Composite From End Of Hole
This is a highly specialised function that extracts layers by compositing samples from the bottom of the hole going upwards. Composites are determined by the application of a threshold and, optionally, a cutoff for each layer. Layers are extracted sequentially and are written along with weighted averages of assay fields to a text file suitable for loading into the database. A detailed report of the compositing results for each layer in each borehole are also written to a note file.
To run this function: Choose Database > Composite > From end of hole, or...
Compositing starts from the bottom of the hole and proceeds upwards until the weighted average grade for the nominated threshold or cutoff fields reach that cutoff or threshold specified for the first layer. The process is repeated from the top of this layer for each subsequent layer.
Define the table containing the controlling fields
Enter the name of the table containing the fields on which the thresholds and cutoffs will be defined.
Define the note file for detailed results
Enter the Location and ID number of the note file to which details of the compositing will be written.
Define the text file for later loading
Enter the Location and ID number of the text file to which extracted layers will be written. This file will be suitable for loading back into the database.
Complete the COMPOSITE SAMPLES FROM END OF HOLE form and choose Apply to proceed to the DEFINE THE COMPOSITING CRITERIA form or Cancel to return to the COMPOSITING DATA submenu.
Define the field to which an upper limit is to apply
Nominate the field to which a threshold value will apply. Composites will comprise samples having a weighted average value for this field less than the specified thresholds.
Define the field to which a lower limit is to apply
Nominate the field to which a cutoff value will apply. Composites will comprise samples having a weighted average value for this field greater than the specified cutoffs.
Define the geology code to use for overburden
Nominate a character string to encode any interval above the extracted layers.
Number of zones
Specify the number of zones or layers that are to be extracted.
Geo Code
Nominate a character string to encode each of the required layers.
Upper Limit
Specify a threshold value to be applied for each layer.
Lower Limit
Specify a cutoff value to be applied for each layer. If a value of -1 is specified then the cutoff field is ignored and composites are generated on the basis of the threshold only.
Complete the DEFINE THE COMPOSITING CRITERIA form and choose Apply to display the DEFINE QUERY CONSTRAINTS form.
Enter any required constraints and choose Apply to begin the compositing process. All holes that meet the selection criteria and have composites formed are listed in the message window.
Messages
Upon completion of processing the name of the output note and text files which are created will be displayed in the message window.
Result
The note file will comprise, for each borehole, some survey information regarding that hole and, for each layer, a list of samples in and above that layer along with the cumulative weighted average value of all numeric fields with the top of the layer highlighted. The text file will comprise records for each layer in each hole giving the hole id, depths to and from, the layer code and weighted average values for all numeric fields.