compbe

Process Help

COMPBE - composite drillhole samples over benches - COMPBE

Process Name	Menu Path	Link to Command Table
COMPBE	Sample Analysis ribbon \| Prepare Samples \| Composite \| Composite Over Benches	Click here

Introduction
Files, Fields and Parameters
Notes
Example
Errors

Introduction

Composites drillhole data over horizontal benches.

How to use

The input file must be in standard sample format (as output by process DESURV). The output file is in an identical format. Up to a maximum of 20 explicit numeric data fields may be composited. These do not have to be specified; they are identified by the process as those fields which are not the standard ones (BHID, X, Y, Z, LENGTH, A0, B0, C0, RADIUS, FROM, TO).

The compositing method is shown in Figure 1. The drillholes are split exactly on horizontal bench elevations, unless the hole ends within a boundary, or the composite becomes longer than a specified length (by default twice the bench height). In the latter case, composites are split into the units of the maximum permitted length. Composites less than a specified minimum length (by default half the bench height) are ignored.

A reference elevation is given by parameter @ELEV and a bench height by parameter @INTERVAL.

If there is a gap between samples of less than or equal to a specified distance (parameter @MINGAP) it will be ignored; that is, the missing part will be assigned the grades of the whole composite. Any gap greater than this, but less than or equal to the parameter @MAXGAP, will be replaced by a dummy sample with the default values specified in the file. A gap larger than @MAXGAP will be taken to terminate the composite.

If the total length of samples with non-absent grade values within a composite is greater than @MINCOMP, then the average grade of those samples is assigned to that grade field for the entire composite. If the total length of samples with non-absent grade values within a composite is less than @MINCOMP, then that grade field is assigned an absent data value for the entire composite. For example: FROM TO AU 31.00 31.39 15.2 31.39 32.00 absent If @MINCOMP=0.1, this is less than the assayed length of 0.39 and so the grade of 15.2 is assigned to the whole composite. If @MINCOMP= 0.5, this is greater than the assayed length of 0.39 and so the absent data grade of - is assigned to the whole composite.

The file must be in the order of BHID and FROM, i.e. sorted in drillhole order in increasing downhole distance. This is the order output from the DESURV and HOLES3D processes.

Figure 1: Compositing method used by COMPBE

Weighting by density

If a density field exists in the file then this may be used to for density weighted compositing. The density field is defined as the optional field *DENSITY. If any density value is absent data then the default density value will be used.

Weighting by core loss or recovery

To include the effects of core loss, the user may specify one of two optional fields *CORELOSS (core loss as a percentage) or *COREREC (core recovery as a percentage) to be used during compositing. The lost portion of the core will be taken into account and used in compositing. The actual treatment depends on the optional @LOSS parameter. If @LOSS<=0 (default) then the lost part of the core will be assumed to have exactly the same grades, properties etc. as the recovered part; in other words, the core loss is ignored.

If however @LOSS=1 then the lost core will be assumed to have default grades, density, properties etc. which will be averaged with the recovered core values. If @LOSS>=2 then the lost core will be treated as cavity (zero density and grades) so that the grade of the total sample is effectively reduced by the cavity.

Files, Fields and Parameter

Input Files

Name	Description	I/O Status	Required	Type
IN	Sample data file, sorted on BHID and FROM. Expects fields BHID, FROM, TO, LENGTH, X, Y, Z, A0, B0.	Input	Yes	Drillhole

Output Files

Name	I/O Status	Required	Type	Description
OUT	Output	Yes	Drillhole	Composite file.

Fields

Name	Description	Source	Required	Type	Default
BHID	Drillhole identifier.	IN	No	Any	BHID
FROM	Downhole distance to sample top.	IN	No	Numeric	FROM
TO	Downhole distance to sample bottom.	IN	No	Numeric	TO
DENSITY	If present, composites will be density-weighted	IN	No	Numeric	DENSITY
CORELOSS	If present, will be taken as percentage core loss, and treated according to the LOSS parameter.	IN	No	Numeric	CORELOSS
COREREC	If present, will be taken as percentage core recovery, (100-core loss) and treated according to the LOSS parameter.	IN	No	Numeric	COREREC
ZONE	Name of field for compositing within. (may be numeric or up to 4 character alpha). This field must exist in the IN and will be copied to the OUT file. If specified then new composites will be created each time the value of ZONE changes.	IN	No	Any	Undefined

Parameters

Name

Description

Required

Default

Range

Values

INTERVAL

Bench height.

Yes

Undefined

MINGAP

Gap length to be ignored. The default gap is calculated as 0.05 INTERVAL. This default value is applied if the parameter is not specified, or if the value is specified as <=0. A gap of exactly zero is not permitted. If you want the composite to be split at every gap, use a very small value for MAXGAP eg 0.0001.

0.05

Undefined

MAXGAP

Gap length for termination of composite (0).

Undefined

ELEV

Reference bench elevation (0).

Undefined

MINCOMP

Minimum composite length [0.5 INTERVAL].

Undefined

MAXCOMP

Maximum composite length [2.0 INTERVAL].

Undefined

LOSS

If core loss or core recovery field is present, controls how it is handled:

Option	Description
0	Treat loss as part of sample.
1	Treat loss as default values.
2	treat as cavity [zero density and grades]

0,2

0,1,2

>2 to display each composite and output file DD (0).

0,2

0,1,2

Notes

A progress message is displayed every 500 samples read.

Example

!COMPBE

&IN(BHOLES.D), &OUT(COMPS.4), @INTERVAL=4, @ELEV= 35

>>> 170 SAMPLES INPUT <<< >>> 67 COMPOSITES OUTPUT <<<

Error and Warning Messages

Message	Description	Solution
>>> ERR 122 <<< ( fileno) IN COMPBE	Missing essential fields in input sample file or there are more than 20 explicit numeric datafields for compositing. Fatal; the process is exited.

>>> ERR 124 <<< ( fileno) IN COMPBE	The composite length specified in @INTERVAL is negative or zero. Fatal; the process is exited.

>>> ERR 130 <<< ( 0) IN COMPBE	The maximum acceptable composite length specified in @MAXCOMP is less than the required composite length specified in @INTERVAL. Fatal; the process is exited.

>>> ERR 131 <<< ( 0) IN COMPBE	The maximum acceptable composite length specified in @MAXCOMP is less than the minimum acceptable composite length specified in @MINCOMP. Fatal; the process is exited.