KROHNE BM70A Level Radar helps saves lives

2003-Apr-01. Mining is fraught with hazardous processes and staying in control of the processes is a constant challenge for engineers and mine operators. The operational magnitude, sheer weight and mass of ore, dust and underground environments creates risks to personnel, mine infrastructure and equipment every passing moment.

One such hazardous process within a mine is the Ore Pass. These are shafts, sometimes up to 150m in depth. Ore is deposited by trucks into the top of the pass (known as the mouth) and held within the Ore pass by gates which are closed and locked in the lowest section of the shaft. Below these gates is a rail line. Upon opening the gates, the ore falls progressively into rail cars waiting underneath for transportation via an underground rail line for processing.

The risk is that sometimes, several tonnes of ore can remain ‘stuck’ in the ore pass upon filling the rail cars. A major hazard to personnel and plant equipment exists should the ore loosen and crash to the bottom of the ore pass after the train has departed. Ore Pass operators must somehow ensure that any ore that is deposited through the mouth of the pass is not left in the shaft after the last rail car has been filled.

One of Australia’s largest underground copper/uranium/gold mines came to KROHNE Australia to help solve this problem. KROHNE’s solution was to provide a non-contact level radar control device, the BM70A, in these passes which addresses all the problems above, plus increase the mine’s efficiency for this process. Due to the highly susceptible environment, it was discovered that KROHNE was the only radar manufacturer able to perform this measurement.

In these ore pass operations, a BM70A level radar has been (flange) mounted at the top of each ore pass and is used to monitor the level of the ore in the pass. The mine operators can ‘see’ the level of the ore gradually decrease when the rail cars are being filled. The BM70A will detect any ore that remains stuck in the ore pass allowing plant operators to take necessary precautionary action. Using the BM70A has further reduced the requirement to send inspection crews down the shaft to investigate the site of the blockage – thus preventing unnecessary risks to mine personnel.

The BM70A has been successfully installed for thirteen (13) ore passes within this mine. The level detection range for these ore passes is up to 120 metres. Further, remote programming of the BM70A and viewing of the process is made possible for mine operators through HART communications on the 4-20mA loop using KROHNE’s unique PC CAT software.
Louise Matthews.

Key words: Ore pass, level measuring, mining, hazardous, filling rail cars, level radar

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