ABSTRACT: Accurate and timely monitoring of strata stability in underground excavations is a critical activity that forms part of the fundamental daily mine safety processes and is mandated by law to be carried out in all operations. Coal mine strata monitoring includes the use of instrumentation and observations carried out by personnel. Mechanical tell-tales are an instrument widely used throughout the coal mining industry and are used to measure displacement of roof rock horizons. They comprise of either 2 or 4 reading indicators that are connected by stainless steel wires to anchors secured up a purposely drilled hole and require personnel to read them individually and record displacements manually.
Prompted by the desire to improve safety and provide a system that could offer continuous monitoring of areas within the mine, without the requirement for manual recording of tell-tale data, Moranbah North Mine (MNM) initiated installation of a remote reading monitoring scheme in 2012. The monitoring system is entirely automated, and the data is automatically collected and transferred to the surface via an optical fibre cable. Alarms are pre-set to defined triggers and alerts are sent out automatically if triggers are reached. The real time data can be accessed anywhere with available internet connections and log on details. Significant amounts of data, previously not accessible, has been recorded and collected since the initial remote reading system was installed. This has provided critical information for support design work, remedial works, and development of accurate Trigger Action Response Plans (TARP). The data is increasingly being used for optimising mine support. Upgrades to the remote reading technology in recent time mean that the available system uses cutting edge technology and can be manipulated to meet different applications.
All Anglo American underground metallurgical coal mines within Australia now employ Remote Reading Tell-Tales (RRTTs) in longwall gate roads. The system is also being adopted by numerous other coal mines in other mining groups both in Australia and Globally