The underground environment is a harsh and hazardous workspace for plant and personnel. It is damp, dusty and hot, there is a risk of roof and rock falling and the atmosphere can be potentially explosive. Recent incidents are a reminder of how crucial safety is in mining. The increasing miniaturization of RF devices and microelectromechanical systems (MEMS) and the advances in wireless technologies have generated a great deal of research interest in the area of wireless sensor networks (WSN). Sensor networks provide a promising infrastructure for gathering information about parameters of the physical world. Such networks have many applications in military and civilian environments. In this paper, a new wireless sensor network architecture is introduced for surveillance and security monitoring of underground mines and confined areas.