Some industries, such as the mining industry, face the challenge of having to measure the level of solids. Unlike liquids, they must content with the peaks and valleys depending on the consistency of the solids being measured.Emerson’s Asael Sharabi shared a story with me about a Canadian copper miner. In their mining process, they crush five different types of ore. The raw ore is passed through a crusher and the crushed ore is stored in the ore pass/underground silo.
The trouble was that they were experiencing excessive maintenance costs and availability issues caused by the daily wear and tear on the crusher, specifically to the ore pass. The damage to the ore pass is caused by the ore falling directly onto the trap door at the bottom of the pass, known as a press frame. This press frame is coated with a rubber liner to reduce the force of impact from the falling rocks. In their mining operations, these were wearing away the liner very quickly and damaging the press frame.
The falling rock could also escape the ore pass and damage nearby lighting, posing a risk to worker safety.Not only was the repair cost greater than $100,000, the associated downtime could be several days. The mining operations staff needed to source a level measurement that would measure down to the bottom of the ore pass that is 225 feet deep. Various level measurement technologies were tried with hopes of producing a buffer of stationary rock to act as a cushion. These instruments were not able to measure the level due to dust and the area dimensions.
Also, the buffer of rock meant there was too much ore in the pass and different grades of ore would be unintentionally mixed causing inefficiencies during processing.
After these attempts, the miner installed a Rosemount 5708 3D Solids Scanner on the top of the 225-ft ore pass. The transmitter was able to penetrate the dust and the sensor was able to measure right down to the bottom of the ore pass, avoiding the trap running empty and meeting the accuracy requirements. This ability to measure the lowest point helped to make sure that neither the line nor the press frame was exposed to the falling rocks.
This solution not only helped to improve worker safety and to avoid repair costs and associated downtime; it also helped to avoid the operational performance issues caused by the mixing of ores.