Examination of space/volume requirements for US underground coal mine refuge alternatives
ABSTRACT The Mine Safety and Health Administration requires that 1.4 m2 (15 ft2) of floor space is to be provided for each person inside a refuge alternative (RA). However, the amount of floor space needed for a person to reside inside an RA and perform basic tasks is unknown. During testing, participants entered into an RA or a simulated RA of various space/volume configurations and performed several simulated tasks that are representative of the survivability tasks performed within an RA. The results indicate that the floor space requirements were generally adequate for the tasks studied. Certain tasks such as changing scrubber cartridges, using toilets, and moving about the RA were impacted by the minimum height tested (0.6 m). As such, RAs of this height will require critical design consideration as a whole and the supplies provided for use inside of the RA to ensure the ability to use an RA.
Appropriate ingress/egress dimensions for mobile underground mining equipment
Sixteen male and sixteen female subjects were tested to determine appropriate ingress and egress opening dimensions for mobile underground mining equipment. Opening dimensions were determined for seating configurations used in five different seam heights: 81, 95, 123, 135, and 160 cm. A modified psychophysical methodology was used whereby each subject entered and exited a mock-up of a cab and adjusted the width of a sliding door to the minimum width that allowed for safe and comfortable ingress and egress. Each subject was given two trials for each seam height, for a total of ten trials per subject. Finally, the mean and 95th percentile opening widths were determined for each seam height. The mean opening widths, from lowest to highest seam height, are 132, 122, 112, 98, and 78 cm. The 95th percentile opening widths, from lowest to highest seam height, are 162, 149, 140, 122, and 101 cm. These values can be used by design engineers to provide adequate ingress and egress opening for mobile underground mining equipment.
Physiological responses to weight lifting in different planes.
A weight of 10 kg was lifted by 11 normal male volunteers (mean age 34·2 years) from ground to knee, hip, and shoulder levels in the sagittal, lateral and oblique planes. During these lifting manoeuvres intra-abdominal pressure was measured by telemetry and the activity of erector spinae and external oblique were recorded by electromyography. The values obtained for peak and sustained intra-abdominal pressure and the averaged electromyographic activities of erectores spinae and external obliques were subjected to analysis of variance and correlation analysis. A significant difference between the responses in these three planes was found: the sagittal plane activities evoke least response. Intra-abdominal pressures, erector spinae activity and external oblique activity were highly significantly correlated in each of the three planes.