CHANNL3D Process

To access this process:

• Sample Analysis ribbon >> Desurvey >> Channels.
• View the Find Command screen, select CHANNL3D and click Run.
• Enter "CHANNL3D" into the Command Line and press <ENTER>.

See this process in the Command Table.

Process Overview

Note: This is a superprocess and running it may have an effect on other Datamine files in the project.

CHANNL3D converts a set of Channel Sample data and Channel Survey data into a 'desurveyed' Static Drillholes file in which each sample is identified by its location (X,Y,Z coordinates) and direction (azimuth and dip) in space. This is the same format as created by the HOLES3D process for drillhole data.

The input data consists of one survey file and one or more sample files.  If two or more Channel Sample files are specified (maximum 6) then they are merged so that all divisions of all sets of samples are maintained. A typical use of merging is to add an assay file to a lithology file, where the lithology intervals do not match the assay sample boundaries. Another example is to add absent data samples into channels by making the second file a single record per channel defining the total channel length.

The output from the CHANNL3D process is in the standard Drillhole format which is used extensively elsewhere in Studio. For example, the channels can be viewed interactively, composited along the channel, and used to interpolate grades into a block model.

Using Channel Survey Data

The Channel Survey data file is compulsory and must contain at least two survey points for each channel. If survey data is not included for a channel or there is insufficient data then an error will be reported.

Survey data consists of a channel identifier (BHID) and the coordinates (XPT, YPT, ZPT) of the survey point. The first survey point for each channel must be at the start of the channel. The positions at which the survey readings are recorded does not have to correspond to sample positions.

The survey data for each channel must be sorted on distance along the channel from the start of the channel.  However it is not necessary to include this distance as a field in the survey data file.

The process works by first converting the survey file to sample format by the addition of FROM and TO fields, thus creating a set of pseudo samples corresponding to the intervals between successive survey points.  This is then combined with the sample file(s) using the hole merge (HOLMER) process so that the samples are split at all sample endpoints.  The coordinates of the centre of each sample are then calculated by linear interpolation between the survey points on either side of the sample.  The azimuth (A0) and dip (B0) fields are also calculated from the survey data.

If the sample data extends beyond the survey data then the process will optionally extrapolate the survey data using the azimuth and dip of the last survey sample of the channel.  This is controlled by parameter EXTEND; if set to 1 then the output channel file will be extended to include all sample data; if set to 0 then the output channel file will terminate at the final survey point.

The process will optionally calculate the XYZ coordinates of the start and end of each sample. This is controlled by parameter ENDPOINT, which if set to 1 will create the six extra fields.

As well as creating the desurveyed channel file, OUT, the process will optionally create two other files, CHANSMRY and ERRORS, which assist in validating the input data.  These files are described below.

Optional Output File - CHANSMRY

The CHANSMRY file contains a single record summary of the input data for each channel.  The fields include:

• BHID - channel identifier
• SURVPTS - number of survey points for each channel
• SAMPLEi - number of sample records in SAMPLEi input file(s) for each channel
• SAMPLENG - maximum length of sampling over all ( 1 – 6) input sample files
• SURVLENG - cumulative length over all survey points
• DIFFLENG - difference in length between SAMPLENG and SURVLENG
• GAP_i - length of missing samples (FROM – previous TO) in input sample file i, i=1,6
• MAX_TO_i - maximum TO value in input sample file i, i=1,6
• SURVFILE - name of input survey file
• SMPiFILE - name of input sample file i, i=1,6

Although this file is optional it is recommended that it is created and checked.  In particular if the SURVPTS value is less than 2 then the channel will not be included in the OUT file.  Also if any of the GAP_i values are non zero then this indicates that samples are missing from sample file SAMPLEi which may indicate that the data needs to be checked.

Optional Output File – ERRORS

The ERRORS file reports inconsistent FROM / TO values in the samples files. The fields include:

• SAMPFILE - sample file number (1 – 6)
• BHID - channel identifier
• FROM - FROM value of record with inconsistent FROM / TO values
• TO - TO value of record with inconsistent FROM / TO values
• ERROR - error number:
• 1:  FROM > TO
• 2:  TO > next(FROM)  or  FROM < previous(TO)

If an error is identified then the OUT file will not be created.

Input Files

Name	Description	I/O Status	Required	Type
SURVPTS	Survey data point file containing channel identifier and 3D coordinates. Expects fields BHID, XPT, YPT, ZPT. The points must be sorted by location along the channel.	Input	Yes	Point Data
SAMPLE1	First sample data file. This file is compulsory and must include fields BHID, FROM, and TO. It will probably also include at least one sample attribute field, such as grade or lithology.	Input	Yes	Downhole Sample
SAMPLE2-6	Five optional sample data files containing BHID, FROM and TO, and probably at least one sample attribute field.	Input	No	Downhole Sample

Output Files

Name	I/O Status	Required	Type	Description
OUT	Output desurveyed sample data file. This will include fields BHID, FROM, TO, LENGTH, X, Y, Z, A0, B0, and all other fields which were included in the sample file(s). The X, Y and Z fields are the coordinates of the centre of each sample. The A0 and B0 fields are the azimuth and dip of the sample, respectively.	Output	Yes	Drillhole
CHANSMRY	Optional output file containing a summary record for each channel in the input files. Although the file is optional it is recommended that it is created as it can be useful for validating the data, and showing what data is missing from which channels.	Output	No	Table
ERRORS	Optional output file containing a list of samples which do not pass the validation tests. These validation tests identify errors in the FROM / TO values.  These errors will cause the process to fail so it is recommended that you create and review the ERRORS file.	Output	No	Table

Fields

Name	Description	Source	Required	Type	Default
BHID	Channel identifier	SURVPTS SAMPLE1	No	Any	BHID
XPT	X coordinate of survey point	SURVPTS	No	Numeric	XPT
YPT	Ycoordinate of survey point	SURVPTS	No	Numeric	YPT
ZPT	Z coordinate of survey point	SURVPTS	No	Numeric	ZPT
FROM	Along channel distance to sample start.	SAMPLE1	No	Numeric	FROM
TO	Along channel distance to sample end	SAMPLE1	No	Numeric	TO

Parameters

Name	Description	Required	Default	Range	Values
EXTEND	Option to extend channel beyond last survey point: 0 - Terminate channel at the last survey point. 1 - Extend channel to maximum TO value in the input samples files.	No	1	1, 3	1,2,3
ENDPOINT	Option to include the X, Y, Z coordinates of the start and end of each sample in the desurveyed output file. 0 - Start and end coordinates are not included in OUT file. 1 - Fields XSTART, YSTART, ZSTART, XEND, YEND and ZEND are created in the OUT file.	No	1	1,4	1,2,3,4

Example

!CHANNL3D  &SURVPTS(survey_points),  &SAMPLE1(ASSAYS),  &SAMPLE2(LITHO),

&OUT(CHANNEL_OUT),  &CHANSMRY(CHANNEL_SUMMARY),

&ERRORS(CHANNEL_ERRORS),  @ENDPOINT=1,  @EXTEND=1

Output window

CHANNL3D - Create drillhole representation of channel samples

  

... Input validation

... Checking sample file(s).

 ... No TO/FROM overlaps have been identified in sample files

  

 ... Calculating sample segment locations

 ... Merging samples from file ASSAYS

 ... Merging samples from file LITHO

  

 ... Creating summary file CHANNEL_SUMMARY

  

 WARNING:

 ... Some channels have no data for one or more input files.

 ... 3 channels have 0 or 1 survey points

 ... 2 channels have 0 samples

 ... Check file CHANNEL_SUMMARY for details

  

 ... Calculating sample end points

  

 Output Files:

 ... Results file CHANNEL_OUT contains 2874 records

 ... Errors file CHANNEL_ERRORS contains 0 records

 ... Channels summary file CHANNEL_SUMMARY contains 55 records

  

 CHANNL3D process complete