TS. Product Specifications

Overview

When the user presses the button to run one period in the Schedule, there are two passes happening behind the scenes.

The Product Specifications step allows the user to define the rules of the optimisation. Each rule becomes a new row in the Calendar. Values for the rule are specified in Schedule > Calendar > Product Specifications.

See below the description of each Product Specification type and their impact on the optimisation process.

Cash Flows

The chart above shows an example of the cash flow allocation for prioritising different ex-pit ore movements, namely:

• The reward for direct ore movement from the Pit to the Crusher is $100, which makes this transaction the most profitable and therefore prioritised by the optimiser.

• The reward for feeding a unit of high-grade ore from the Pit to the HG stockpile is $20, and medium-grade ore to the MG stockpile is $10, which prioritises moving of the high-grade over medium-grade material.

• Similarly with the reclaiming of HG and MG stockpiles: since the reward for feeding the Crusher with high-grade material is higher than that for feeding the medium-grade, the HG stockpile will be given greater preference to reclaim.

• Finally, the mineralised waste movement is the least profitable in comparison to ore flows, but may still be applicable in some periods, such as when high and medium grade ore is not available. If a negative cash flow is placed on this movement, feeding mineralized waste to the Crusher will be penalized because, for example, it may cost more in resource usage (machinery hours, fuel consumption, etc.) than will be received after processing a unit of this type of material.

Stockpiles and Crushers Cash Flows

Cash Flow rules for Stockpiles and Crushers 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 Calendar.

• Set the Source(s), Material(s), Destination(s), and unit (Quantity Field) on which to apply the Cash Flow.

Cash Flows by Plant

The example below allows the user to control the priority of the Wet plant and Dry plant, and prefer certain materials into each plant.

• $30 reward per railed tonne from the Dry plant.

• $30 reward per railed tonne from the Wet plant.

• $10 reward per railed tonne of HG from the Dry plant.

• $10 reward per railed tonne of LG from the Wet plant.

The sum across these values means that HG returns ($40) from the Dry plant and ($30) from the Wet plant, whereas LG returns ($30) from the Dry plant and ($40) from the Wet plant. As such, the optimiser prefers to sent HG to the Dry plant but can top up the Wet plant if required.

Cash Flows by Material

This example prioritises feeding HG first, then MG, then LG, to maximise the returned metal content.

• $100 reward per feed tonne of HG.

• $50 reward per feed tonne of MG.

• $20 reward per feed tonne of LG.

Cash Flow Values

Users are encouraged to pick values that express the relative importance of each transaction. For example, if high grade yields twice the revenue of low grade, give it twice the cash flow.

Cash Flows between Stockpiles

To enable movement between stockpiles:

1. Press Add Product Specification button and from its dropdown select "Stockpile Cash Flow".

2. Name it as "RehandleThreshold_setTo1000", for example.

3. Set the units to “mining_” volume or Tonnes, depending on the units you schedule the material in these stockpiles.

4. Select the Source and Destination stockpile.

5. In the Calendar, set the cash flow to 1001.

Blend Target

Item	Description	Example
Specify Min	Limits minimum ratio of the material fed from the Source to the Destination. Crusher feed will be zero if it cannot satisfy a Minimum blend ratio. Make sure there is material available before setting a minimum feed ratio.
Specify Max	Limits maximum ratio of the material fed from the Source to the Destination.
Minimum and Maximum are hard limits, “Actual” values cannot be outside of these boundaries. If Minimum limit cannot be satisfied, the optimiser returns zero. If Maximum limit is reached, no more material can be sent to the specified destination. Note that when setting ratios for multiple plant components, their “Actual” values must add up to 1.
Specify Target	Specifying target also introduces “Content Deviation Penalty” input row in the Calendar. The difference between the Actual and the Target blend is subject to this Penalty multiplier specified by the user. The Penalty is summed with the Cash Flows to determine the reward or cost of blending materials into each Destination. The higher the deviation penalty, the better the optimizer will try to meet the target, but it may not be achieved due to other cash flows and objectives.
Show Tram Lines	Displaying additional guidance lines for the optimisation rule in the Calendar. Used for visual purposes only to change the color of the “Actuals” field, ie if it goes out of range by more than 0.0001 it goes red, less than orange, otherwise it's black.	TBA
Numerator and Denominator	Blend ratios are calculated using a Numerator and Denominator, as such the setup requires both to be populated. Never configure the Denominator in a way that could return a zero. If the ratio returns a "divide by zero", then crusher feed will be zero.
Destinations	The Destination(s) to which the blend target is applied.
Quantity Field	The field to which the blend target is applied. As a general rule, the Numerator and Denominator should use the same units (either dry tonnes for the strict ratio, or wet tonnes for the weightometer ratio).
Sources	The Source(s) for Numerator and Denominator to which the blend target is applied.
View Database	Use the View Database button to open the Choose Records window, where you can graphically select and review the Sources.

Example: blend X up to 10%

This example targets a 10% LG blend into the crusher, but still feeds if there is no LG available.

• $100 reward per feed tonne of LG.

• 10% maximum ratio of LG into crusher feed.

Grade Targets

Grade targets allow the user to specify a strict grade range, and place penalty multipliers on deviation from the target. Different destinations may have different grade targets. 

Grade Fields

Grade specifications can be set to reference any field in the database.

Insitu Fields

Use these fields on stockpiles and crushers when targeting a head grade.

Process Streams Fields

Use these fields to target product grades on stockpiles. Since the software does not know what crusher the stockpile will feed into, the user is required to specify the processing stream of the quality fields.

Output Fields

Use these fields to target product grades through crushers. Since the software knows the process stream for each crusher, the “Output” fields act as a wildcard to automatically select the corresponding grade fields.

Grade Lower Limit

The final weighted average grade cannot be below this value.

• Individual feed blocks can be lower than the minimum.

• If multiple destinations are listed, individual destinations can be lower than the minimum.

Grade Upper Limit

The final weighted average grade cannot be above this value.

• Individual feed blocks can be higher than the maximum.

• If multiple destinations are listed, individual destinations can be higher than the maximum.

Grade Target

The difference between the actual grade and the target grade is subject to a penalty multiplier specified by the user.

Net grade penalty = (Content Deviation Penalty) * (actual grade - target grade) * 100 * (total tonnes)

If Crusher A and Crusher B have different grade targets, then a single block will incur a different penalty depending on the destination. This penalty is summed with the Cash Flows to determine the reward or cost of blending materials into each destination.

Content Deviation Penalties

The value of the content deviation penalty should be considered relative to other grades, and relative to the Cash Flow values.

• If the net grade penalty is greater than the crusher cash flow, then the crusher won't feed.

• If the Fe grade penalty is greater than the Al grade penalty, then the optimiser may blow out Alumina to keep Iron on spec. This is because the penalty of dirtying Al is lower than the penalty of dirtying Fe.

Notes

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