EXPMMW Process
To access this process:
-
Enter "EXPMMW" into the Command Line and press <ENTER>.
See this process in the Command Table.
Process Overview
This process expands a set of planar perimeters according to a user defined minimum mining width (MMW). This will allow perimeters which describe geological or grade boundaries to be expanded into a mineable entity.
The perimeters must be planar, but not necessarily in one of the orthogonal planes.
The process first calculates the plane of each perimeter, and transforms the coordinates into that plane; the perimeter is then tested against the MMW constraint and adjusted as necessary; finally the expanded perimeter is transformed back into its original plane. The test against MMW is done by first calculating the centre line of the perimeter.
A minimum perimeter is created based on this centre line with the MMW being measured perpendicular to the line. Each side of the minimum perimeter is then 0.5 x MMW from the centre line. The original perimeter is then tested against the minimum perimeter and is adjusted, if necessary, to ensure that no part of it lies within the minimum perimeter.
The expanded perimeter is then written to the output file. All perimeters will automatically be checked for crossovers and consecutive duplicate points Duplicate points will be removed. Malformed perimeters will be reported, but they will not be processed or included in the output file. Input perimeters may be either open or closed. Output perimeters will be closed. It is not possible to define an algorithm which will deal with every shape and size of perimeter. Therefore it has been implemented as a two pass process, controlled by parameter MODE.
User interaction is required between the passes to check and if necessary edit the strings. Pass 1 (MODE=1) takes as input the original perimeters from the PERIMIN file and creates the PERIMOUT file containing the original perimeters, the centre line strings and the expanded perimeters. The strings in this file can then be checked interactively in the graphics window.
If EXPMMW has not produced a satisfactory expanded perimeter then the centre line string should be edited appropriately. Two extra fields will be created in the PERIMOUT file:
PTYPE - the perimeter type field. This expects values:
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0 - the original perimeter
-
1 - centre line string
-
2 - expanded perimeter
PORIG - this field contains the PVALUE of the original perimeter.
If the PERIMIN file contains a field then these values will be carried through to the PERIMOUT file. The value of will be incremented by 1 for centre lines and by 2 for expanded perimeters. If the PERIMIN file does not contain a field, then a field will be created in the output file. The of each original perimeter will be assigned a value of 1, 2 for centre lines and 3 for the expanded perimeters. Editing the centre line strings in the graphics window will usually only involve small changes to the centre line strings near the intersection with the original perimeters.
Pass 2 through process EXPMMW takes as input a file containing both the original perimeters and the centre lines. Fields PTYPE and PORIG are required in the PERIMIN file. In practice it is probably best for the PERIMIN file to contain all perimeters even if the centre line did not require editing. In this way all the expanded perimeters are kept in the same file.
Input Files
|
Name |
Description |
I/O Status |
Required |
Type |
|
PERIMIN |
The input perimeter file. If MODE=1 then the fields required are XP,YP,ZP, PTN and PVALUE ie standard perimeter format. Any other fields in this file will not be copied to the output file. All valid perimeters in the file will be used. If MODE=2 or 3 then it must also contain PTYPE and PORIG fields. In addition the file must be sorted on the keyfields PORIG, PTYPE and PTN. |
Input |
Yes |
String |
Output Files
|
Name |
I/O Status |
Required |
Type |
Description |
|
PERIMOUT |
Output |
Yes |
String |
The output perimeter file containing the expanded perimeters. It may also contain a copy of the original perimeters and the centre line strings depending on the value of parameter MODE. The file will contain the standard perimter fields XP,YP,ZP,PTN and PVALUE plus ,PTYPE and PORIG. Malformed input perimeters will be reported but not processed. In place processing is not permitted ie PERIMIN and PERIMOUT must be different files. |
Parameters
|
Name |
Description |
Required |
Default |
Range |
Values |
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|
MMW |
The minimum mining width, measured perpendicular to the centre line of the perimeter. Any point on the expanded perimeter will be at least 0.5 x MMW from the centre line. |
Yes |
Undefined |
Undefined |
Undefined |
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|
PINC |
Numeric increment for PVALUEs for centre line string and adjusted perimeter as written to the PERIMOUT file. If the PVALUE of the input perimeter is P then its centre line string will have a PVALUE of P+PINC and the expanded perimeter will have a PVALUE of P+2xPINC. The default value is (0.1). |
No |
0.1 |
Undefined |
Undefined |
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|
MODE |
This parameter defines the contents of both the PERIMIN and PERIMOUT files. It has values:
|
No |
1 |
1,3 |
1,2,3 |
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|
NODIAG |
This parameter specifies whether the centre line of a square perimeter should be the diagonal or the length. It has values:
|
No |
1 |
1,2 |
1,2 |
