Australia is home to some of the largest iron ore deposits in the world, mainly consumed by Chinese steel mills. Not long ago, one of the mining companies failed to meet its export targets, resulting in a supply shortage. As a result, the mine launched an investigation to identify and eliminate any bottlenecks. Every process was examined in detail – from blasting, the feed into the main plant, the set-up of the crushers, the operational parameters that were implemented in the area, to the loading of iron ore onto the trains that transport the raw material to the ports. A problem area the team discovered was unreliable level checking of the ore in the crushers.
VEGA Australia has been working at the plant for many years and has always provided the impetus to introduce a new technology. In 2004, the company introduced the first radar level sensor for bulk solids – the VEGAPULS 68. These instruments were installed in the entire site at that time. VEGA was also approached with the current requirements for process optimisation.
To find a solution to the problem, VEGA investigated the secondary and tertiary crushing processes. They found the sensor could not follow the level during fast filling and emptying processes. In addition, the wide opening angle of the existing sensors resulted in considerable interfering reflections, which repeatedly led to incorrect measurements. The customer was then shown the latest development in radar technology, the 80 GHz radar sensor, which was launched in 2016 promising a significant potential for improvement in these applications.
In radar technology, the width of the beam is determined by two factors: the operating frequency and the diameter of the horn antenna. The devices installed so far worked with 26 Gigahertz and had a horn diameter of 95 mm, which resulted in a beam angle of 8°. This repeatedly led to the situation where the crusher was being detected instead of the ore.
With the VEGAPULS 69, the transmission frequency is 80 Gigahertz. This allows a beam angle of 3,5°, an improvement of more than 50%. There are also improvements in the speed of response from the new instrument, allowing it to keep up with the fast-changing level of the ore inside the chamber. VEGA Australia initially supplied some test instruments and supported the customer during setup after installation.
Many measures led to the goal
The result was immediately apparent. Thanks to the new measuring device, more reliable level control was achieved. The more precise focusing led to a huge improvement and the false return echoes from the main chambers of the crusher were eliminated. The devices were tested and the results were compared with the originally installed devices, The VEGAPULS 69 performed superbly. Even though the units were replaced with the latest radar technology, an easy transition was achieved because the basics remained the same.
Conclusion and outlook
Upgrading the level sensor was not the only measure taken at the site to increase efficiency. Many other items of site equipment were also improved or replaced and other system components were fine-tuned and matched to each other. The result was impressive – an increase in production of over 700 tons per hour.
Since then, the Australian mining company has implemented these improvements in all its operations in the region. The VEGAPULS 69 has been instrumental not only in solving the specific problem, but also in improving operations generally.
For VEGA, these examples of customer requirements are at the core of its commitment to research and develop sensors to meet not only current application challenges but also implement features that will handle others as they become evident. As industries move into the future, suppliers such as VEGA need to respond with solutions to meet an ever growing and changing market.
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