Author: Douglas Morris
One of the most ubiquitous operations in any mine is the use of hydrocyclones (cyclones) in the comminution circuit to sort particle sizes for mineral processing. Downstream of this process is the flotation circuit, which can be adversely affected if there is an upset with cyclones. Poor cyclone performance will impact recovery, grade, and will reduce mineral processing throughput.
The fundamental problem with operating cyclones is that they are very sensitive to process changes yet are poorly automated and instrumented. As a matter of fact, most mines rely on visual inspection of the cyclone outlet to determine if operations have gone askew. Because of this visual inspection, most often there is a delay in detecting a problem, which reduces the effectiveness of flotation because large particles (course) are sent to flotation, which the process cannot use.
Roping and plugging are the most common operational issues. The former occurs when too many solids are discharged out the cyclone overflow and it looks like a rope is being discharged from the underflow. Plugging, on the other hand, is a situation where something is stuck inside and there is no separation taking place. This is the worst-case scenario because all the material within the cyclone is sent along to flotation. If undetected for too long, plugging will result in a flotation cell having to be shut down so that all this extra material can be physically removed (think workers using shovels for extended periods).
Traditional methods for detecting roping and plugging are many but the most popular technologies used are acoustics or ultrasonics. Although a step in the right direction, their ability to consistently detect roping and plugging events is inconsistent. A better approach is to deploy Emerson’s vibration technology that has proved to be a very reliable means for quickly detecting both roping and plugging events.
Emerson’s alliance partner, Portage Technologies, has effectively deployed such a solution at Copper Mountain located in Princeton, British Columbia, Canada. This mine implemented the Portage Cyclone Detection (PCD) solution to alert the control room of roping and plugging incidents so that corrective action could be taken within seconds, rather than minutes. A total of 32 sensors (2 per cyclone) were installed on the mine’s cyclopacs.
PCD was commissioned at Copper Mountain in August 2014 and has resulted in a significant reduction in response time for roping and plugging events. Prior to this system, it took operators an average of ten minutes to respond, but now the typical response time is reliably less than one minute and often within seconds. Since implementation, on average PCD has helped operators identify and respond to several roping and plugging incidents per week. In addition, the mine has seen a drastic improvement of the availability of their on stream analyzer that previously was often unavailable from being exposed to too much material from roping and plugging incidents.
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