Improving the ventilation system at Rosh Pinah zinc mine

Abstract

capable of providing adequate quantity and quality of air to all working faces, and is critical to the occupational health, safety, and comfort of underground employees (Luxbacher and Ramani, 1977; Exikis and Kapageridis, 2006). No ventilation system can remain adequate indefinitely; as the mine workings are extended, the ventilation characteristics such as system pressures, air volumes, leakages, and airway resistances change considerably. Continuous improvement of the ventilation system is needed to ensure compliance with health and safety regulations (Lovejoy, 2010). It also ensures that the right quality and quantity of air is delivered to all the necessary areas at the lowest possible cost. This can be achieved by identifying inefficient airways and poorly ventilated areas in the mine and planning how best to upgrade them. The latest geological exploration shows that the focus of production at Rosh Pinah mine is shifting towards the western orefield (WOF). As mining progressed, the working areas have advanced away from the main fans, which increased the resistance to air flow drastically and resulted in increasing demands being imposed on the main fan in order to supply an adequate air flow. This process also created more leakage paths between the fan and the working areas, which has caused the air to short-circuit before it can reach the faces. Consequently, a much larger quantity of air has to be circulated by the fan so that the stipulated quantity reaches the face, which increases operating costs (Singh et al., 2004). An investigation was carried out to optimize the existing ventilation system along the WOF at Rosh Pinah, in order to accommodate the growing ventilation demand. This entailed an evaluation of all the feasible alternatives available to improve air flow to the working faces (Mukherjee et al., 1982). The current distributions of air flow, pressure, leakages, and air quality throughout the main flow paths of the WOF were quantified by conducting a pressure-quantity survey. Survey data was used to identify ventilation inefficiencies along the WOF drives and also to simulate the current ventilation network. Finally, the ventilation network and regulators were modified in order to distribute sufficient fresh air at the working faces in the WOF with minimum cost. VentsimTM software was used to simulate the ventilation network.