Acceptable workloads for three common mining materials

Area of Science:

• Occupational Ergonomics
• Mining Safety
• Human Factors Engineering

Background:

• Underground coal mining involves physically demanding tasks, including manual lifting of supplies.
• Assessing the safety and feasibility of lifting tasks is crucial for preventing injuries.

Purpose of the Study:

• To establish maximum acceptable weights of lift (MAWL) for common underground coal mine supply items.
• To investigate the influence of lifting posture and conditions on MAWL and physiological costs.
• To provide evidence-based recommendations for safe lifting workloads in mining environments.

Main Methods:

• Conducted psychophysical lifting studies with 12 experienced underground coal miners.
• Evaluated lifting of rock dust bags, ventilation stopping blocks, and crib blocks.
• Investigated four postures (standing, stooping under 1.5m/1.2m ceilings, kneeling) and four lifting conditions (symmetry, height).
• Measured physiological costs (energy expenditure) during lifting tasks.

Main Results:

• Posture significantly affected MAWL for rock dust bags; stooped postures increased physiological costs.
• Lifting height significantly impacted energy expenditure, while lifting plane had minimal effect.
• Recommended MAWL: 20.0 kg for rock dust bags, 16.5 kg for ventilation stopping blocks, and 14.7 kg for crib blocks.

Conclusions:

• Miners frequently handle supplies exceeding psychophysically acceptable lifting limits.
• Current workloads may pose risks due to excessive lifting weights and strenuous postures.
• Ergonomic assessments and revised workload recommendations are needed to improve miner safety.