ACE has developed an underground dewatering system that increases residence time and water removal capabilities.
Respirable dust is a constant underground obstacle, particularly in coal mining operations where dust particles are often so small they’re not visible to the naked eye.
As a solution, mining companies commonly introduce more water to suppress the dust and manage the health risks. However, this approach increases material degradation and the risk of spillage issues, and traditional fixed dewatering systems are often ineffective at removing large quantities of the suppressant.
Enter the new vibrating screen dewatering system from Australian Conveyor Engineering (ACE).
ACE senior mechanical engineer Taylor Jobson said the dewatering solution looked to improve one important concept.
“If you speak to people in mineral processing or coal preparation plants, it’s all about the residence time, so how long you have the material in that piece of equipment. The more time you have it there, the more opportunity you have to influence the product,” Jobson said.
“If you think about a normal transfer, you might have half a second to a second of residence time in that transfer. So you don’t have a lot of time to do any dewatering in a traditional sort of system.”
ACE has manufactured a dewatering system that increases residence time and increases the opportunity for water removal as a result. This is done through a staged process.
“Firstly, we focus on the portion of the product that has the highest amount of water,” Jobson said. “As material is conveyed from the feeding point to the transfer, the water sinks to the bottom.
“As that goes over the transfer, we cut that material off. We have a hydraulically operated cutter blade that opens and captures the bottom portion of the material. It’s a relatively small portion but it has the highest amount of water content because it’s all sunk to the bottom.”
The second phase of the dewatering system sees the isolated material move into a screw conveyor where it is removed from the transfer to be handled and processed on a vibrating screen.
“(With this system), when the material is on the vibrating screen, it’s spending more time there – instead of one or two seconds, it’s spending five to 10 seconds on that screen, or maybe a bit longer,” he said.
“This means there is much more opportunity and more time to dewater that product before putting it back onto the belt.”
Increasing residence time in underground environments has typically been a difficult task primarily because of the space constraints.
ACE has designed the vibrating screen dewatering system with the confines of an underground environment in mind, while the equipment can also be retrofitted onto an existing conveyor. This saves mining companies the extra costs of accommodating the system through the excavation of larger underground chambers or other alterations.
Jobson said the system’s water control capabilities have improved the safety and efficiency of ACE’s underground coal mine customers in New South Wales.
“One of our installations in NSW, whenever the conveyor is restarted, the customer ends up with 100–200m of belt that’s full of water,” he said.
“This creates personnel hazards because it’s not really designed to move water. Then you have to deal with thousands of litres of water on this system and the receiving system.
That was one of the key things this customer was dealing with – that initial start-up moisture – but this new system is able to capture that water and divert it straight into a sump.”
As part of Fenner Conveyor’s group of companies, ACE has its own in-house engineering team to customise the system as needed, along with the service capability to attend to any post-installation tweaks or requests.
Through the success of ACE’s early installations, this new technology is being adopted by mining customers across the east coast, with systems now also in development for various Queensland sites.
Jobson said the system was not only applicable to underground coal mines, but also suited to any mining conveyor that has moisture or water issues.
This feature appeared in the June issue of Australian Mining.