SENSOR SOLVES BOTTLENECKING PUZZLE

the current level during rapid 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. Upon further investigation, it was found that relocating the installed units to improve performance would only lead to other issues. The customer was then shown the latest developments 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 GHz and had a horn diameter of 95 mm, which resulted in a beam angle of 8 degrees. This repeatedly led to the situation where the crusher was being detected instead of the ore.

Recently, an Australian mining company failed to meet its export tonnage targets, resulting in a supply shortage for its customers – a costly situation for all concerned. As a result, the mine launched an investigation at one of its main sites to identify and eliminate any bottlenecks.

Every process was examined in detail – from the first blasting, feed into the main plant, setup of the crushers and operational parameters implemented in the area, to loading the iron ore onto the trains that transport the raw material to the export ports. One problem area the team discovered was an unreliable level-check of the ore in the crushers.

Troubleshooting

Working at this particular plant for a long time, Vega has always provided the impetus to introduce new technology. In 2004, the company introduced the world’s first radar level sensor for bulk solids, the Vegapuls 68, which it installed across the entire site at the time. Accordingly, Vega was approached again with the current requirements for process optimisation.

To find a solution to the current problem, Vega investigated the secondary and tertiary crushing processes, finding that the sensor could not follow

With the Vegapuls 6X, the transmission frequency is 80 GHz, which allows for a beam angle of 3.5 degrees –an improvement of more than 50%. Improvements in the speed of response from the new Vegapuls 6X would also allow for the transmitter to keep up with the fastchanging level of the ore inside the chamber. So, Vega initially supplied some test instruments and supported the customer during setup after installation.

Huge strides

The result was immediately apparent. Thanks to the new measuring device, a much more reliable level of 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, leaving only a measurement from the medium inside. The devices were tested and the levels recorded over three months. The results were compared with the originally installed devices, and the Vegapuls performed superbly. Even though the units were replaced with the latest radar technology, the basics of radar technology have always remained the same, thus allowing for an easy transition in installation and programming.

Other parts of the site equipment were also improved or replaced and various system components were finetuned and newly matched to each other.

The result was impressive: what initially began with a temporary drop in performance of up to 40% was improved to a worst-case scenario of only 3%, which led to an increase in production of over 700 tph. The Vegapuls was instrumental in not only solving the problem but in improving overall operations.