Block Models

• Block Models
  • Standard Block Model Types
    • Resource Model
    • Reserve Model
    • Long Term Model
    • Short Term Model
    • Grade Control Model
    • Block Model in Reconciliation

A block model is a 3D model representation of a mines mining area. As the name suggests, a block model consists of 3D blocks. Depending on the type of block model these are usually uniform cubes or multipoint polygons. Each block typically has a unique ID and attributes such as tonnes, volume, grade, material type, lithology, and spatial coordinates.

The model names are configured to match your mine and the following are representations of model types that are typically imported into Reconcilor.

Standard Block Model Types

Resource Model

Resource models are generally used to capture the in situ estimates of the tonnage (mass), grade (qualities) as well as other associated attributes for the known orebody. Typically, the Resource model has the coarsest resolution of data and covers a large area compared to other models.

Resource Models are normally owned by Geologists and used in the reporting of annual declarations.

Reserve Model

Reserve models are also estimates, typically based on the Resource model but updated with additional drilling, mining dilution, ore loss, metallurgical recovery, and mining scale. Reserve models generally include a period, although this is not normally specific to a date as such, rather Year 1 / Month 1, Year 1 / Month 2 etc. Reserve models often form the basis for generating Budgets, Forecasts and Mine Plans. The Reserve model must cover the area of mining.

The Reserve Models are often owned by the Engineering or Planning departments and used in reporting of annual declarations.

Long Term Model

Long Term Model is a term commonly, but not always synonymous with the Reserve Model. This term can also be used to represent the basis, or source for Long Term Plans. Confirmation of the definition is company / client specific.

Short Term Model

Short Term Model is usually synonymous with a Grade Control or Mining Model. These models represent updates to either the Resource or Reserve models generated after additional information is made available during the mining process.

Grade Control Model

A Grade Control Model is used to update previous estimates (generally the Resource Model) with information that is obtained during the process of mining. Such information can include additional sample data, mapping / geological domain definition and so on. It generally forms the basis for the short term mine plans and is often owned by the Geologists. Grade control models are synonymous with mining models in Reconcilor. Not every operation produces a Grade Control Model and so it is not a requirement for Reconcilor.

Block Model in Reconciliation

As Block Modelling is a process of estimating what is in the ground, models are used to communicate to current and prospective shareholders the value of the asset that is in the ground.

To give shareholders the confidence that their money is wisely invested, geologists will typically perform different forms of Block Model reconciliations to show the accuracy of their estimates against actuals produced. However, performing these reconciliations is not always indicative of what has happened in reality due to variables that occur in the mining process that are not available at the time of estimating the model (e.g. trucking errors where ore material is sent to the wrong destination).

Some common reconciliations include:

• Spatially comparing two models by a common location (e.g. Pit, Bench or Stope).
  • This typically shows the effect of new information such as additional drill holes within an area of interest.
  • This can be used to change a shift in economic factors, where the commodity price has changed whereby a certain grade cut-off is no longer profitable to process, and thus shifts from ore to waste.

Note: Spatially in this context does not indicate the ability to report in 3D. Rather, the ability to report within common areas defined by the Location Hierarchy set up in Reconcilor.

• Temporal comparison of two models using surveyed surfaces.
  • Used to show the above but with the additional aspect of time, to show last month’s results as opposed to all time.
• Temporal comparison of a model by surveyed surfaces against trucking information (i.e. Haulage) reported from the operation.
  • Used to measure the misclassification of ore and waste material or haulage errors where material has gone to the wrong destination.
• Temporal comparison of a model (typically the Mining Model) by surveyed surfaces against plant feed or plant product (for an equivalent period) using grade or metal units.
  • Can be used to show the accuracy of grade estimates to actuals.
  • These comparisons are highly contingent on mine and planning compliance to ensure the material predicted in the model was sent to the correct destination (plant) and not misclassified.