Overview
The Washability module provides mechanisms for manipulating gravity-separation analysis data. The ultimate purpose of this system is to allow the modelling of wash tables for mining blocks from which product estimation calculations can be made.
The system converts user data into a Maptek standard washability Isis database. This process allows for multiple lithologies and, if required, missing/unlogged defaults to be combined as horizons in the standardised form. The standardised data is then used to create washability models, if required, with further combining of horizons for working-section analysis and interrogation.
The washability model information may be used to populate Harp/Block models to allow for Advanced Reserves reporting and establish properly weighted average wash tables for arbitrary mining blocks. The system also allows for dynamic interrogation of the wash models using arbitrary polygonal outlines to produce the correctly averaged wash tables. The composite wash tables can then be used for product estimation computations:
- Density required to achieve required product
- Product quality obtained by given density gradient
- Statistical reliability of gravity-separation at relevant density
- Products obtained as 1°, 2°, 3°, and so on extraction
- Inclusion of fines data with the gravity-separation
Wash tables can be analysed by this module, the original wash curve system, or various third-party analysis packages and may be used as input data (via Harp) for scheduling in Maptek Evolution software.
The system utilises the ISO 7936 (AS 4156.1) standards for computation.
Workflow
Here is a basic workflow for the Washability system.
1. Set up source database connections for the supplied washability data
In most cases, this step needs to be performed only once (per source database). It is also likely that there will only be one database per project. However, there can be more if required. It is therefore possible to make more than one setup for the same database, for example, one may ignore ply names while another uses them. Each connection set up is stored in its own specification file.
2. Set up any required default value wash tables that may be required by the next step
Set up as many different default wash tables as required. Each table must be given a unique name. They can be named to match horizon names or just the generic names.
Note: Â It is necessary to set up default value tables only as and when required. They are not a prerequisite to use the system.
The default tables are stored in one specification file per project; however, they can be copied between projects if required and compatible.
3. Set up specifications required for generating standardised wash tables
Most likely, only one standard for wash tables is required. However, if more than one is needed (eg. different analyses for different facies within a coal deposit), any number of specifications can be defined. However, each specification must generate its own standard database. Each specification set up is stored in its own file.
4. Run standardisation to produce required standard database of wash tables
This step, running one specification file to produce one standardised database of wash tables, may be run once or multiple times. When the source data is updated and/or added to as more analysis information becomes available as a mine progresses, it becomes necessary to run it again to regenerate the standard database(s) in order to produce up-to-date models.
5. Generate wash models from the standard database of wash tables
This step is likely to be run multiple times on the same data for different scenarios to generate different models. The settings required for modelling are stored in their own specification files.
6. Insert values from the wash table model stacks into a Harp/Block model
Taking the models produced from step 5, insert the values for each attribute modelled into a pre-existing structural Harp (or other Block) model. This will update a Harp model with the required values.
7. Create Advanced Reserves reports from the Harp/Block model
Advanced Reserves reports can now be made for reserving the required mining blocks using the modelled wash table values. Values associated with the wash analysis must be weighted using the new option which allows grades to be calculated taking yield into account—the variable values for each density fraction being weighted by the yield for that fraction.
8. Compile the wash table from each mine block report
The wash table values created by the reserves report can then be used to create the averaged interpolated wash table for each mine block. The wash table can be plugged into a graph for simple queries (yield per density, quality per density, density required to achieve quality) or can be used for more sophisticated analysis in Evolution (or the simpler third-party wash table spreadsheet analyser offered by Maptek).
