Mines and open-pit quarries are considered particularly challenging deployment sites – not only for humans and machines but also for the measurement technology used. This makes robust and reliable instruments even more important when it comes to safety-related applications such as groundwater monitoring.
Australia possesses around ten percent of the world's coal reserves and is a leading exporter of this raw material. Dewatering plays a crucial role in coal mining: during extraction, the activities significantly affect the natural groundwater layers – creating so-called drawdown cones, through which water continuously seeps into the open pits. To ensure safety and operational continuity, this water must be pumped out continuously. Therefore, precise monitoring of the groundwater level is essential.
An Australian open-pit operator approached STS with a specific requirement: a pressure transmitter for level measurement up to 400 meters deep was needed – including a correspondingly long cable connection. The previously used solution (ATM.ECO/N/Ex) did not fully meet the requirements, as it was only specified for up to 250 meters cable length and a pressure range up to 25 bar.
Thanks to STS's specialization in custom solutions, a rapid response was possible. Within a few weeks, the new intrinsically safe pressure transmitter ATM.1ST/N/Ex was developed – precisely tailored to the requirements of the Australian open-pit mine.
The result: a reliable transmitter with a measuring range up to 40 bar (400 mH₂O), EX approval for use in explosive environments, and a 400-meter-long Teflon cable. The latter was deliberately chosen over softer PUR due to its chemical resistance and shape stability.
Additional features include:
Screwed ballast weight for stable positioning in the medium
Stainless steel strain relief, also screwed, to protect the cable management
Sealed cable gland and open vent pipe
Technical Data of ATM.1ST/N/Ex Overview
Measuring range: 1…250 mH₂O (optionally up to 400 mH₂O)
Accuracy (characteristic curve): ≤ ±0.1 % FS
Total error: ≤ ±0.3 % FS (-5…50 °C)
Temperature range: -5…80 °C (operation and medium)
Output signal: 4…20 mA
Materials: Stainless steel, titanium
Certification: EX-approved
Flexible process connections available on request
With the ATM.1ST/N/Ex, STS has once again demonstrated how flexible and quick response to demanding customer needs can be. The tailored transmitter is now used in Australian coal open-pit mining for safe and reliable level measurement – even 400 meters below the surface.