A coal-loading tipple receives coal, routes it through handling or sizing equipment, and loads it for transport. The rotary-dumper variant shown here restrains a railcar in a rotating barrel, empties it into a receiving hopper, then returns it to the track for exchange.
Coal-loading Tipple Interactive Calculator
Set payload per car, the complete operating cycle time and operating availability. Compare capacity while cycling with estimated average hourly throughput. The diagram follows a restrained rotary car dumper through tipping, return and exchange.
Equation Used
- US short tons throughout.
- One payload per complete operating cycle.
- Availability applies to scheduled time, not material yield.
- No downstream capacity limit or material loss calculation.
Rotary-dumper variant. Whole-car restraints and platen rotate together. Stage timings, coal level and falling material are schematic, not control or granular-flow predictions. Availability represents time only; reduced capacity is not mass loss.
Follow the car, barrel and material route
The end view looks along the track. The car stands on rails attached to the rotating platen, inside a barrel supported by trunnion rollers. The clamps close against the car before rotation. The car, rails and clamps rotate together; the hopper and conveyor remain fixed below.
After discharge the empty car returns upright and the clamps rise. Car exchange occurs along the track, into or out of this view. The exchange stage is labeled while the car moves along the track, perpendicular to this end view. Coal falls toward the receiving hopper; the conveyor represents the route to screening and loading downstream.
The animation uses a 160° example rotation, a simplified sequence and equivalent idle time after each operating cycle. It runs eight times faster than the entered time. These stage proportions, fill shape and material flow are illustrative; they do not specify actual dumper controls or granular-flow behavior.
Mechanism references
Metso describes the positioned railcar, rotating barrel, clamps, hopper, conveyor and return cycle. The National Park Service’s Blue Heron account shows that other tipples used bottom-dump cars feeding screens and chutes. A tipple is a handling plant, not one universal dumping mechanism.
Rotary dumping within a handling plant
Rotary dumpers handle bulk railcar loads including coal. A tipple can also receive bottom-dump cars, trucks or other incoming transport. The receiving arrangement and downstream plant determine the actual process.
This calculator is a per-car timing model. It does not determine the screen, crusher, storage or loading capacity needed downstream. The layout illustrates a rotary dumper rather than a particular historical mine.
Operating capacity and average throughput
Let M be payload in US short tons per car and t the complete cycle time in seconds, including positioning, dumping, return and exchange while the plant is operating. Then cars per operating hour = 3600/t and operating capacity is 3600M/t short tons per hour.
Let a be the fraction of scheduled time available for operation. Estimated average throughput is a × 3600M/t. The difference from full operating capacity is an hourly rate reduction, not discarded coal. The equivalent average interval between cars is t/a.
Availability here represents time, not screening yield or a mass-recovery fraction. Do not count the same downtime both inside the entered cycle time and in availability.
Worked timing example
At 50 short tons per car and a 90 s complete operating cycle, capacity is 40 cars per operating hour or 2000 short tons per hour. At 60% operating availability, estimated average throughput is 1200 short tons per scheduled hour.
The difference is 800 short tons per hour of unused capacity. It does not mean 800 tons of coal are lost. The equivalent interval is 150 s per car: 90 s operating plus 60 s downtime, averaged across repeated cycles.
What the timing model can establish
A larger payload raises mass throughput at the same car rate. A longer cycle reduces car rate and mass throughput. Lower availability reduces the average rate without changing operating capacity.
The model assumes the receiving and downstream equipment can accept the average flow. It does not calculate peak hopper discharge, screen blinding, product yield, drive torque, structural loads or contractual production. Use measured cycle and availability data for a plant estimate; displayed dimensions and ranges are illustrative.
Tipple calculator questions
What does availability mean here?
The percentage of scheduled time spent operating at the entered complete cycle time. It is not the percentage of coal recovered after screening.
Why does the car-rate output not change with availability?
That output is cars per operating hour. Average mass throughput includes availability; operating capacity does not.
Is the rate reduction coal waste?
No. It is unused hourly capacity due to the entered time allowance. Material recovery needs a separate mass balance.
Why does the car stay attached when upside down?
The car is restrained by clamps and the rail platen inside the barrel. The clamps remain closed through rotation and return, then open with the car upright.
Are all tipples rotary dumpers?
No. Different tipples receive material in different ways. This illustration selects one rotary-dumper arrangement.
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