TS Product Specifications

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

1. In the first instance, each Agent selects a mining sequence determined by the dependencies, incentives, and constraints. No destinations are assigned.

2. In the second instance, an optimisation is run to determine the best destination for each ore parcel, using the Product Specifications as inputs.

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.

Main components and functions of this step are described below.

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Product Specifications step in a sample iron ore project

Cash Flows

Cash flows allow the user to specify an incremental reward or penalty for each (tonne/cube/ounce) of material sent to a destination. If two rules satisfy the same condition, then the cash flow is the sum of values in each rule.

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Set the source, material, destination, and unit on which to apply the cash flow

Cash Flows by Plant

This example 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

Cash flow values are strictly relative. Setting all fields to "10" is the same as setting all fields to "10000".

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

Movement between stockpiles incurs a default negative cash flow of (-1000) per bank cubic meter. This prevents the optimiser from going into circular rehandle loops.

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".

3. Set the units to "mining_volume".

4. Select the source and destination stockpile.

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

Blend Target

Blend targets allow the user to specify a maximum or minimum ratio of some material into a crusher or stockpile.

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.

Recommended Usage

Take note of these behaviours when using blend ratios:

• 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).

• 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.

• 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. 

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.