Mirza Muhammad Zaid, Nana Kobina Amoako Amoah, Guang Xu* 
Increased exposure of the respirable coal dust leads to irreversible lung diseases in mine workers. MSHA mandates a maximum dust concentration of 1.5 mg/m3 in underground coal operations. Current ways of monitoring concentrations using filter-based method or expensive PDM3700 monitors cannot provide real time concentration. Low-cost light scattering PM sensors have the potential to overcome these challenges. Experiments were performed based on factorial design to evaluate the impact of wind velocity and sensor direction on the sensor response. Three levels of wind velocity 3m/sec, 1.5 m/sec & 0.5 m/sec and sensor direction as towards the stream, perpendicular to the stream and opposite to the stream and were evaluated. The results showed that the direction of the sensor has significant impact on the sensor response. For each input concentration 0-1 mg/m3, 1-2 mg/m3 and 2-3 mg/m3, PSM 5003 sensor has the superior response than any other sensor used in this research. This study will provide valuable information on the feasibility of using these sensors to make real time decisions. 

In environments where excavation is used to break rock, airborne rock dusts pose respiratory health threats to workers. This includes mining with mechanical excavators which are common in industrial minerals as well as some tunneling operations. The purpose of this study is to compare characteristics of rock dusts generated by pick cutters at different wear conditions such that results could be used in the evaluation of proper bit management and dust suppression controls in the underground environment. The study included laboratory full scale cutting of concrete, limestone, and sandstone samples where each rock was cut with three conical picks at new, moderately worn, and fully worn stages of wear. Dust samples were analyzed to reveal the concentrations, mineralogy, particle shapes, and particle size distributions. The results show that for all rock types, the worn pick consistently generated the highest concentration of dust, all picks consistently generated dust containing quartz, and all three picks consistently generated dust particles of similar shapes. Additionally, although there are slight shifts in the particle size distributions between the various pick wears, all the particle sizes reside in the respirable range less than 10µm in aerodynamic diameter for all the rock types cut in this experiment.

Prolonged exposure to high concentrations of respirable coal mine dust causes coal workers' pneumoconiosis and silicosis. Roof bolter operators in underground coal mines have a higher risk of coal dust overexposure. The canopy air curtain (CAC) was developed by NIOSH to protect roof bolter operators from excessive coal dust exposure. The CAC dispenses streams of airflow over the breathing zone of the operator to provide an impenetrable air curtain which prevents coal dust from entering the breathing zone of the operator. However, current CAC generation has an efficiency of 46% due to non-uniform airflow distribution across the plenum indicating rooms to improve the design. This study therefore redesigns the CAC using a two-level manifold system with optimized flow distribution that effectively protects roof bolters from coal dust exposures. The Simplex Evolutionary Operation (EVOP) optimization algorithm and Computational fluid dynamics (CFD) simulations are used to optimize the uniformity of airflow distribution across the plenum to achieve the optimum uniformity. A physical model of the optimized design is built, and lab tested in an experiment to validate the results from the CFD simulations. The improved CAC design is capable of keeping roof bolter operators' dust exposure levels below permissible limits.

This paper details the development of an immersive simulation tool that can be used to provide enhanced 3D visualization of monitoring and computational modeling datasets of dust and ventilation flow in an interactive, virtual environment, and clearly demonstrate the exposure impact of certain working condition changes and dust mitigation practices in gateroad development panels. To achieve this aim, onsite dust monitoring with AM520i and PDM3700 dust monitors and computational fluid dynamics (CFD) modeling were conducted to gain an improved understanding of dust and airflow characteristics around the continuous miner (CM) and evaluate different practices for dust controls. An algorithm was then developed to process large amounts of datasets exported from CFD into a form that can be visualized in a virtual reality (VR) environment using standalone VR headsets. A VR-CFD-based training tool in the form of VR headsets has been developed and used as an educational platform to create an effective communication of WH&S awareness of dust exposure in the workplace for CM operators and provide industry workforce (CM operators and development crews) training that enhances knowledge learning and operational practices for dust exposure reduction.