Occupational Health and Safety Hazards Assessment of Underground Coal Mines and Brick Kilns Workers

Abstract

In the subcontinent, underground coal mining and brick making is carried out manually, requiring many of the labor force for traditional means of coal excavation and brick formation. During each stage of the task in the two industries, the workers' musculoskeletal system is under pressure. It gives rise to the ergonomic hazards. Moreover, the underground coal mines naturally have a high concentration of dust and a hot environment, which poses a significant threat to workers' respiratory tract, kidneys, and musculoskeletal system. To check the prevalence of musculoskeletal disorders, I selected 20 underground coal mines from four districts (Chakwal, Mianwali, Jehlum, and Khushab) and 15 brick kilns from two districts (Sialkot and Gujranwala) in the Punjab province for survey using Standard Nordic Musculoskeletal Questionnaire, Rapid Upper limb Assessment sheet, and Rapid Entire Body assessment sheet. A total of 260 workers (13 from each underground coal mine) were selected randomly. Regression models were created for pain in the upper and lower limbs and back of workers, whose mean age is 19.8 years (±SD 1.47). Results showed that the coal cutting as the most harmful work with odd ratios (ORs) 13.06 (95% CI 13.7-21.5) for lower back pain and 11.2 (95% CI 3.5-19.4) for upper back pain in participants performing six studied work tasks. Workers with more experience had higher odds of upper back pain (2.4, 95% CI 1.4-3.5) and lower back pain (3.3, 95% CI 1.1-4.4). The number of repetitions (mean value 25.85/minute with ±SD 9.48) are also significant for spinal disorders with ORs of 4.3 (95% CI 3.2-7.4) for the lower back and 1.3 (95% CI 1.0-2.4) for the upper back. The results also showed significance (with p< 0.05) of the 5 work stages for upper and lower limb disorder. The multiple bar chart showed the coal cutting as a hazardous stage because 96 coal cutters got upper limb disorder and 82 got lower limb disorder. The task of timbering and supporting was dangerous for the lower limb as reported by 25 workers, while relatively ii less risky for upper limbs as reported by 19 workers. Marked on RULA, all underground coal mining activities got the highest score (7/7), posing a threat to 100% workers' posture. Maximum workers (n=182) were in the age group of 26 years to 35 years, out of which 131 reported pain in lower limbs and 128 in upper limbs, and both have p <0.05. Frequency graphs showed age in the direct proportion of pain severity while the inverse proportion with a certain number of repetitions performed per minute. The socioeconomic profile of workers of the underground coal mines revealed that majority (n=221) workers earn 501$ to 550$ per month but have 0 education facility for their kids. Despite sufferings, only 5% of the workers were willing to mechanize the process of underground coal mines. Like the underground coal mines, the brick kilns‘ musculoskeletal disorders were also evaluated. For this, 105 male workers, and 45 female workers from 15 brick kilns were selected. About 96% of workers were involved in mixing and molding, 90% of males and 83% of females. The staff performing the spreading task reported pain/tiredness at the end of the day. The Chi-square test (using SPSS, 20 software) proved that the number and prevalence of workers (%) reported pain (in 9 body parts) varied with respect to the work stage they work at. 100% prevalence of pain in shoulders was present in three work stages. Digging and carrying tasks caused significant pain in the neck, upper back, shoulders, lower back, and hips. Mixing and molding tasks were most dangerous for most of the body parts and exhibited 7 scores on RULA. They also demonstrated high to very high-risk level as the REBA score was 9 and 13, respectively. The socioeconomic profile of the brick kiln workers identified residency of 83% of workers in the muddy house, low monthly income (<90.3 $) of 78% of workers, the higher tendency of alcoholism/smoking (48%-49%), lack of health facilities and higher illiteracy rate were also prevalent.iii For quantitative assessment of dust and other industrial hygiene parameters at underground coal mines, SKC Airchek 52 (SKC Inc., Eighty-Four, PA, USA) air sampling pumps, an anemometer, hygrometer, multi-gas detector, a thermometer, and modified International Union Against Tuberculosis and Lung Disease (IUATLD) respiratory questionnaire were used to collect data from 64 workers in 5 different mines of district Chakwal, Punjab, Pakistan. Among the mines studied for dust exposure, Mine E, with the lowest ventilation volumetric flow rate (18m3/s), have the highest dust concentration (4.27 mg/m3, silica content 1.83%). Conversely, mine A with the most increased ventilation volumetric flow rate (45m3 /s), has the lowest dust concentration (1.80 mg/m3, 0.93 % silica content). Survey results show 71% of workers inherited this occupation, 94% did not smoke, 99% did not use any dust mask, 47% have been diagnosed with tuberculosis, and 8% with asthma. About 57, 48, 44, and 42 workers reported cough, phlegm, chest tightness, and shortness of breath, respectively. Their physicians told 89% of the workers that dust exposure was a reason behind their respiratory ailments. To assess workers' heat exposure and the consequent impact on their kidneys, I selected 10 underground coal mines in district Chakwal. A total of 50 workers- divided into two sets, heat-exposed group (n=25) from 5 hot mines and non-heat- exposed group (n=25) from 5 relatively (observed during the walk-through survey) cool mines were sampled. An ingestible thermometric pill (Vital- senseTM, Respironics, Bend, Oregon) and skin temperature probes (model MLT422/A) were used to measure core body and skin temperature, respectively. Kestel 5400 (Nielson-Kellerman, Co., PA, USA), equipped with specific sensors, was used to measure relative humidity, globe temperature, and dry bulb temperature of mines. US-NIOSH health hazard evaluation of heat stress sheet and general questionnaire were used to collect data reporting on heat-related illnesses.iv Results showed the highest measured temperature and humidity were 33.6 0C in mine 1 and 83.3% in mine 3, respectively. All parameters of hydration and functioning of kidneys were evaluated in pre-and post-shift samples of urine and blood. The heat exposed group showed a decline in estimated glomerular filtration rate from pre- to post sampling (from100±19 to 94±09 mL/min; p<0.01). The serum uric acid was <7mg/dl. Creatinine (>30mg/g), urinary specific gravity (1.020) reduced, though remained within the prescribed range in all samples. All in all, the workers of the brick kilns and the underground coal mines are being exposed to occupational hazards, which necessitates an improvement in workers' working environment and ultimately in their quality of life. Well organized duty timings, modified working posture, job rotation, and preliminary training (in aspects of ergonomic intervention) perhaps manage these miseries. The output of both of the industries may increase many folds.