The human factors of mineworker fatigue: An overview on prevalence, mitigation, and what's next.

BACKGROUND: Though mining remains a vital shiftwork industry for U.S. commerce, problems of continued prevalence of mineworker fatigue and its mitigation persist. Publications and reports on fatigue in mining appear to be rich and diverse, yet variable and remote, much like the industry itself. METHODS: The authors engaged in a brief nonexhaustive overview of the literature on sleep and fatigue among mineworking populations. RESULTS: This overview covers: potential sources of fatigue unique to mine work (e.g., monotonous and disengaging Work Tasks, underground environments and light exposure, remote work operations); evaluation of mitigation strategies for mineworker fatigue or working hours (e.g., shift-scheduling and training); and areas for future research and practice (e.g., fatigue risk management systems in mining, mineworker sleep and fatigue surveillance, lighting interventions, and automation). CONCLUSIONS: Fatigue continues to be a critical challenge for the mining industry. While research on the problems and solutions of mineworker fatigue has been limited to date, the future of fatigue research in mining can expand these findings by exploring the origins, nature, and outcomes of fatigue using advancements in lighting, automation, and fatigue risk management.

Evaluating preferences for colorectal cancer screening in individuals under age 50 using the Analytic Hierarchy Process.

BACKGROUND: In 2021, the United States Preventive Services Task Force updated their recommendation, stating that individuals ages 45-49 should initiate screening for colorectal cancer. Since several screening strategies are recommended, making a shared decision involves including an individual's preferences. Few studies have included individuals under age 50. In this study, we use a multicriteria decision analysis technique called the Analytic Hierarchy Process to explore preferences for screening strategies and evaluate whether preferences vary by age. METHODS: Participants evaluated a hierarchy with 3 decision alternatives (colonoscopy, fecal immunochemical test, and computed tomography colonography), 3 criteria (test effectiveness, the screening plan, and features of the test) and 7 sub-criteria. We used the linear fit method to calculate consistency ratios and the eigenvector method for group preferences. We conducted sensitivity analysis to assess whether results are robust to change and tested differences in preferences by participant variables using chi-square and analysis of variance. RESULTS: Of the 579 individuals surveyed, 556 (96%) provided complete responses to the AHP portion of the survey. Of these, 247 participants gave responses consistent enough (CR < 0.18) to be included in the final analysis. Participants that were either white or have lower health literacy were more likely to be excluded due to inconsistency. Colonoscopy was the preferred strategy in those < 50 and fecal immunochemical test was preferred by those over age 50 (p = 0.002). These results were consistent when we restricted analysis to individuals ages 45-55 (p = 0.011). Participants rated test effectiveness as the most important criteria for making their decision (weight = 0.555). Sensitivity analysis showed our results were robust to shifts in criteria and sub-criteria weights. CONCLUSIONS: We reveal potential differences in preferences for screening strategies by age that could influence the adoption of screening programs to include individuals under age 50. Researchers and practitioners should consider at-home interventions using the Analytic Hierarchy Process to assist with the formulation of preferences that are key to shared decision-making. The costs associated with different preferences for screening strategies should be explored further if limited resources must be allocated to screen individuals ages 45-49.

LED Area Lighting to Reduce Glare for Roof Bolter Operators.

Researchers from the National Institute for Occupational Safety and Health (NIOSH) developed a light-emitting diode (LED) area luminaire called the Saturn and conducted a laboratory study using a Fletcher High Dual-boom Mast Feed (HDDR) roof bolting machine. The Saturn luminaire was designed to (1) enhance floor illumination to enable better detection of trip hazards in the interior spaces of a roof bolter and (2) reduce glare that has typically been an issue of concern on roof bolters. This paper reports on the results of achieving the second objective. The existing roof bolter lighting was the baseline and was compared with three versions of the Saturn luminaire relative to light intensity (100%, 75%, and 50%). Discomfort and disability glare data were obtained from 30 participants that comprised three age groups. Discomfort glare perceptions were obtained using the De Boer rating scale, and disability glare was quantified by using Mars Letter Contrast Sensitivity tests. Discomfort glare was reduced at least 3 levels with all Saturn versions. Also, a predictive model was used to estimate discomfort glare, and the results were similar. Disability glare was the least for the Saturn's 50% intensity, and all Saturn versions had significantly less disability glare than with the baseline lighting. Veiling luminance was calculated and used as another indicator of disability glare. Veiling luminance was 28 to 42 times greater with the baseline lighting as compared with that of the Saturn lighting. Lastly, visibility levels were calculated. The Saturn versions were 4 to 6.5 times better in terms of visibility level.

Effects of Light Spectrum on Luminance Measurements in Underground Coal Mines.

Lighting regulations for luminance in U. S. coal mines are verified in the field by using a luminance photometer calibrated to the Standard Illuminant A light source. Significant measurement errors can exist when measuring light sources that are dissimilar to light sources used to calibrate the photometer. This paper quantifies the measurement errors when measuring these dissimilar light sources commonly used in U.S. underground coal mines-an LED, a CFL with a clear cover, a CFL with an amber cover, and a tungsten halogen. The impact of photometer quality was also evaluated. Three different luminance measuring instruments of high, medium, and low quality were compared-a PR-650, LS-100, and PMEX, respectively. The PMEX was under evaluation for measuring luminance compliance in U.S. underground coal mines. The PR-650 was used as the referent to which the other photometers were compared. The PMEX error ranged from -17.0% to -26.5% with the highest error for the amber CFL. The LS-100 closely matched the luminance measurement for the LED and halogen; however, it had a percent error of -10.4% for the amber CFL. After the initial experiment, MSHA made improvements to the PMEX resulting in the PMEX-MSHA. The experiment was replicated using the new photometer and the newer PR-670. After repeating the experiment, the measurement errors ranged from -16% to -19% for the PMEX-MSHA, thus indicating an improvement over the PMEX. These results show that the spectral content of a light source and the photometer quality can greatly impact the accuracy of luminance measurement.

The effect of cap lamp lighting on postural control and stability.

Researchers at the National Institute for Occupational Safety and Health (NIOSH) are conducting mine illumination research with the objective of improving miner safety. Slips, trips, and falls (STFs) are the second leading accident class (18.1%, n = 2,374) of nonfatal lost-time injuries at underground mines (MSHA, 2005-2009). Factors contributing to STFs include recognition of hazards as well as postural balance and age. Improved lighting may enable better hazard recognition and reduce the impact of postural balance and age. Previous research has shown that cap lamp technology that used light-emitting diodes (LEDs) has improved hazard detection. This study was an initial investigation to determine if cap lamp lighting significantly influences measures of static postural stability (displacement and velocity of center of pressure). Results of this investigation showed no significant differences in the balance measures of interest between cap lamps tested. However, balance was shown to significantly decline (p < 0.05) when tested in an underground coal mine compared to the laboratory testing condition. Relevance to industry: Underground coal mine workers wear cap lamps on their hard hats as their primary light source to illuminate nearby areas where their vision is directed. Proper illumination may improve miner safety by improving their STF hazard recognition and balance.

Visual performance for trip hazard detection when using incandescent and led miner cap lamps.

INTRODUCTION: Accident data for 2003-2007 indicate that slip, trip, and falls (STFs) are the second leading accident class (17.8%, n=2,441) of lost-time injuries in underground mining. Proper lighting plays a critical role in enabling miners to detect STF hazards in this environment. Often, the only lighting available to the miner is from a cap lamp worn on the miner's helmet. The focus of this research was to determine if the spectral content of light from light-emitting diode (LED) cap lamps enabled visual performance improvements for the detection of tripping hazards as compared to incandescent cap lamps that are traditionally used in underground mining. A secondary objective was to determine the effects of aging on visual performance. METHOD: The visual performance of 30 subjects was quantified by measuring each subject's speed and accuracy in detecting objects positioned on the floor both in the near field, at 1.83 meters, and far field, at 3.66 meters. Near field objects were positioned at 0 degrees and +/-20 degrees off axis, while far field objects were positioned at 0 degrees and +/-10 degrees off axis. Three age groups were designated: group A consisted of subjects 18 to 25 years old, group B consisted of subjects 40 to 50 years old, and group C consisted of subjects 51 years and older. RESULTS: Results of the visual performance comparison for a commercially available LED, a prototype LED, and an incandescent cap lamp indicate that the location of objects on the floor, the type of cap lamp used, and subject age all had significant influences on the time required to identify potential trip hazards. The LED-based cap lamps enabled detection times that were an average of 0.96 seconds faster compared to the incandescent cap lamp. Use of the LED cap lamps resulted in average detection times that were about 13.6% faster than those recorded for the incandescent cap lamp. The visual performance differences between the commercially available LED and prototype LED cap lamp were not statistically significant. IMPACT ON INDUSTRY: It can be inferred from this data that the spectral content from LED-based cap lamps could enable significant visual performance improvements for miners in the detection of trip hazards.