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Optimisation rules set in the Flow Optimisation step tell the software user’s display preferences (grades, blends, tonnes) when calculating destinations and product handling.
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Overview
Flow rules are used to determine the best destination for material at each time step. The best destination is defined as the one yielding the highest positive cash flow, where the cash flow is the sum of all rewards and penalties.
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Rule Calculation Type | Behavior |
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Instantaneous | Target is evaluated for every instant in time. |
Stockpile | Target is evaluated over the complete build of target stockpile. |
Period | Target is evaluated over the entire period duration. |
Typically, a destination will be assigned at least one positive cash flow (reward for sending material), as well as several grade targets (penalties for going off-spec). The optimiser then sieves out a selection of blocks that (if possible) yield high rewards and low penalties.
Destinations with a net negative cash flows are discarded. For example, the crusher may decide not to feed material if the grade penalty outweighs the reward for movement.
Adding Flow Optimisation rule
To add the optimisation rule, press the Add Item button and select a type from the dropdown.
Name the rule clearly. Avoid using commas in the Flow Optimisation rule name, otherwise you will get an error message preventing you from going past this step:
<The name of (…), is invalid>.
3. Toggle the Enabled flag to enable or disable usage of the Flow Optimisation rule.
4. Click the field in the Optimisation Item column to customise the optimisation rule. Once completed, the configuration field will list all of the populated fields.
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Rule Types
Cash Flows
Cash flow rules define a dollars-per-unit rate on material types conveyed between sources and destinations. Once a rule is configured, the rate is specified in the calendarCalendar.
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Configuration Item | Description |
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Input Method |
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Arrows | The destination(s) to which the cash flow is applied. |
Fields | Separate cash flows are added for each checked field. |
Sources | Filter the sources to which the cash flow is applied. |
Parcels | Filter the parcels to which the cash flow is applied. |
Agents | Filter the agents to which the cash flow is applied. |
More details and examples of CashFlows see here.
Max Rate
Max Rate limits the optimiser to a specific rate for an instant in time.
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Configuration Item | Description |
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Input Method |
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Arrows | The destination(s) to which the max rate is applied. |
Fields | The field to which the max rate is applied. |
Sources | Filter the sources to which the max rate is applied. |
Parcels | Filter the parcels to which the max rate is applied. |
Agents | Filter the agents to which the max rate is applied. |
Plant Agent
The Plant Agent is appearing by default in the list of Agents when configuring Cash Flows, Max Rates and Max Quantities.
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The Plant Agent controls Post Crusher movements, that are not covered by Destination rules, but drawn manually in the Flow Chart step. |
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Grade Targets
Grade targets penalise the optimiser for going off-spec. The optimiser balances between positive cash flows and negative grade penalties to match blocks to destinations.
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Configuration Item | Description |
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Input Method |
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Arrows | The destination(s) to which the max quantity is applied. |
Fields | The field to which the max quantity is applied. |
Sources | Filter the sources to which the max quantity is applied. |
Parcels | Filter the parcels to which the max quantity is applied. |
Agents | Filter the agents to which the max quantity is applied. |
Plant Agent
“What is PlantAgent and what is it used for?”
The Plant Agent is appearing by default in the list of Agents when configuring Cash Flows, Max Rates and Max Quantities. It is not being involved in the Expit movements, so it does not matter whether it is checked or not in the optimisation rules configuration for mining and rehandling.
Since the PlantAgent is not involved in any Expit movement, it won't consume any haulage units' hours, and doesn’t require being assigned in the Trucks Assignment step.
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Flow Chart
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The Plant Agent controls Post Crusher movements, that are not covered by Destination rules, but drawn manually in the Flow Chart step. |
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Transactions performed by the PlantAgent are controlled by the optimization rules in the Calendar. This sort of control is optional. If not controlled in the Calendar, it will default to the upstream or downstream site items rates.
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Note
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In the example below, when reducing the PlantAgent’s max rate to 1000wt/h vs 5000wt/h Crusher’s rate, it creates bottleneck at the Crusher downstream since the Stockpile is getting filled faster than can be reclaimed to feed the Crusher:  | ||
It causes reduction of the material being fed to the Crusher upstream to allow for the Stockpile reclaiming at the reduced rate:  | ||
In the Destinations tab it is also visible that the stockpile is being built faster than could be reclaimed:  |
Reporting
Filter by the “PlantAgent” Agent in the Pivot report to see all material movements it controls:
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Steady States
Plant Agent is not involved in expit movements. To check the transactions that it performs at a particular point in time, go to the Steady States tab.
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