Monitoring Coal Mine Runoff Using A Water Quality Data Logger
By: CAS DataLoggers
CAS DataLoggers provided a water quality data logger system for an open-cut coal mine to monitor the salinity of runoff water in local retention ponds. The water from these retention ponds could only be released into the local river system when it was of sufficient quality so as to have no effect on the irrigation supplies for the surrounding farming district. Therefore, it was necessary to closely monitor water quality in the lagoons for several key parameters including pH, salinity, and turbidity.
Mine management searched for a data logging system with the ability to connect to a wide range of sensors that was also capable of remote communications to allow convenient access to both recorded and real-time data. The data logger also had to offer low power operation so that it could operate off a solar panel since mains power was not available at the remote sites.
The mine operator chose a dataTaker DT82EM Environmental Data Logger to record the data from several sensors used to monitor the quality of the coal mine water discharge. The data logger was mounted in a weatherproof enclosure suitable for outdoor exposure at the monitoring site. The DT82EM was connected to a variety of sensors to allow measurement of conductivity (salinity), turbidity, pH, and water levels as well as thermocouples for measurement of the water and air temperature. A key feature of the logger was the ability to accept the output from many different types of sensors including analog signals such as voltage, 4-20 mA current, and digital signals such as Modbus RTU and SDI-12, the last being very common in water quality instruments.
For ongoing operations, data was uploaded via FTP twice a day using the internal cellular modem to a server in the mine's office. This was done to minimize power consumption by only powering the modem during the data upload. The downloaded data was then saved to a local database, allowing for data backup and long-term environmental monitoring. To observe changes in water quality in real-time during water management operations (such as mixing water from different sources or for mine water discharge monitoring), the logger was switched to a mode that continuously powered the modem.
The coal mine's water discharge monitoring operation benefitted significantly following the installation of the dataTaker DT82EM data logger, primarily by enabling the measurement of all the different types of water quality parameters. In addition, all of this data was made available through a single device.
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