Formatting the block model
Block Model Basic requirements
MiningMath requires the following formatting specifications:
Regularized block model: This means all blocks must be 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.
Coordinates or Indexes of each block in the 3 dimensions.
Header Names should not have special characters or have them exceed 13. Use this recommendation for folders and files also.
The 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 fields that will consider different economic values, material types, contaminant limits, and any other variable you wish to analyze or control.
Understanding Field Types
Field Types are the fields MiningMath can understand. Each column imported should be assigned to the proper field type so that the software treats each variable accordingly with its meaning.
Mandatory Field Types and their meanings
Coordinates X, Y, and Z refer to your geo-referenced information. The same applies to Index X, Index Y, and Index Z, which requires a column for each one of the 3D axes.
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, which represent the available destinations. It is possible to import multiple economic values at once, and they may be used simultaneously (ex.: multiple processing streams) or calculated in the internal calculator mentioned on the next page.
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, which gives the flexibility to define slopes by lithotype and sectors.
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.
Other refers to information that you with to have in the exported outputs.
Skip refers to any variable that should be ignored. This field type might help improving the runtime since these variables will not be considered and exported along with the optimization outputs.
Field names shortcut
Shortcuts can be used for auutomatic recognition in the importation process. These are listed in the table below.
Considering the specifications mentioned before, the formatted data set should have the following information for each block:
Coordinates or Indexes.
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.
Video 1: Block Model setup.
Attention to software conversions
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 a block model origin at the corner of the first block and the coordinates on its centroid.
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 coordinates (X,Y,Z) for which Z, which represents the elevation, starts upwards (Figure 3a).
Other mining software may use indexes with IZ starting downwards (Figure 3b). MineSight is an example that uses this notation.
There is no right or wrong convention, but there is a correct procedure for each software.
To invert coordinates use the following formula to convert:
\(new(Z) = max(Z) + 1 – current(Z)\)
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.
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.
Video 1: Removing air blocks using filters on MS Excel.