Control of dust in underground coal mines is critical for mitigating both safety and health hazards.For decades,the National Institute of Occupational Safety and Health(NIOSH)has led research to evaluate the effective...Control of dust in underground coal mines is critical for mitigating both safety and health hazards.For decades,the National Institute of Occupational Safety and Health(NIOSH)has led research to evaluate the effectiveness of various dust control technologies in coal mines.Recent studies have included the evaluation of auxiliary scrubbers to reduce respirable dust downstream of active mining and the use of canopy air curtains(CACs)to reduce respirable dust in key operator positions.While detailed dust characterization was not a focus of such studies,this is a growing area of interest.Using preserved filter samples from three previous NIOSH studies,the current work aims to explore the effect of two different scrubbers(one wet and one dry)and a roof bolter CAC on respirable dust composition and particle size distribution.For this,the preserved filter samples were analyzed by thermogravimetric analysis and/or scanning electron microscopy with energy dispersive X-ray.Results indicate that dust composition was not appreciably affected by either scrubber or the CAC.However,the wet scrubber and CAC appeared to decrease the overall particle size distribution.Such an effect of the dry scrubber was not consistently observed,but this is probably related to the particular sampling location downstream of the scrubber which allowed for significant mixing of the scrubber exhaust and other return air.Aside from the insights gained with respect to the three specific dust control case studies revisited here,this work demonstrates the value of preserved dust samples for follow-up investigation more broadly.展开更多
A study of an environmental assessment of dust fall and the associated heavy metal contents was conducted during the period from the first of March 2011 to the end of February 2012 at adjoining area of a phosphate fer...A study of an environmental assessment of dust fall and the associated heavy metal contents was conducted during the period from the first of March 2011 to the end of February 2012 at adjoining area of a phosphate fertilizer plant. Around the industrial area 8 dust fall stations were established and one of them was built upwind far from pollution activities to be taken as a control sample. Dust fall samples collected monthly weighed and then prepared to be analyzed through Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) to obtain heavy metal concentration. Meteorological parameters influencing the distribution of dust fall such as wind speed and direction, temperature, humidity, rain fall and pressure were determined. Results showed that deposition flow rates were 38.2. 47.5, 57.7, 44.3, 39.4, 38.2, 42.7 and 5.9 g/m2·month for the sites No., 1, 2, 3, 4, 5, 6, 7 and 8 respectively, and were compared with the findings of other investigators of like industrial areas worldwide. Levels of heavy metal As, Cu, Pb, Zn, Cd, and Hg in the deposited dust fall were 3.30, 26.46, 22.33, 235.00, 4.53 and 3.80 μg/g respectively. Enrichment coefficients of the heavy metals in the dust fall were found to be significant and reached the values 1.81, 0.90, 0.85, 0.65, 0.41 and 0.35 for zinc, lead, cadmium, copper, mercury and arsenic respectively. The paper ends with results and recommendations suggesting a methodology to remediate the investigated area polluted with heavy metals and control measures for the fertilizer plant to reduce pollution into the surrounding environment.展开更多
基金CDC/NIOSH for funding this research(75D30119C05529)。
文摘Control of dust in underground coal mines is critical for mitigating both safety and health hazards.For decades,the National Institute of Occupational Safety and Health(NIOSH)has led research to evaluate the effectiveness of various dust control technologies in coal mines.Recent studies have included the evaluation of auxiliary scrubbers to reduce respirable dust downstream of active mining and the use of canopy air curtains(CACs)to reduce respirable dust in key operator positions.While detailed dust characterization was not a focus of such studies,this is a growing area of interest.Using preserved filter samples from three previous NIOSH studies,the current work aims to explore the effect of two different scrubbers(one wet and one dry)and a roof bolter CAC on respirable dust composition and particle size distribution.For this,the preserved filter samples were analyzed by thermogravimetric analysis and/or scanning electron microscopy with energy dispersive X-ray.Results indicate that dust composition was not appreciably affected by either scrubber or the CAC.However,the wet scrubber and CAC appeared to decrease the overall particle size distribution.Such an effect of the dry scrubber was not consistently observed,but this is probably related to the particular sampling location downstream of the scrubber which allowed for significant mixing of the scrubber exhaust and other return air.Aside from the insights gained with respect to the three specific dust control case studies revisited here,this work demonstrates the value of preserved dust samples for follow-up investigation more broadly.
文摘A study of an environmental assessment of dust fall and the associated heavy metal contents was conducted during the period from the first of March 2011 to the end of February 2012 at adjoining area of a phosphate fertilizer plant. Around the industrial area 8 dust fall stations were established and one of them was built upwind far from pollution activities to be taken as a control sample. Dust fall samples collected monthly weighed and then prepared to be analyzed through Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) to obtain heavy metal concentration. Meteorological parameters influencing the distribution of dust fall such as wind speed and direction, temperature, humidity, rain fall and pressure were determined. Results showed that deposition flow rates were 38.2. 47.5, 57.7, 44.3, 39.4, 38.2, 42.7 and 5.9 g/m2·month for the sites No., 1, 2, 3, 4, 5, 6, 7 and 8 respectively, and were compared with the findings of other investigators of like industrial areas worldwide. Levels of heavy metal As, Cu, Pb, Zn, Cd, and Hg in the deposited dust fall were 3.30, 26.46, 22.33, 235.00, 4.53 and 3.80 μg/g respectively. Enrichment coefficients of the heavy metals in the dust fall were found to be significant and reached the values 1.81, 0.90, 0.85, 0.65, 0.41 and 0.35 for zinc, lead, cadmium, copper, mercury and arsenic respectively. The paper ends with results and recommendations suggesting a methodology to remediate the investigated area polluted with heavy metals and control measures for the fertilizer plant to reduce pollution into the surrounding environment.
