Mine Surveying Applications
This page contains useful information about Wall Stations. Select a topic from the list below to read more.
Wall stations use resection (sometimes referred to as free station) to position the instrument. Resection is dependent on the accurate positioning of the reference points observed. Underground wall stations involve the continuous use of resection to position the instrument and coordinate new stations. Any error in wall movement is magnified as you traverse along.
Mines with soft or fluid ground are usually not suited to the practice of wall stations. Conventional stations installed in the backs (roof) of these mines may move but usually only in a downwards direction which results in minimal errors horizontally. Wall stations installed in soft (squeezing) walls can move horizontally, having a dramatic effect on the running bearing (azimuth) of a heading, resulting in large positional errors.
If you are unsure what the ground at your mine is doing, then the best thing to do is test the ground by monitoring it. This can easily be achieved by placing wall stations on opposite walls in different locations. Then measure the distance between the stations over a period of time to see what distances the walls are moving (squeezing). Speak with the Geologists and Geotechnical staff at the mine as they should know and understand what the rock is doing. It might be the case that a particular rock exists only in certain areas which can be avoided with wall stations. It may also be the case that the majority of the stoping or development is in this type of ground. The decision to use or not use wall stations is always the Authorised / Registered Surveyors on site.