Effect of a simulated mine rescue on physiological variables and heat strain of mine rescue workers

Workplace Safety North (2015) reported 945 injuries related to mining in 2014 in Ontario, requiring the deployment of 53 emergency response teams. These statistics demonstrate the high risks of serious injury and fatality in the mining industry. Frequently occurring accidents include: underground fires, falls-of-ground, mobile equipment collisions, exposure to harmful environments, and falls from heights, which often require rescue (Government of Ontario, 2015b; Handbook of Training in Mine Rescue and Recovery Operations, 2014, Workplace Safety North Injury Statistics, 2015; Stewart, McDonald, Hunt, & Parker, 2008). Therefore, Mine operators rely on mine rescue teams, who have specialized skills in these issues, to save lives during an underground emergency. Mine Rescuers regularly participate in training simulations, which require teams of five to seven members, to solve a hypothetical rescue problem while timed and observed by judges (Handbook of Training in Mine Rescue and Recovery Operations, 2014). Simulations typically involve trapped miners who have to be found and rescued under challenging circumstances (T. Hanley, personal communication, December 15, 2017). Mine rescuers carry heavy gear (approximately 100lbs), including a metal stretcher, spare breathing apparatus, hydraulic equipment, and first aid supplies; while wearing personal protective equipment (e.g. Selfcontained breathing apparatus (SCBA), gloves, helmet, coveralls, boots etc.) (Handbook of Training in Mine Rescue and Recovery Operations, 2014). Research studying mine rescue participants demonstrate metabolic workloads between 400-700 Watts, with short bouts exceeding 1000 Watts; and often have concurrent heart rates nearing 100% of estimated maximum heart rate (HRmax estimated) (Stewart et al., 2008; Tomaskova, Jirak, Lvoncik, Buzga, Zavadilova, & Trlicova, 2015). In addition to extreme physical demands, underground mine conditions are often characterized by temperatures exceeding 40 °C, as well