Analysis of fatalities and injuries involving mining equipment 英语论文.doc

analysis of fatalities and injuries involving mining equipment athe pennsylvania state university, department of energy and mineral engineering, 110 hosler building, university park, pa 16802-5000, usabnuclear generating stationg2, hydro-quebec, department of industrial engineering, university of quebec, trois-rivieres, canadareceived 11 september 2006; revised 11 january 2007; accepted 15 march 2007. available online 23 july 2007. abstractintroductiondespite significant reductions, the number of injuries and fatalities in mining remains high. a persistent area of concern continues to be equipment-related incidents.尽管大幅减少，伤害和死亡人数在采矿仍然很高。阿持续关注的领域仍然是与设备有关的事件。methodmine safety and health administration (msha) and current population survey (cps) data were used to examine equipment-related injuries over the period 19952004. incidents were reviewed to determine which types of mining equipment were most often involved and to identify and characterize trends.resultsnon-powered hand tools was the equipment category most often involved with non-fatal injuries while off-road ore haulage was the most common source of fatalities.summaryyounger employees had an elevated risk of injury while workers 55years had an elevated risk for fatality. a large majority of incidents involve workers with 55年已为死亡风险升高。大部分的事故涉及与5年工作经验的工人。impact on industryresults should increase hazard awareness and enable mine management to select and prioritize problem areas and safety system weaknesses in both underground and surface mining.keywords: mining safety; equipment-related injuries; mining fatalitiesarticle outline1. introduction 2. methods 3. results and discussion 4. summary references vitae1. introductionthe mining industry is a vital economic sector for many countries including the united states and comprises the utilization of coal, metal, and non-metal minerals. the use of minerals by nations worldwide is extensive and includes electrical generation, production of cement, steel, agricultural lime, commercial and residential building products, asphalt, and medicines, as well as countless household, electronic, and other manufactured products. according to the mine safety and health administration (msha, 2006), there were 1,643 surface and underground coal mines, 199 metal mines, and 11,840 aggregate (stone, gravel, sand, etc.) mines in the united states in 2005. almost 345,000 employees are engaged in mining operations in the areas of production, preparation, processing, development, maintenance, repair, and shop or yard work. historically, mining has been one of the most hazardous work environments in many countries around the world. in addition, due to their severity and frequency, mining injuries, illnesses, and fatalities are among the costliest, for example, leigh, waehrer, miller, and keenan (2004) report that u.s. lignite and bituminous coal mining rank second in the nation for the average cost per worker for fatal and all nonfatal injuries and illnesses. the data for coal mines indicate a total of 311,965 injuries for the 28-year period from 1978 through 2005 (11,141 per year), and 183,940 injuries in the metal and non-metal sector (6,569 per year). the total number of fatalities for the same period was 1,835 in coal mining (65 per year) and 1,626 for metal and non-metal mining (58 per year). the historical record of injuries continues to show a significant decline and the number of fatalities has dropped from 267 in 1979 to 55 in 2004, the lowest number of mining fatalities ever recorded (msha, 2006).despite the record of progress that has been achieved in reducing mining injuries and fatalities, both the number and severity of mining accidents occurring are still unacceptable (kecojevic, komljenovic, groves, & radomsky, in press). three recent mining accidents, the 2002 mine inundation at quecreek, pennsylvania, and the 2006 explosion at sago mine and fire at alma mine no. 1, both in west virginia, have captured national attention, and highlighted the importance and urgency to further improve mine safety using the most effective approaches possible. continued improvement of miners safety and health requires a two-pronged approach to accident prevention, one that is fundamental and traditional (i.e., engineering, enforcement, and education) and one that is more innovative and creative (e.g., applying behavioral principles and technological advances to better control and eliminate hazards). the two approaches are synergistic the efficacy coming when both are applied simultaneously. planning as well as program and policy implementation must be followed by regular monitoring and control activities. future mine health and safety progress requires the systematic planning of appropriate safety programs and measures. the safety management decisions that must be made to select and prioritize problem areas and safety system weaknesses must be based on the recognition of hazards encountered in each activity of the mining process.according to msha records, the highest number of mine fatalities is attributed to the general category of equipment. this study was undertaken in order to more thoroughly characterize equipment-related mining injuries and to perform a descriptive analysis of those that occurred over the last 10-year period. injury statistics for surface and underground mining were combined for these analyses this decision was based on the preliminary nature of the analysis and on the desire to perform a more general program- or policy-level evaluation process that would facilitate the identification of priority areas for development of interventions and control strategies. subsequent implementation of specific control strategies would then take into account the type of mining operation and equipment that is unique to that operation. an analysis of both the temporal characteristics of the number of injuries for the period of 19952004, and descriptive statistics related to accidents and injuries is presented. in addition, the relationship between number of fatal accidents and the number of years of mining experience of the workers involved is examined.2. methodsmining accident, injury, and illness statistics were obtained from data collected by the mine safety and health administration (msha) under part 50 of the u.s. code of federal regulations via msha form 7000. electronic versions of these data files are maintained by the national institute for occupational safety and health (niosh). niosh has converted the electronic msha data files to spss and dbase iv file formats and has added additional computed fields. documentation for the database is available including the spss data dictionary, which describes all the fields and codes used to enter information. there are 61 fields including variables such as the msha mine id assigned to an operation, the month, day, year, and time of an incident, the mine machine involved, accident/injury/illness classification, accident type, age of employee, experience, injury type, total days lost, and job title.data files for 19952004 were downloaded from the niosh site and combined into a master database in microsoft access. the resulting file consists of 190,940 records for the 10-year time period with each record representing an accident, injury, or illness. all types of mining and both mine operators and contractors were included. database filters were developed to determine, for example, how many fatalities occurred each year, and with which mine machines the incidents were associated. results were further analyzed using minitab 13. the age distribution for the mining population was obtained from current population survey (cps) data. the cps is a monthly survey of approximately 60,000 households conducted by the bureau of labor and statistics (bls). the survey includes information on each employed member of the household including age, sex, industry, and occupation. age data for this study were extracted from monthly cps results.investigators often examine relationships between age, experience, and injuries. however, it is difficult to separate these effects since older workers typically have more experience. in a previous study of coal mining injuries (butani, 1988), a detailed demographics survey was conducted to collect information on characteristics such as principal equipment operated, experience at present job, and age for the general mining population. these results were then used as denominator data to determine whether age and experience, for example, were significant factors for injury. unfortunately, this type of demographic data are not available for the time period examined in this study the cps data provide only the age distribution and therefore cannot be used to separate age and experience effects. butani (1988) described a relative risk or “injury index” to compare and contrast various groups or subpopulations resulting from stratification by age and experience. the index is simply the ratio of percentage of injuries for the subpopulation to the percentage of total workers accounted for by the subpopulation. an injury index of 1.0 corresponds to an average risk while a value greater than 1.0 indicates a higher risk for that group.in order to compare the relative cost or severity of injuries associated with different types of mining equipment, the total number of lost workdays (hull, leigh, driscoll, & mandryk, 1996) was tabulated for each mine machine for the 10-year period. lost work days is a field in the msha data files (daystotl) and the msha part 50 diskette users handbook provides detailed schedules of charges to be applied to the different types of injury and impairment. under this system a fatality, any permanent total disability, and loss of sight (both eyes) each lead to 6,000days charged. charges for other injuries can range from 35days for the loss of the distal phalange of a toe, to 4,500days for the loss of an arm above the elbow. the total number of days charged to each type of mine machine from 19952004 was calculated by first filtering the database to include only those incidents associated with a mine machine, and then including those records for which the injury type was fatal (injtyp=1), or non-fatal days lost (injtyp=2). this yielded a table containing 56,450 records for injtyp=1 or 2 and 55,853 records for injtyp=2. the nfdl and total number of days lost was then accumulated and plotted by mine machine code.3. results and discussiona total of 190,940 accidents, injuries, and illnesses were recorded from 19952004. of these, 160,627 (84%) were attributed to fatalities, non-fatal days lost injuries (nfdl), or no days lost (ndl) injuries. the remaining 30,313 incidents included events and illnesses such as roof falls (53%), repeated trauma injuries (16%), hoisting accidents (7%), and dust disease (6%). there were 775 fatalities reported, of which 597 (77%) were associated with a piece of mining equipment / machinery. nfdl and ndl injuries accounted for 159,852 incidents with 86,398 (54%) of these associated with mining machinery. when fatalities, nfdl, and ndl injuries are combined, 54% of the 160,627 incidents were associated with machinery. finally, 93,207 (49%) of the 190,940 recorded incidents showed the involvement of mining equipment.a plot of annual injuries and fatalities shows a downward trend over the 10year period (fig. 1). fatalities decreased in number from 97 in 1995 to 55 in 2004, while nfdl and ndl injuries decreased from 13,852 and 6,869 in 1995, to 8,183 and 3,867 in 2004, respectively. these changes represent decreases of 43%, 41%, and 44% for fatalities, nfdl, and ndl injuries, respectively, from 19952004. msha statistics show that during this same time frame, the fatal injury rate decreased from 0.0303 to 0.0184, while the injury rate decreased from 6.30 to 4.05. coal production during this period was relatively constant ranging from 1,030 to 1,128 million tons, while the number of small mines (all types of mining, five or fewer employees) increased from 5,923 to 6,918. although a continued decrease in the number of fatalities is apparent, the rate of fatal injury per 100,000 workers in mining (16.7) was still more than four times higher than the average rate for all industries (4.1) in 2004 (us department of labor, bureau of labor statistics, current population survey, census of fatal occupational injuries).full-size image (19k)fig. 1.non fatal days lost injuries (nfdl), no days lost (ndl) injuries, and fatalities per year.view within articlea histogram of accident, illness, and injury classifications for the 190,940 incidents (fig. 2a) shows a large portion (54%) related to material handling, followed by slip or fall of person (16%), machinery (12%), hand tools (11%), roof fall (10%), and powered haulage (8%). exposure to chemical and physical agents accounts for approximately 4% of the incidents collectively, including 4,805 disorders associated with repeated trauma, and 1,731 involving dust diseases of the lung. the large fraction of incidents related to material handling, machinery, hand tools, and powered haulage is consistent with previous surveillance reports and reflects the general nature of mining operations (niosh, 2000). a similar histogram prepared for fatalities (fig. 2b) shows that powered haulage (33%) and machinery (18%) classifications account for 51% of the fatal incidents. this represents an increase in the fraction of fatalities for these categories compared to the 19861995 surveillance report (niosh, 2000) in which powered haulage and machinery were associated with 44% of the fatalities, and suggests that larger proportional reductions in fatalities may have been achieved in other areas such as the electrical and ground fall categories.full-size image (82k)fig. 2.frequency of accident / illness / injury classifications for a) all incidents (n=190,940), and b) fatalities (n=775).view within articlefig. 3 shows the frequency of involvement of the different types of mining machinery for fatalities only (injtyp=1), and for nfdl and ndl injuries combined (injtyp=2 or 3). the plot for fatalities shows that off highway and underground ore haulage trucks (code 44) account for the largest portion of the fatalities (95, 16%) followed by front-end loaders (54, 9%), continuous miners (12, 8%), conveyors (38, 6%), (non-ore haulage) trucks (38, 6%), and cranes/derricks (32, 5%). the remaining types of equipment each accounted for less than 5% of the fatalities. referring to the nfdl and ndl injuries plot, non-powered hand tools are involved in 20,435 incidents (24%), which is more than three times greater than the next most frequently recorded machinery category, rock or roof bolting machines (7,078, 8%). off highway ore haulage trucks (5,633, 6%), front end loaders (5,376, 6%), and conveyors (4,280, 5%) are again among the top five most frequently involved types of equipment.full-size image (139k)fig. 3.distribution of fatalities (injtyp=1), and nfdl (injtyp=2) and ndl (injtyp=3) injuries by mine machine involved (minemach).view within articlea detailed study of the risks of hand tool injury in underground coal and metal-nonmetal mining found that most injuries are associated with scaling bars, jacks, and pneumatic drills. the non-powered hand tools used in mining are generally larger and heavier than household versions of the same tools and are often used under difficult conditions. the larger weight and size of the tools increases the risk of injuries due to dropping, slipping, or overexertion while using the tools. further, conditions in mines often require the use of tools in awkward positions, which increases the risk of injury. the prevalence of recordable injuries associated with non-powered hand-tool use indicates that significant challenges still remain in controlling these risks.the estimated days lost for fatalities and nfdl injuries combined (total days lost), and for nfdl injuries alone (non-fatal days lost) are distributed by the mine machines involved in fig. 4. incidents associated with off highway ore haulage account for the largest quantity of total days lost (766,874, 12%) followed by front end loaders (494,644, 8%), conveyors (440,300, 7%), non-powered hand tools (428,515, 7%), and continuous miners (388,089, 6%). however these results are largely influenced by the use of a 6,000day charge for fatalities, which complicates interpretation. when nfdl injuries are considered alone the five types of equipment with the largest number of days charged were non-powered hand tools (326,515, 12%), rock or roof bolting machines (229,117, 9%), conveyors (212,300, 8%), off highway ore haulage (196,874, 8%), and front end loaders (170,644, 6%). if the average number of days lost per nfdl injury is used as a measure of severity, results indicate that machine code 63 (slusher, scraper hoist, scram, scram level) produced the most severe injuries with an average of 155days lost per incident (n=11), while the least severe injuries were observed for machine code 11 (classifier, cyclones) with an average of 14days charged per injury (n=12). only machines having greater than 10 incidents over the 10year period were included for this comparison. if the analysis is restricted further to machines involved in more than 100 nfdl injuries, the most severe injuries were seen for surface mine-, ore-, or coal-cars (code 42) with 113days lost per incident (n=336), while the least severe injuries were recorded for welding machine (code 70) injuries with an average of 24days lost per incident (n=1,636).full-size image (61k)fig. 4.estimated days lost by mine machin