Formatting the Block Model
Table of Contents
1 Block Model Specifications
1.1 Basic Requirements
MiningMath requires the following formatting specifications:
Regularized block model. This means all blocks must have the same size.
Non-rotated model. All blocks must be aligned to the default axis.
Air blocks must be removed prior to importation. This is the way MiningMath recognizes the topography.
Index Coordinates also referred to as IJK.
Header Names should not have special characters or exceed 13. Use this recomendation for folders and files also.
Data format should be a CSV file (Comma Separated Value), which might be compatible with most mining packages.
Configure Microsoft Windows number formatting to use dot as the decimal separator.
Use the metric system.
Set multiple the fields that will consider different economic values, material types, contaminant limits, and any other variable you wish to analyze or control.
1.3. Understanding Field Types
Field Types are the fields MiningMath can understand. Each column imported should be assigned to the proper field type in order to MiningMath treat each variable accordingly.
Mandatory Field Types and their meanings
Index X, Index Y, and Index Z refer to index columns for X, Y, and Z, respectively.
Average refers to any variable that could be controlled by means of minimums and maximums considering its average: grades, haulage distance and other variables.
Economic Value refers to the columns with the economic value, i.e. columns that represent the destinations available.
Note: it is possible to import multiple economic values at once, whether they will be used simultaneously (ex.: multiple processing streams) or separately (ex.: economic scenarios with different selling prices).
Optional Field Types and their meanings
Density refers to the block's density. This field is used to calculate the block's tonnage.
Slope refers to slopes varying block-by-block.
Note: this functionality gives the flexibility to define slopes by lithotype and sectors. Simply assign the slope to which each block should be subject.
Recovery refers to recoveries varying block-by-block.
Sum refers to any variable that could be controlled by means of minimums and maximums considering its sum.
Skip refers to any variable that should be ignored. This is an optional field.
Advantage: this field type might help improve the run time as fewer fields are loaded into the computer's memory.
Disadvantage: skipped columns will not be exported along with the optimization outputs. If you want to keep original information in the outcomes, assign it to SUM.
2 Formatting Steps
2.1 Mandatory Fields
Considering the specifications mentioned before, the formatted data set should have the following information for each block:
Indexes IX, IY, IZ (often referred to as IJK).
Grades (at least one element assigned as Average).
Economic values (at least 1 process and 1 waste).
The following video gives an introduction on how to setup your block model.
2.2 Index Coordinates
The indices of each block represent its position in the model, indicating in which column, line, and level (IX, IY, and IZ) it is.
The indices must be integer values, starting with any value (for Marvin model, it was adopted the indices 1,1,1 for the first block).
The model’s origin must be placed at the bottom portion, starting to count from the minimum coordinates at X, Y, and Z.
Figure 1 highlights the origin of the Marvin block model and the first block index coordinates (1,1,1).
Figure 1: Blocks Matrix.
However, if the block model contains geo-referenced information based on coordinates, they must be converted into indices before being imported to MiningMath.
To perform this conversion, check the following demonstration on how to convert coordinates into indices using data from Figure 2 and the equation from Figure 3.
Figure 2: Sample data to convert coordinates into indices.
Figure 3 exemplifies using the X-axis but the process is the same for Y and Z axes by just using the corresponding information.
Figure 3: Equation to convert coordinates into indexes.
Figure 4 shows the resulting coordinates for the sample data.
Figure 4: Resultant coordinates converted to indexes.
2.3 Tips & Tricks: Attention to software conventions
Each software uses its own conventions for data format, naming and numbering systems, etc. These differences should be observed to prevent conflicts when transiting data from multiple software, each one for one specificity.
What you must know:
MiningMath uses indexes (IJK) for which IZ starts upwards (Figure 5a).
Other mining software may use indexes with IZ starting downwards (Figure 5b). MineSight is an example that uses this notation.
There is no right or wrong convention, but there is a correct procedure for each software, as shown in Figure 5.
How to invert indexes
The formula to convert it is the following one.
new(IZ) = max(IZ) + 1 - current(IZ)
Figure 5a: On MiningMath, IZ must start to count upwards, i.e. the lowest IZ value is at the bottom of the model.
Figure 5b: On other mining packages, IZ starts to count downwards, i.e. the lowest IZ value is at the top of the model, which will not fit MiningMath needs.
Do you want more details on Index Coordinates?
The video below exemplifies the conversion process in case you have any doubts.
2.4 Air Blocks
MiningMath recognizes that all imported blocks of your model are underground. This means it is necessary to remove all the air blocks prior to importation. Unless your topography is totally flat, which is unlikely, the image below shows an example of your model should be displayed.
The non-removal of air blocks may lead to unsatisfactory results and long processing times since it would be considering blocks that do not exist in reality.
Figure 6: Example of how block models should look like with a rectangular base.
Do you want more details on Air Blocks?
The following video shows how to do remove air blocks using filters on MS Excel. These tips are also applicable to any mining software of your choice.