compbr

Process Help

COMPBR - composite drillholes over benches with selective mining recovery

Process Name	Menu Path	Link to Command Table
COMPBR		Click here

Introduction
Files, Fields and Parameters
Example
Errors

Introduction

Composites drillhole data over horizontal benches, with additional computation of a recovered grade and recovered fraction for a specified field at a given cut-off.

How to use

The COMPBR process is a modification of the COMPBE process, and composites in an identical way. The difference comes in the recovered grade and fraction calculations. For the specified field *VALUE, the weighted FRACTION of each composite above the given parameter @CUTOFF is computed, together with the mean grade REC.VAL of this fraction. These values relate to those that could be achieved with selective mining within benches at the specified cut-off.

Further details of the compositing process are given in the COMPBE description.

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 process.

Weighting by density

If a density field exists in the file then this may be used too 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 Parameters

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. Will include implicit field CUTOFF and explicit fields REC.VAL and FRACTION for recovered values.

Fields

Name	Description	Source	Required	Type	Default
VALUE	Field for recovered grade computations.	IN	Yes	Numeric	Undefined
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

CUTOFF

Cutoff to be applied to VALUE.

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.

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

!COMPBR

&IN(BHOLES.D), &OUT(COMPSR.4), @INTERVAL=4, @ELEV=35,
@CUTOFF=0.5, *VALUE(CU)

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

Error and Warning Messages

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

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

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