Ergonomic risk assessment of lifting operations by mud mixing operators at oil rigs.

Oil rigs require mud as a drilling fluid to make boreholes into the earth for crude oil exploration. The operator movements in drilling rigs are repeated bending, lifting of sacks for mud mixing, pushing and/or pulling of sacks and working in hazardous body postures. This study adopts risk assessment tools such as rapid entire body assessment and the revised National Institute for Occupational Safety and Health lifting equation to analyse the risks in postures of the mud mixing operator. Also, the study develops a digital human model of the mud mixing operator using Jack digital human modelling for simulating selected tasks associated with mud mixing operation. Finally, lower back analysis and static strength prediction are performed using a digital human Jack model. Safety of mud mixing operators can be improved with the results obtained from the study, thereby reducing non-productive time reports in drilling operations.