Transfer chute flow analysis uses computer simulation to show how bulk material will move through a conveyor chute before the chute is built or changed. It shows where coal, ore or other material will build up and block, where liners will wear fastest, and where material will spill or land off-centre on the next belt. For a coal handling plant, port or mine, that means problems are found on screen rather than after commissioning, when fixing a chute is slow and expensive.
This guide covers what causes chute blockage, what a simulation tests, how adjustable chutes fit in, and the operating data that makes the results worth trusting. Kenomont works with companies in Australia and across Asia.
Why transfer chutes cause so much trouble
A transfer chute is a steel channel that guides material from one conveyor to the next, or into a bin, stockpile, crusher or ship's hold. When one goes wrong it stops the whole line.
Common problems include:
- Blockages. Material builds up in corners and dead spots until the chute chokes.
- Wear. Material hitting the same spot at speed wears through liners, which then need replacing.
- Spillage and dust. Material that leaves the chute off-centre spills over the belt edge, and fines become airborne.
- Belt damage. Material landing hard or at the wrong angle on the receiving belt causes wear, cuts and tracking problems.
Clearing a blocked chute means isolating the conveyor and sending crews in, which is slow, dirty and risky work.
What causes chute blockage in a coal handling plant
In a coal handling plant (CHP), chute blockage usually comes from a mix of the material and the chute, rather than one single fault. The common causes are:
- Wet and sticky coal. Moisture changes how coal behaves. Dry coal flows freely; the same coal with more surface moisture can stick to steel and to itself.
- Fines. Fine particles fill the gaps between larger lumps and, when damp, act like a paste that builds up on walls.
- Wet-season and monsoon conditions. Sites in India, Indonesia and northern Australia can see material that handles well for most of the year and then blocks repeatedly once the rains arrive and stockpiles get wet.
- High-moisture coals. Some coals, such as many lower-rank and sub-bituminous coals, carry more moisture by nature, so they are more prone to sticking even in dry weather.
- Poor impact angles. If material hits a wall or plate too square on, it loses its speed and piles up instead of sliding on.
- Build-up on walls. A thin layer of stuck material makes the wall rougher, so more material sticks, until the opening narrows and the chute chokes.
- Oversize lumps and tramp material. Large lumps, timber, rock or steel (tramp material) can wedge across a narrow section and start a blockage behind them.
Most get worse when a plant runs above its design throughput or handles a coal it wasn't designed for.
Why rules of thumb aren't always enough
Rules of thumb work well when the material stays the same. They work less well when a site handles several coals or products, when wet seasons change how material behaves, when throughput is raised beyond the original design, or when a new layout changes the speed and angle material arrives at. A simulation shows those effects before they happen.
How the simulation works
The most common method is the discrete element method, or DEM (also called discrete element modelling). In plain terms, the computer models material as a very large number of individual particles and works out how each one moves, collides, slides and sticks as it falls through a 3D model of the chute.
To do that, the model needs to know:
- the shape and dimensions of the chute and the conveyors feeding it,
- belt speeds, belt widths and the rate material is moving (throughput),
- particle sizes and how they vary, and
- how the material behaves, including moisture, stickiness (cohesion) and how it slides against steel and liners (wall friction).
The material properties are usually set, or calibrated, from simple laboratory tests on real samples, so the simulated material behaves like the real thing. The output shows where material speeds up, slows down or stops. Engineers can then change the chute shape, add or move liners, or adjust flow aids, and rerun the model until the problem areas are gone. It's a virtual test before any steel is cut.
Transfer chute design: what a DEM simulation tests
A DEM simulation is most useful when it answers specific transfer chute design questions. The ones we look at most often are:
- Hood and spoon chutes. A hood catches the stream coming off the head pulley and turns it downward; a spoon at the bottom catches it again and places it on the receiving belt, moving in the same direction and close to belt speed. The simulation shows whether the stream stays together and slides along both, or hits and scatters.
- Impact and flow angles. Whether material strikes plates at a glancing angle and keeps moving, or hits square on and loses speed.
- Wall friction. Whether the chute walls are steep enough for this material, wet and dry, to keep sliding rather than build up.
- Liner choice and liner wear. Where material slides and rubs hardest, so wear-resistant liners can go where they're needed and chute liner wear can be predicted rather than discovered.
- Belt loading and centring. Whether material lands in the middle of the receiving belt, at a sensible speed and direction, so the belt tracks straight and isn't damaged.
- Dust and spillage. Where the stream breaks up, where fines escape, and where skirts and seals will be tested.
The same questions apply to transfer point design generally, whether the chute feeds another conveyor, a bin, a crusher or a shiploader.
Adjustable and regulating chutes
Some transfer points use adjustable or regulating chutes: a flap, gate or deflector plate that can be moved to direct material, split the flow between two belts, or change where the stream lands. They're common where a plant handles different coals, or where one conveyor feeds several destinations.
The difficulty is knowing where to set them. A flap angle that works for one material or throughput may cause build-up or off-centre loading for another. A chute flow simulation can be run at several flap positions and throughputs to show which settings keep material moving and land it centrally, and where the limits are. That gives operators settings based on evidence rather than trial and error on a running conveyor.
The results are only as good as the inputs
This is the part that often gets less attention than it deserves. A simulation of the wrong material, or the wrong throughput, gives a confident answer to the wrong question.
Good inputs come from good operating data:
- Throughput records. Actual tonnes per hour, including peaks, not just the design figure.
- Product records. Which coals or products pass through the chute, how often, and in what conditions.
- Moisture and weather. How wet the material is at different times of year.
- Stoppage and maintenance history. Where and when blockages happened, and how often liners were replaced.
At many sites this information sits in several places: weighbridge systems, control system logs, maintenance software and spreadsheets. Pulling it together before a chute study saves time and makes the results much more trustworthy.
Once a new or modified chute is running, the same data shows whether it's working: fewer blockages, longer liner life, and the line holding its rate in the wet season.
Where Kenomont fits
We have built transfer chute flow simulations ourselves: modelling how material moves through a chute, showing where it builds up or wears, and testing changes in the model before anything is fabricated. The final chute design, fabrication and sign-off stay with your engineers. We work remotely, so the location of the plant doesn't matter: we work with companies in Australia and across Asia, using drawings, belt data and material information supplied by the site.
Alongside the simulation work, we've built and supported a woodchip export port management system for Australian forestry export companies since 2012. Since 2015 it has received weighbridge ticket data after weighing, and it feeds executive reporting dashboards. We are also building a shiploader flow simulation tool for testing throughput and loading-rate what-ifs.
That work is about getting throughput, weighbridge and maintenance data out of separate systems and into reports people trust. See our forestry industry page and business intelligence and reporting for more.
Frequently asked questions
What is transfer chute flow analysis?
It's a computer simulation of how bulk material moves through a transfer chute. It shows likely blockages, wear points and spillage before a chute is built or modified.
What causes chute blockage?
Usually a combination of the material and the chute: wet or sticky material, fines, high-moisture coals, wet-season conditions, walls that aren't steep enough, poor impact angles, build-up on walls, and oversize or tramp material wedging in narrow sections.
What is DEM?
DEM stands for the discrete element method, also called discrete element modelling. It models bulk material as many individual particles and calculates how they move and collide inside a 3D model of the chute.
How is DEM used in chute design?
Engineers build a 3D model of the chute and conveyors, set up the material from test results, and run it at real throughputs. The simulation shows where material slows, builds up, wears liners or lands off-centre, and design changes are tested in the model before steel is cut.
What is a hood and spoon chute?
A transfer chute with two curved parts. The hood catches material coming off the head pulley and turns it down; the spoon catches it again and places it on the receiving belt, moving in the belt's direction. Done well, it reduces impact, wear, dust and spillage.
What information is needed for a chute flow study?
Chute and conveyor geometry, belt speeds and widths, actual throughput, particle sizes and material behaviour, especially when wet. Real operating records beat design figures alone.
Can simulation fix an existing chute that keeps blocking?
It can show why it blocks and test changes first, such as a different shape, new liners, a changed flap setting or flow aids.
Can you simulate a chute for a coal handling plant outside Australia?
Yes. We work remotely, using the site's drawings, belt and conveyor data, and material samples or known material properties. We run the simulation and report the results; final design and sign-off stay with the site's engineers.
Does Kenomont do chute flow simulation?
Yes. We build transfer chute flow simulations and can bring your weighbridge, throughput and maintenance data together to show how the chute performs once it's running.
Talk to us about a chute or your operating data
If you have a chute that blocks, spills or wears faster than it should, or your throughput and maintenance data is spread across separate systems, we can help: a flow simulation to test changes before you make them, and your operating data in one place so everyone works from the same numbers. Email [email protected] or use the form to book a free initial chat, wherever your plant is. Callers in Australia can also ring 1300 470 091.