Over a 4-month period early in 2022, Aury Australia have been working with our South East Asian customer to solve their process issues. With travel restrictions there was a lot of email communication and some video conferencing. We hope to be back on site very soon.
Our customer was having issues with cone and jaw crusher breakdowns, pegging of screen media and unplanned shutdowns to either repair or clean screen media and/or crushers. These issues prevented the client moving forward with any plans for increased production.
Being the screen media is ahead of the crushers, they wanted initial help with their screen media. The media layout or design hasn’t changed too much since the process started over 8 years ago.
Photos were sent of what the decks would look like after a short period of operation, never getting better. Our customer persevered with this issue but were suffering from more frequent maintenance and repairs recently while wanting to increase production levels. These higher levels were not achievable in the current situation.
Top Deck (Before optimisation)
The screen has two decks. The top deck, while relatively unpegged, did have apertures along the fixing rails. It was clear that the rock size passing was too large for the fixing rail protection “wings” to pass resulting in the rock jamming (pegging) and then being filled with fines. This reduced panel open area from a design of 42% down to lower than -32%. Being an opposition type fixing rail with large protection “wings” used to protect stringer rails the solution needed to be innovative.
Bottom Deck (Before optimisation)
The second deck used a series of square apertures at different sizes down the screen. There were a total of 3 different aperture steps. Unfortunately, the pegging of apertures was quite severe.
The loading on the screen was not seen as an issue considering the aperture sizes but the fines presenting at the discharge was. The crusher issues were a result of these fines.
A PSD was sent to Aury. A meeting was organised to discuss the customers required size fractions according to their process limits. A few possible solutions were presented to our customer. These were discussed and refined. The solution for both decks was to install slotted apertures. On the top deck the apertures were moved in and away from the fixing rail protection strips while still maintaining the open area. On the bottom deck the apertures were staggered and 3 rows of 50mm high cross dams added to slow and roll the material. The open area was slightly improved.
The new panels were manufactured, delivered to meet the planned crusher service schedule and installed without issue. The photos show the decks 2 weeks post install. The feed end impact top deck panels still showing the same issue but they will be improved in the next round.
Top Deck (after optimisation)
Bottom Deck (After optimisation)
The instant result was our customer not experiencing any pegging and struggling to choke feed their crushers! This allowed them to try new things in terms of TPH, feeder rate increased and crushing sizes. Below you will see that the Amps consumed has lowered by 12%, their TPH have increased, and their recirculating load has dropped.
The opportunity to work with our customer has allowed them to save money in power by reducing the Amps from an average of 2.3Amp h/T to <1.7Amp h/T, even with a feeder speed increase. It has reduced their planned and unplanned shutdowns and increased available screening/crushing hours. It has allowed them to increase their throughput from an average of 400TPH to >500TPH while reducing their average recirculating load by approx. 24%. Our customer can now move their attention to other areas to improve efficiency. We thank their team involved. This was a great result for them.