TS. Schedule Logic Overview
Introduction
Keep these relationships in mind when making changes to the schedule logic and calendar values.
Item | Description |
|---|---|
Agent | Picks the blocks and executes schedule logic on them |
Dependencies | Only some blocks are available to mine at each moment |
Incentives | With the available blocks, prefer to mine some over others |
Destination Logic | With the selected block, find a destination |
Steps Logic | With the selected source and destination,
|
Fleets | With each selected fleet, find a truck and loader combination with remaining hours |
Loader Types | With the selected loader, consume loader hours at the loader production rate |
Truck Types | With the selected truck, consume truck hours at the truck production rate |
Once the sum of movement between a source and destination hits a Constraint, then no more material may be moved between those points.
In Optimise Products mode, once all constraints have been hit, the Product Specifications are used to recalculate the ore destinations for optimum crusher feed.
Once the destinations have been chosen, the following warnings may appear:
"Overflow" indicates that the optimised destinations use more truck hours than are available in the fleet.
"Optimisation Failure" indicates that the sum of mined ore is greater than the sum of capacities/constraints.
If either of these two warnings are encountered, the solution is to (a) mine less tonnes, or (b) travel shorter hauls, by changing the Constraints on mining and dumping in the Calendar.
Agents
An Agent executes the scheduling logic as individual schedule transactions, where a transaction is defined as moving an amount of material between a source and destination with a specific truck and loader.
Users may at times set up multiple agents to execute different, concurrent scheduling logic (such as ore/waste incentives, deposit1/deposit2 destination logic, AHS/Manual step logic, etc).
Dependencies and Incentives
In each period, each Agent filters the blocks by their dependencies, sorts them by their incentives, and selects the highest ranked available block.
Destinations and Constraints
The Agent selects the highest ranked block and checks for available destinations. If a block fails, it is removed from that agent's ranked block list (another agent may still try to mine it though).
In Optimise Products mode, ore destinations are only assigned at the end of the period. If the assignment exceeds the destination capacity constraint, then it returns an Infeasible Solution.
Steps Logic and Fleets
Once an Agent knows the source, material and destination, then it uses the Step Logic to look up the waypoints and fleet(s) for the transaction.
It may be a single step (such as pit ⇒ crusher) or multi-step (such as pit ⇒ stockpile ⇒ crusher).
Successive steps may utilise different fleets.
Equipment Matching
Once an Agent knows the fleet, then it picks the first loader/truck pairing with available hours remaining.
In Optimised Products mode, ore destinations are only assigned at the end of the period. If the assignment exceeds the equipment available hours, then the hours continue into Overflow.
Haulage
The Agent queries Haul Infinity for a cycle time for the given source, material, destination, truck, and loader.
In Optimise Products mode, ore destinations are only assigned at the end of the period. If the assignment fails due to no route found, then the scheduler will show an error message.
Issues
Summary of issues that may be returned by the schedule logic:
Scheduling Mode | Issue Type | Cause | Solution |
|---|---|---|---|
Optimise Products | Infeasible Solution | The optimiser could not find a destination for a material, either due to constraints or to product specifications. | Either reduce the ore mined or relax the capacities/constraints/grade limits that are constricting the movement |
Optimise Products | Invalid Cycle Time | Haul Infinity could not find a route. | Either there is no route in Haul Infinity, or the route contains steep segments/dynamic haulage |
Optimise Products | Overflow | The optimised destinations use more equipment hours than available. | Either reduce tonnage targets or reallocate equipment to shorter hauls |
Truck Constrained | Constrained by Steps Logic | If a step rule uses multiple fleets, both fleets must have available hours. | Either reduce tonnage targets or reallocate equipment to shorter hauls |
Constrain on Trucks | Stockpile reclaim defaults to zero | Calendar > Stockpiles > Reclaim Target = 0 | Manually set rehandle targets for each stockpile in each period |