Modelling the risk factors of occupational accidents in an underground coal mine in Turkey using regression analysis

CIM Bulletin, Vol. 1, No. 1091, 2006

M.K. Ozfirat, P.M. Ozfirat, C.O. Aksoy, C. Pamukcu and C. Tatar

The file is a zipped PDF document.Temporal and other factors contributing to the occurrence of occupational accidents at an underground coal mine in Turkey between the years 1992 to 2000 have been analyzed. Occupational accidents in mines result in both loss of time and money, and can cause debilitating injury or death and intense hardship imposed on family, friends, and dependents, for which no amount of compensation is sufficient. Thus, occupational accidents should be analyzed carefully in order to prevent future occurrences.The purpose of the study was to determine which, if any, of the factors studied contributed to the occurrence of accidents so that the mine could take the necessary steps to reduce the risk to the workforce. Regression analysis was used to determine the strength of the relationship between each factor studied and the number of occupational accidents.Accident reports written between 1992 and 2000 were collected and classified according to the cause of the accident. The number of accidents that occurred in each category was then recorded. There are many factors that contribute to the risk of an accident in an underground mine. The present study considered the following factors: mining system; type of shift; day of week; month of year; age of employee; total yearly production; total yearly labour; and total coal production in a year in tons of coal. The qualitative variables among these factors (mining system, type of shift, day of week, month of year, and age of employee) were quantified using relative scales, starting from one. Risk can be viewed as the probability of an accident’s occurrence, whereas the number of accidents in each category was divided by the number of workers working in the corresponding range. As a result of this operation, the rate of each accident was achieved (i.e. risk of each accident). These numbers were then graphed according to the factors contributing to the occurrence of accidents in order to decide whether to use a linear or polynomial regression model; polynomial regression was used with all the variables. The effects of the day of week, age, and month of year on the rate of accdents were considerably high; however, the effects of total yearly production, type of shift, and total yearly labour were very low. Total production and total labour were expected to be very influential on the rate of accidents. This was not reflected in the regression models because they do not include the effects of the mining system. Prior to 1997, hand-worked mining methods were used. Since then, both the mechanized mining methods and hand-worked mining methods are used in production. Therefore, the type of mining system was considered along with total production and total labour. Polynomial regression was used to determine the effects of these factors. As a result, total labour was found to be a factor on the rate of accidents, whereas total production did not have considerable influence.In conclusion, day of week, age of employee, total labour, and month of the year were found to be the most influential factors. Considering these factors, some recommendations were made for the mine schedule. If precautions are taken, it is believed that risk of the occurrence of occupational accidents in the mine would decrease substantially.