A borehole extensometer is a type of geotechnical instrument that is used to measure the stability, movement and behaviour of rock masses and soil within and adjacent to mines. Basically, they work by measuring the position of an internal rod relative to a reference/anchor point (or “head”). This information is then read from the device by mechanical/manual means (older technology) or electronically (up-to-date technology).

A multi-point borehole extensometer is so named because it can simultaneously monitor multiple reference points. This makes for more accurate and useful readings.

To keep the risks of mining at a minimum, it is necessary for mine engineering staff to constantly monitor the status and possible movement of soil and rock formations inside the mine. Any displacement can be a warning of an imminent collapse. When such movement is detected, mine engineers can take appropriate action, helping to save lives, safeguard equipment and prevent productivity disruption and delays.

Multi-point Borehole Extensometers are a critical part of safety monitoring within any mine, as they provide a lot of the data used by mine engineering staff and management to determine where intolerable risks exist.

The SMART MPBX from Mine Design Technologies (MDT) is a lightweight, flexible multi point borehole extensometer that simultaneously reads from six reference (anchor) points. Information gathered from the multiple anchor points is made available via an integrated electronic readout head.  The SMART MPBX is so compact that it can fit into a borehole with a diameter of only 2 inches (50mm). In fact, multiple SMART MPBXs can even be installed in the same long borehole if required.

Click here for specifications and more information about the MDT SMART MPBX.