Electricity + Control March 2019

TEMPERATURE MEASUREMENT round up

Open-pit mining in diamond deposit

The Grib Mine, located in Russia’s Mezensky District in the Arkhan- gelsk Oblast, is one of the largest diamond deposits in the world. During winter, temperatures can reach -25°C (sometimes even as low as -37°C). The ‘Arhangelskgeolrazvedka’ exploration crew bores wells and monitors underground water levels and temper- ature. Keller – represented in South Africa by Instrotech – has equipped the wells with water level monitoring systems. The use of automatic water level monitoring systems allows for savings on special-purpose vehicles as well as additional staff, who would con- duct manual monitoring in remote and hard-to-reach wells. Saving on special-purpose vehicles and additional staff Water level and temperature are monitored within a radius of 5 km around the deposit area. Between 2011 and 2014, a total of 81 wells (with depths of 20-270 m) were bored in order to moni- tor water levels. The wells are equipped with 81 Keller water level monitoring systems comprising PAA-36 X W hydrostatic pressure (level) and temperature probes, as well as 59 GSM-2\GSM-2 BOX modules for automatic data registration and transfer by GSM.

Installed GSM-2 box As long as the monitoring net consists of cluster water wells, it is possible to use just one GSM-2 BOX module to register and transfer data from two to three wells placed at a distance of 5-10 m in the same cluster. It allowed the mine to reduce the num- ber of GSM-2 modules required for monitoring 81 water wells, from 81 to 59. Thus the mine could buy 22 GSM-2 modules few- er than anticipated, an approximately 15% saving on monitoring equipment for the project. The battery of a GSM-2\GSM-2 BOX module is able to supply several level probes. The module on the other hand can register and transfer data once a day in a low tem- perature environment (-25°C to -35°C) with a low-level or unstable GSM-signal for a few years. Interestingly, for the duration of the exploitation period (2011-2015), the mine did not find it necessary to change the equipment batteries. Enquiries: Instrotech. +27) 010 595 1831 or email: sales@instrotech.co.za

The Grib Diamond Mine, Mezensky District, Russia.

Installation of the level tubes in hard-to- reach locations.

Installed Keller GSM-2 box.

Heavy-dutyTrue-RMS Multimeter

A True-RMS-meter can measure both pure waves and non-si- nusoidal waves more accurately. Nonlinear loads, such as variable speed drives or computers can distort waveforms and an average responding meter can be as much as 40% lower or 10% higher in its calculations when measuring distorted waves. The battery-powered multimeter includes a Li-ion rechargeable battery that provides around six hours of operating time, and the ac adaptor to charge the system is included in the box. A low-battery warning will alert users when the voltage drops below the required operating voltage, and the MT1005 also offers an automatic pow- er-off function that the user can set to between five minutes and 30 minutes – or it can be disabled completely. With a wide range of features and double-moulded housing to ensure it handles tough conditions, the MT1005 is ideal for heavy-duty usage. Major Tech also offers a range of accessories for the device, from clamp on adaptors to additional batteries, leads and probes. Enquiries: Major Tech.Tel. +27 (0)11 872 5500.

The MT1005 is a heavy-duty True-RMS industrial digital multimeter for measuring ac/dc voltage and current, resistance, capacitance, frequency (electrical and electronic), duty cycles, diode testing, continuity and thermocouple temperature. The device is equipped with a large 50 000 count, 320 x 240

TFT colour LCD display and provides fast A/D converting sampling time, high accuracy, built- in data logging and trend capture functionality. It offers 4 mA to 20 mA process loop meas- urements with a percentage reading, and operates in a temperature range of -200°C to 1350°C. It traces any equipment interruptions and records the events on the device for future re- view. Not only does the MT1005 trace interrup- tions and record the events, it can also memo- rise datasheets and transfer this, and other data to a PC or a smartphone via Bluetooth.

36 Electricity + Control

MARCH 2019