Dilution reduction
This function applies dilution and reduction to ore/waste contacts and to the tops and bottoms of intervals in a drill hole.
To run this function: Choose Database > Analysis > Dilution reduction, or...
Interval table
Enter the name of the database interval table to use.
Digging zones
Digging zones allow for the specification of different dilution and reduction thicknesses depending on where we are in the drill hole. The determination of digging zones follows different rules for different mining strategies.
The upper digging zone will always be the first band in the drill hole.
Select the mining method to use to determine digging zones:
- None, no digging zones
- Truck & Shovel
- Dragline
The lower digging zone will be the last layer in the drill hole.
The lower digging zone will comprise all layers that lie below a given depth.
The middle zone will be all other bands.
Layers are defined as contiguous intervals of ORE or WASTE which have been previously assigned by the Drillhole Ore/Waste Discrimination function.
Use volume factor?
It is possible to supply different widths for dilution and reduction for a given contact. If so, a volume adjustment must be made and this factor will be stored in the result string files.
Depth to lower zone
If `Dragline' is selected for Digging zones then the depth from the top of the drill hole to the lower digging zone must be entered.
Top dilution, Bottom dilution
Enter the top and bottom dilution thicknesses.
Top reduction, Bottom reduction
Enter the top and bottom reduction thicknesses.
Attributes to composite
For each attribute to composite you must select the Attribute (which may be either one of the fields in the database table or one of the D-fields of the input string file), and the D-field (D7 onwards being available to be written into) in the output result string file to which the composite grade must be written.
D-Field
Select the description field of the resultant string file to which the composited assays will be written.
Attribute
Select a numeric field from the specified table, or a D-field from the input string file to composite.
Cutoff
Enter the value which interval must exceed for that interval to be re-classed as ORE.
Result file
Enter the name (location) of the results file. This name will be used to form two output string files and one note file. For example, if the name is `output' the files will be output1.str, output2.str and output1.not respectively.
The formats of the output string files are described below.
Zone selection method
Select the method that you wish to use for defining the samples to be selected for this function:
- NO SELECTION, do not select by geology, and so all samples in a drill hole will be used.
- MULTIPLE ZONES, define the interval by entering one or more geology codes.
- ZONE FROM TO, define the interval by entering the code at the top of the interval and the code at the bottom of the interval.
Missing data method
Select the method that you wish to use for dealing with missing intervals or negative data:
- ASSIGN CONSTANT, the missing or negative samples will be assigned a user specified value.
- WEIGHTED AVERAGE, the missing or negative samples will be assigned a value based on the length weighted average of the sample directly above and the sample directly below. Missing samples at the top and bottom of the hole will be set to the first or last positive sample respectively.
- ARITHMETIC AVERAGE, the missing or negative samples will be assigned a value based on the average of the sample directly above and the sample directly below. Missing samples at the top and bottom of the hole will be set to the first or last positive sample respectively.
Constant value
Enter the value to assign to missing or negative samples, if the Missing data method is specified as `ASSIGN CONSTANT'.
Input string file
Location
Enter the input string file location. This string file must be an output string file from the Drillhole Data Ore / Waste Discrimination function.
File id
Enter the input string file id.
Change WASTE above cutoff to ORE?
Select `YES' or `NO'.
Change ORE below cutoff to WASTE?
Select `YES' or `NO'.
Complete the DRILLHOLE DILUTION AND REDUCTION form and choose Apply. The VERIFY CREATION OF A FILE form is displayed if the result filenames already exist.
If you chose 'MULTIPLE ZONES' or 'ZONE FROM TO' at the Zone selection method prompt, one of two forms is displayed to allow you to select geological zones to process.
If you chose `NO SELECTION' at the Zone selection method prompt, or have completed the zone selection forms, the DEFINE QUERY CONSTRAINTS form is displayed.
Complete the DEFINE QUERY CONSTRAINTS form and choose Apply to begin the reduction and dilution calculations.
Processing
This function applies geological constraints to drill hole data and applies dilution and reduction to ore/waste contacts and to the tops and bottoms of drill holes.
Result
Two string files and a note file will be created as a result of this function.
The first string file produced as a result of this function will have the following format:
- Each string in the file represents a single hole containing a single point at the collar coordinates of the hole.
Each point contains the following information about the hole:
Y, X, Z = coordinates of the point in space D1 Hole ID D2 Total overburden thickness (thickness of WASTE above uppermost ORE layer) D3 Sum of ore thickness D4 Weighted average ore grade D5 Sum of internal waste thickness (excluding any WASTE below lowermost ORE layer) D6 Weighted average internal waste grade D7 onwards represent the weighted averages of the fields specified in the Attributes to composite scrolling region.
The second string file produced as a result of this function will have the following format:
- Each string in the file represents a single hole.
- Each segment of a string represents a contiguous set of ore or waste layers.
- Each point of the segment, except the last point, represents the top of an ore or waste layer from the hole. The last point of each segment represents the bottom of the contiguous set of layers.
- The points representing the tops of ore or waste bands will contain the following information:
| Y, X, Z = coordinates of the point in space | |
| D1 | Hole ID |
| D2 | 'ORE' or 'WASTE' |
| D3 | Width of the band |
| D4 | Depth of the top of the band down the hole |
| D5 | Depth of the bottom of the band down the hole |
| D6 | Blank, or volume adjustment factor if the Use volume factor? field is YES. |
| D7 onwards represent the composited values of the fields specified in the Attributes to composite scrolling region. | |
A note file will also be created, with the same name as the output file, but with a `.not' extension. It will contain information on description fields holding input and output, and the constraints used.