenic.2) With involvement and support of our research team, this company established occupational health documentation system and launched majority of occupational health activities.3) Golden room and carbon recovering room were high risk areas for mercury over-exposure. Underground was high risk area for dust and noise over-exposure. Crushing and ball-milling of process plant were high risk areas for dust overexposure. Internal monitoring results were all higher than those from third party, which reflects on-site real exposure environment.4) 2008-2011 occupational health examination results showed number of most abnormal findings decreased. Work for 5-16 years was risk factor for abnormal chest x ray. More observation and analysis need on future health data.5) After intervention, occupational health knowledge, attitudes and behavior change of workers were improved obviously. Number of self-reported bad health decreased. The effectiveness of intervention was positive.