Composite Strata by Elevation
The purpose of compositing strata is to create regularized
samples and control bias for geostatistical modeling. For
example, one drilling campaign may have sampled strata on a 10'
interval, while another drilling campaign sampled on a 3' interval.
Using a mix of the two in modeling would lead to distinct zones of
higher and lower grade variability purely due to the measurement
length. Compositing the 3’ to 10’ would remove this
measurement bias.
It is important to note that this command will create new
drillhole entities rather than modifying the original drillholes.
This allows you to run other commands with either the original
drillholes or the composited drillholes to compare results.
When the command is first executed, you will be prompted to select
the drillholes to modify. The below dialog will then appear.
Drillhole Prefix/Suffix: These settings will apply a
prefix/suffix to the names of the composited drillholes.
Drillhole Type: This setting controls the Drillhole Type of
the composited drillholes. It is important to note that this option
will not allow you to select a Drillhole Type in use by the
selected drillholes - you must select a new drillhole type.
Drillhole Types may be modified by clicking the ellipsis button.
More information regarding Drillhole Types is found in the Drillhole Lookup
Database documentation.
Include Original Parent Sample Summary: When enabled, the
composited strata will contain additional strata attributes
indicating the strata attribute values from the contributing
strata.
Density Attribute: This option sets the density attribute
used for attribute weighting. This option is only required when
samples are attributes are weighted by Sample Weight (as opposed to
Sample Length)
Strata or Bed Naming Method: This option determines the
resulting strata/bed name when composites cross strata/bed
boundaries.
The Use Dominant option will retain the name of the
longest/heaviest sample contributing to the composite. For example
if a 10' composite is created from 7' of Strata A and 3' of Strata
B, the resulting composite strata name will be A.
The Concatenate option will concatenate the strata names
contributing to composite. For example, if a 10' composite is
created from 3' of Strata A, 3' of Strata B, and 4' of Strata C,
the resulting composite strata name will be ABC.
The Label Mixed option will not retain any of the original strata
names when more than one strata contributes to the composite, but
will instead label the resulting strata according to the name
entered for the Mixed Strata or Bed Label.
It is important to note that the Strata Names and Bed Names are
considered separately. If a composite is created from 3 samples of
Strata A with varying Bed Names, only the Bed Name will be subject
to change. Alternatively, if a composite is created from 3 samples
with 3 different Strata names but the same Bed Name, only the
Strata Name will be subject to change.
It is also important to note that the Set Bed To Bench Names
option will override any naming convention applied to the Bed
Names.
Key Status of Mixed Composite: This option controls the key
status of the resulting composite strata.
The Use Dominant option will retain the key status of the
longest/heaviest strata contributing to the composite.
The Key if Mixed Status will set all Mixed composites as key.
The Non-Key if Mixed Status will set all Mixed composites as
non-key.
Use Drillhole Min/Max Elevation: When enabled, this option
will automatically set the Max Elevation and Min
Elevation values according to the max/min values detected from
the selected option . When disabled, you will be able to set the
Max Elevation and Min Elevation values manually.
Fixed Elevation Calculation Mode: This option controls how
the Bottom Elevations will be automatically calculated. The Use
Vertical Divisions option will allow you to specify the
Number of Vertical Divisions to set between the Max
Elevation and Min Elevation. The Use Fixed Intervals
will allow you to enter the Fixed Elevation Intervals value
to set the Bottom Elevations for each Interval. To apply each
option, you may click the calculator icon to the right of the
spreadsheet.
Set Bed to Bench Names: This option will overwrite all new
bed names according to the Bench Names column of the
spreadsheet. When intervals are automatically calculated by
clicking the calculator icon, the bench names will be generated in
increasing order from top to bottom. You may specify a Bench
Prefix if desired.
The + and X icons next to the spreadsheet allow you to add or
remove rows. This is useful if you need to add a Bottom Elevation
that is not automatically calculated for you. It is important to
note that Bottom Elevations must be listed in decreasing order from
Top to Bottom. If this convention is not met, the out-of-order
cells will be highlighted with a red fill.
Numeric Attributes: This spreadsheet will list all numeric
strata attributes found in the selected drillholes. Strata
attributes may be averaged by the Weighting column (Sample
Length or Sample Weight). If the strata attributes contain a
specific value for null values, this value may be specified in the
Null Value column when the Has Null Value column is
set to Yes.
Text Attributes: This spreadsheet will list all text strata
attributes found in the selected drillholes. If the Naming
Method is set to Dominant, only the value of the
longest/heaviest contributing strata will be retained in the
composite, based on the option selected in the Weighting
column. If the Naming Method is set to Concatenate, the
resulting text value will be a concatenation of the contributing
text values. If the Naming Method is set to Label Mixed, the
resulting text value will be set according to the Mixed
Label column.
An example before and after compositing on 10' intervals from
elevation 1000' to elevation 950' is shown below. Note that the
strata names have been concatenated while the bed names have been
set according to the bench name.
Pulldown Menu Location: Drillhole > Strata/Bed
Utilities
Keyboard Command: compbench