Calculated Blends

• Calculated Blends
• • Blend Configuration
  • • Sources
    • Specifications
    • Target Tonnes and Sensitivity
  • Blend Templates
  • Blend Calculation
  • Blend Results
  • Blend Assignment
  • Calculated Blending Module Limitations
  • Webinar

Note: MineMarket has two blending modules. See also Manual Blends.

The simplest form of calculated blending is to calculate an optimal blend on a one-off basis from a set of source stockpiles: Given a set of source stockpiles of known quantity and quality (for example, finished coal), calculate the best possible blend for a target blend specification (for example, a train), minimising the overall deviation from the target specification, taking several constraints into account.

For example, take the case of two analytes, where the sources of the destination blend are Stockpiles A, B and C. Stockpile A contains 1000 tonnes, 12% ash, 6500 CV. Stockpile B contains 2500 tonnes, 14% ash, 6100 CV. Stockpile C contains 1500 tonnes, 8% ash, 6800 CV. The blend target is 2000 tonnes, 9.5% ash, 7100 CV.

This is subject to:

• Analytes are not all equivalent in importance. CV may be more important than ash, so the algorithm must allow weighting factors to be assigned to each analyte. In this case, CV could be set to have a weighting of 3, and ash to have a weighting of 1.
• The blend must be practical in terms of reclaiming. A minimum reclaimable quantity for each source stockpile must be configurable. In this case, set a minimum of 20 tonnes for each source stockpile (that is, the calculated blend must not call for less than 20 tonnes from any stockpile, but it can call for zero tonnes from a stockpile).
• The user may want to force a certain amount of a material to be used from a specific stockpile. For the above case, specify that exactly 500 tonnes must be used from Stockpile A.
• Absolute limits must be enforceable. Even though the algorithm is being asked to calculate the blend that is as close as possible to the target (but does not necessarily exactly meet the target for every analyte), some analytes can have rejection limits that may not be violated. In the above case, allow CV to be no lower than 6950.
• Warning limits for analytes may be exceeded, but only if absolutely required. In the above case, allow CV to have a warning limit of 7050.
• The sum of material from Stockpiles A, B and C must equate to 100% of the blend, and no proportion may have a negative value.
• In some cases, it is desirable to be able to specify a factor for each stockpile that indicates its desirability in the blend. For example, if many blend combinations are feasible, the algorithm should pick the blend that uses the stock in order of preference, based on the factor. So, in the above example, Stockpile A and B could have a factor of 5, while Stockpile C has a factor of 1. The algorithm should attempt to use A and B in preference to C.

Note: The analytes blend as weighted-averages.

Blend Configuration

Sources

Several MineMarket object types can be specified as blend sources:

• Stockpiles—Calculated blend sources are most typically mine sources or weighted-average grade (WAG) stockpiles. The Calculated Blending module does not take into account the layers in first-in-first-out (FIFO), last-in-first-out (LIFO) stockpiles. Therefore, the use of FIFO or LIFO stockpiles as blend sources is not recommended, even though they can be selected. Do not use 3D stockpiles with the Calculated Blending module.

  For blends calculated without using a template, default blend source stockpiles are the stockpiles at locations for which there is a process flow to the blending location. You can add stockpiles at other locations, which is reasonable if those stockpiles are further back in the supply chain.

  When configuring a template, you might choose to add a stock location or stockpile category as a blend source. If you select a stock location, the stockpiles only display when you use the template to create a blend. This simplifies the blend template configuration for locations with many stockpiles, or if stockpiles are often opened or closed at that location. If you select a stockpile category, the stockpiles display in the blend template, allowing for more complex template configuration. Either way, when you create a blend using the template, you can refresh the list of available stockpiles at the location or in the category.

  Stockpiles can only be used as blend sources if the current state of the stockpile has analyte values.

• Products/brands—A product or brand can be added as a blend source to represent material that is expected to be in transit to the blending location. For example, consider 20,000 tonnes of Product A on multiple trains and 15,000 tonnes of Product B on multiple barges (all in transit to the blending location). Product A and Product B are added to the blend configuration as sources, and the tonnes are specified for each: Product A (20,000) and Product B (15,000). The quality values can also be updated (if required, because they default to the product target values) to simulate the total quality on these trains and barges. Alternatively, material in transit can be modelled using a transport route (see below), which gives more control over which despatches are included in the blend.
• Specification templates—A specification template can be added as a blend source to represent material that is expected to be available with that quality at the blending location.
• Process flows—A bulk material process flow can be added as a blend source. Stockpiles at the source location of the process flow are available as blend sources.
• Transport routes—A route can be added as a blend source. Adding a route adds relevant despatches when a blend is being calculated. Relevant despatches have at least one loading transaction before the blend date but do not have an unloading transaction. Each despatch can be included or excluded as required.

The blend sources in the Source Stockpiles table can be filtered. The sources that display after filtering are the only sources that can be included in the blend. That is, for any sources that are filtered out, Include is unchecked.

You can select a Contributor Group to display read-only contributor values for the blend sources.

For each source, you can:

• Select whether to Include the source as a possible source for the blend. MineMarket will not necessarily include every source for which Include is checked. If a source must be used, specify a quantity for Forced Usage.
• Update the Available quantity if required. For stockpiles and despatches, MineMarket displays the available quantity. For other source types, you can enter a quantity. All quantities in the calculated blending module are displayed in metric tonnes.
• Specify a Minimum Reclaim. A quantity entered for minimum reclaim is only used if MineMarket calculates that that source should be included in the blend. Specifying a minimum reclaim is useful to ensure that the suggested blend does not include a small quantity for one source that would be impractical to reclaim.
• Set a Desirability level.
• Specify a quantity for Forced Usage if required.
• Update analyte values if required. The values default to the best known values for the source, but these values can be overridden. The blend configuration includes options for analyte display that can be used in combination:
  • Only show the included analytes in the blend calculation specifications.
  • Select an analyte group to limit the display of analyte values.
  • Hide analytes without values.

Note: When blending for a stockpile, the current stockpile is always included as a source stockpile with a Desirability of 10 in the blend because its contents will be part of the blend result.

Specifications

The specifications dictate the target quality and acceptable quality range of the blended material. The specifications can be based on the specifications of a product, brand, stockpile, specification template or despatch order.

For each analyte in the specifications, you can:

• Select whether to Include the analyte in the blend calculation.
• Set a Weighting.

Target Tonnes and Sensitivity

Each blend or blend template has a target number of tonnes.

You can also selected whether the blend calculation should prioritise stockpile desirability or the target analyte quality. For example, it may be more important to use up certain material; or it may be more important to meet a contractually agreed quality of blended material.

Blend Templates

Blend templates are optional.

Blend templates save time when calculating similar blends. Blend templates store the blending details of the sources (most typically, stockpiles) to be included in a blend, and the desired specifications. You can assign priorities to analytes and stockpiles, include or exclude blend sources and specify minimum and forced usage reclaim quantities.

Blend templates are specific to the Calculated Blending module of MineMarket and are not used with manual blends.

You can create blend templates directly from the Solution Explorer under a blend category, or by saving a blend as a blend template.

A blend template must belong to a blend template category or sub-category. If you save a blend as a blend template, MineMarket stores the blend template in the Unassigned Blend Templates category. You can drag blend templates to another blend template category if required.

You can assign blend templates to a stock location, despatch location or stockyard. Assigned blend templates display in the Solution Explorer context menu for the location and its stockpiles; and in the Blending screen when creating a blend for the location or stockyard or one of its stockpiles.

Blend Calculation

You can calculate blends for the following objects: locations, stockpile categories and WAG stockpiles (via the Solution Explorer), trains (via the Train Explorer), service trips (via the Barge Explorer), and shipments (via the Shipment Explorer), and despatch orders on despatches (via a Train, Truck Despatch, Service Trip, Shipment or Lot Despatch).

You can specify a blend template, or create a blend from scratch. Even if you use a blend template, you can edit the sources and specifications, target tonnes and sensitivity.

Blend Results

If a blend is possible, the blend displays on the Results tab. Otherwise, an error message explains why the blend with the current criteria is not possible.

In the blend results, colour indicates the range in which the analyte value falls. Between the lower warning and upper warning, the colour of the row is the system-defined background colour. Between the minimum and lower warning, or upper warning and maximum, the colour of the row is orange. If the value of the analyte is on or outside the maximum or minimum, the colour of the row is red.

The Blend Results Script Editor can be used to enter a C# script to update the results of a calculated blend if required.

Blend Assignment

You can assign stockpile or despatch order blend results so that you can compare the analyte values of the blend with actual analyte values later. These planned analyte values display on the Current State tab of the stockpile or the Summary tab of the applicable despatch. Assigning a blend to a stockpile also updates the stockpile's Planned Quantity.

'Assembly blending' occurs when a blend is assigned before any loading transactions occur, and then interim blends are calculated that take account of the actual transactions. An interim blend uses the latest assigned blend as the Master Blend by default. This master blend functions like a template for the new blend, and a different assigned blend can be selected if required.

Calculated Blending Module Limitations

The Stockpile Results and Blend Results tables can be copied to the clipboard or printed. However, MineMarket cannot automatically create transactions from the suggested blend stockpiles. This is because source stockpiles may have been used for which there is no direct process flow between the locations. (However, in Manual Blends, MineMarket can create transactions and any required process flow.)

Only the latest assigned blend values can be viewed on the stockpile or despatch. However, you can view all blends via the Blending screen.

Analyte values from a blend assigned to a despatch order cannot be viewed on the Despatch Order; however, the analyte values can be viewed on the Summary tab of the applicable despatch.

Blends can be calculated for service trips and shipments without a despatch order (via the Barge Explorer or Shipment Explorer); however, these blends cannot be assigned. Nevertheless, the blend results can be copied to the clipboard or printed, and remain available via the Blending screen. Blends for trains without a despatch order can be calculated (via the Train Explorer) and assigned to a train rake.

Likewise, blends calculated for locations and stockpile groups (via the Solution Explorer) cannot be assigned.

Blends cannot be calculated for truck despatches; however, can be calculated for despatch orders on a truck despatch or on a lot despatch of trucks.

Webinar

Datamine held this webinar about using blending templates to create a reclaim plan.