Common questions from new and experienced users.
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Destination Logic describes the final resting place of material at the end of a period.
See Destination Logic.
What is Steps Logic?
Steps Logic describes all haulage between the Original Source and the Final Destination in a period.
See Steps Logic.
What are Constraints?
Constraints tell an Agent when to stop mining. The properties of the constraint are specified in the Setup; the limiting values of the constraint are specified in the Calendar.
See Constraints.
What are Product Specifications?
Product specifications tell the optimiser what tonnes and grades to send to each destination. The properties of the rules are specified in the Setup; the values of the rule are specified in the Calendar.
See TS. Product Specifications.
What is Overflow?
See TS. Overflow Warning.
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By adding a CrusherCashFlow with the stockpile(s) as the source, we are adding a decision variable to the objective function of the linear program which is used in determining what material to send to the crusher. The Cash Flow value required will be dependent on how other CrusherCashFlows have been configured. If two rules satisfy the same condition, then the cash flow is the sum of values in each rule.
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In the below image, it can be seen when the StockpileReclaim Cash Flow value is positive, the reclaim target, represented by the StockpileReclaimTarget constraint, is met.
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Standard Constraint - Long-Term Stockpile to Crusher
Limit: 1,761,749 dt
Actual: 1,761,779
Mined Blocks
Block 1 - 163,348
Block 2 - 219,126
Block 3 - 477,117
Block 4 - 314,729
Block 5 - 587,459
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As can be seen, the constraint is violated by 30 tonnes and happens with Block 4. The optimiser resulted in only 314,699 tonnes being sent to the crusher, leaving 30 tonnes behind. It is important to note that the crusher is the only destination where material from the stockpile can be sent. Typically, this would result in an infeasible solution; however, as outlined above, there is a .0001 tolerance for infeasible solutions. This means that if the remnant material is below the tolerance level, the block will be assumed fully mined. The tolerance level can be determined by multiplying the quantity mined by 0.0001. Using this logic, we can see that there could be up to 31 tonnes remaining of Block 4, 0.0001 * 314,729, before an infeasible solution is triggered.
