MineMap IMS 2.0
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Produced by W.S. Mart and G. Markey
For MineMap Pty Ltd
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Copyright © 2014 by William Seldon Mart and Geoff Markey. All rights reserved.
.
Page 1
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Table of Contents
INTRODUCTION.................................................................................................................... 4
COMPOSITING TYPES ........................................................................................................ 5
Type 1: Composite by Model Stratigraphies ...................................................................... 7
Type 2: Composite by Stratigraphy Name .......................................................................... 8
Type 3: Composite by Lithology ............................................................................................. 9
Type 4: Composite Waste, then Composite Everything up to a Cut off Band ....... 10
Type 5: Composite Waste, then Flag Everything up to a cut off Band ..................... 11
Type 6: Composite Contiguous Waste and Ore Bands .................................................. 12
Type 7: Stratify Using Composite Ranges ......................................................................... 13
Type 8: Stratify, then Apply Economic Rationale ........................................................... 14
Type 9: Stratify and Maximise Thickness ......................................................................... 15
Type 10: Create Fixed Length Samples .............................................................................. 16
Type 11: Write Samples Inside a Wireframe ................................................................... 17
INPUT AND OUTPUT .......................................................................................................... 18
Input Model File ......................................................................................................................... 19
Input Drillhole File ................................................................................................................... 20
Input Wireframe File ............................................................................................................... 21
Output Drillhole File ................................................................................................................ 22
Output Report Files .................................................................................................................. 23
Input Parameters ...................................................................................................................... 24
OPERATION OF COMPOSITE DRILL DATA ............................................................... 38
Page 2
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Composite Drillholes Using a Model ................................................................................... 38
Composited Grade of an Assay.............................................................................................. 40
Composite Based On Drillhole Stratigraphy .................................................................... 41
Obtaining An Optimum Depth .............................................................................................. 42
Optimum Depth Incorporating Surface Waste ............................................................... 43
Using Stratification Criteria................................................................................................... 44
The Start Criterion .................................................................................................................... 46
The Average Grade Criterion ................................................................................................ 47
The Break-out Criterion ......................................................................................................... 48
The Economic Criterion .......................................................................................................... 49
The Maximise Thickness Criterion ..................................................................................... 50
Fixed Length Samples .............................................................................................................. 51
Samples Inside a Wireframe ................................................................................................. 52
Page 3
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
INTRODUCTION
A collection of specialised compositing options is available via the MineMap IMS menu item
<Drillholes><Composite Data...> (Figure 1) and requires regular samples that have no stratigraphic
correlation. These options are:
(1)
Composites samples according to a constructed laminar model. E.g. a model may be
constructed using the menu item <Model><Laminar Model Operations><Modify Surface
Files...> to represent a dredge path, and the drillhole data is composited according to
laminations that make up levels within that dredge path.
(2)
Finds a maximum floor depth on the drillhole, where the floor sample is higher than a cut-off
and the average assay value from collar to floor is also higher than an average cut-off. This
method also has an option to include a top "waste" band of user-defined minimum thickness
and composited cut-off grade.
(3)
Starts from the deepest sample and works its way up the hole, until a value passes a cut-off
criterion. It then checks that the minimum thickness criterion will sustain an acceptable
average grade, and continues to composite samples upwards until either a break-out grade is
obtained or the average grade ceases to remain acceptable. The composited samples are
identified by a stratigraphic name and the next group of samples up the hole are checked
against the next stratification criterion, etc. This method includes the option of incorporating
internal "waste" bands between the stratified composite intercepts.
(4)
Utilises the same compositing parameters outlined in (3) but adds economic criteria. Ore
processing and waste removal costs can be specified to further determine the optimum
composite intercepts.
(5)
Maximises the thickness of a composite for a desired grade. The grade that you want is
nominated then the algorithm composites all adjacent samples that fall under this value. The
composite interpolates the upper and lower boundaries of a given sample.
<Drillholes><Composite Data...> (Figure 1) complements the compositing options available via the
menu item <Drillholes><Examine Composite Grades>.
Page 4
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
COMPOSITING TYPES
Select <Drillholes><Composite Data...> (Figure 1).
Figure 1: Locating MineMap IMS option
Page 5
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
You will then be prompted to select one of eleven options available in the Composite Types dialog
box (Figure 2).
Figure 2: Compositing types
Page 6
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Type 1: Composite by Model Stratigraphies
This option provides a composite for each stratigraphy (bench or seam) of the model and is the only
option that utilises a model for structural delineation. It will write out zero thickness seams (valid for
coal and other similar laminar models).
If multiple qualities exist in the input drillhole file then the composite assays can be weighted by
another quality via the Weight the Composite Assays dialog box.
Page 7
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Type 2: Composite by Stratigraphy Name
This option simply combines adjacent samples, if their strat names match.
No composite will be created across an unsampled interval.
Page 8
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Type 3: Composite by Lithology
This option composites samples based on the intervals of a selected lithology comment. Once you
have selected Composite by Lithology in the Compositing Types dialog box, the Lithology for
Compositing dialog box becomes available for you to select which lithology comment (1-5) to use for
compositing.
Each drillhole in the input file is processed by compositing samples according to the intervals of the
selected lithology. Where adjacent lithology intervals have matching codes, a single composite is
produced. The lithology code is used as the stratigraphy name for the resulting sample.
Page 9
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Type 4: Composite Waste, then Composite Everything up to a Cut off Band
This option provides an optimum hole based on the cut-off criteria. It outputs a composite with a
nominal name of "C1" to identify the stratigraphy. The “waste” band above the composited ore is
optional and the compositing criteria are defined using the input parameters for Assay Compositing
Parameters dialog box
You can also choose to use an assay to weight other assays in the drillhole file by selecting the assay
used for weighting in the Weight the Composite Assays dialog box.
Page 10
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Type 5: Composite Waste, then Flag Everything up to a cut off Band
This option uses the same criteria as option 4 and is used hand-in-hand with the above type. The
difference is that this option outputs the data as original un-composited samples, flagged with a
stratigraphic name (i.e. those samples that pass the cut-off and average grade criteria). It is useful for
generating statistics on the nature of the grade distribution within the optimum composite.
Page 11
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Type 6: Composite Contiguous Waste and Ore Bands
This option provides a hole with waste bands and ore bands under the user input waste band to ore
band transition criteria. The compositing criteria are defined using the input parameters for Assay
Compositing Parameters dialog box
You can also choose to use an assay to weight other assays in the drillhole file by selecting the assay
used for weighting in the Weight the Composite Assays dialog box.
Page 12
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Type 7: Stratify Using Composite Ranges
This option uses a series of tests to isolate one or more significant intervals or stratigraphies within a
drillhole. The criteria are defined using the options provide in the Range Criteria dialog box.
There are two criteria available under this composite method: The use of Multiple range criteria and
Apply one criterion repeatedly which uses single range criteria.
You can also choose to use an assay to weight other assays in the drillhole file by selecting assay used
for weighting in the Weight the Composite Assays dialog box.
Page 13
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Type 8: Stratify, then Apply Economic Rationale
This option uses a series of tests to isolate a number of stratigraphies within a drillhole. The criteria
are defined using the Range Criteria dialog box.
You can also choose to use an assay to weight other assays in the drillhole file by selecting an assay
used for weighting in the Weight the Composite Assays dialog box.
The drillhole file has economic criterion applied to it as costs of waste and ore removal based on the
parameters entered in Economic Parameters dialog box.
NOTE: This option requires that relative density is incorporated into the drillhole file.
Page 14
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Type 9: Stratify and Maximise Thickness
This option maximises the thickness of a composite for a desired grade. The grade of most composites
will be equal to the desired grade. A weighting assay (i.e. sample recovery factors, specific gravity)
can be applied to the composite, if desired, via the Weight the Composite Assays dialog box.
The Stratify and Maximise Thickness dialog box is used to set further compositing criteria.
Page 15
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Type 10: Create Fixed Length Samples
This method of compositing weights the original sample grades by length, converting them to a
nominated sample length. The compositing works down the hole from the first sample. However, if
the drillhole has been sampled irregularly (i.e. there are unsampled intervals) then the compositing
starts again from the next sample.
Weighting the assays is possible by using a nominated assay.
Page 16
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Type 11: Write Samples Inside a Wireframe
This option is a filter rather than a compositing method and simply determines which samples are
inside a wireframe and writes these samples to the output file. The wireframe is selected via the
Wireframe dialog box and writes these samples to the output file. No compositing is performed.
If compositing is required, follow this option with option 1.
NOTE: this option works best with shorter samples, since it only checks the midpoint of a sample. If
the input file has already been composited, the result may be incorrect.
Page 17
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
INPUT AND OUTPUT
An MineMap IMS drillhole (DHL) file is required for all the available options. The output is always
another MineMap IMS drillhole file (DHL). Report files are also generated if required.
Page 18
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Input Model File
Compositing types 1 (Composite by model stratigraphies) and 8 (Stratify, then apply economic
rationale) require a model which should ideally be loaded before selecting the
<Drillholes><Composite Data...> menu item. If a model is not loaded then the Model dialog box
(Figure 3) will become available to select an appropriate file.
Figure 3: Model input dialog box
Page 19
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Input Drillhole File
For all the compositing types, an MineMap IMS drillhole file should ideally be loaded before selecting
the <Drillholes><Composite Data...> menu item. If a drillhole file is not loaded then the Drillholes
dialog box (Figure 4) becomes available to select an appropriate file.
Figure 4: Drillhole file input dialog box
Page 20
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Input Wireframe File
Type 11 (Write samples inside a wireframe) requires a wireframe. The MineMap IMS CAD file
containing the desired wireframe is selected via the Wireframe dialog box (Figure 5). The desired
wireframe is then selected from the drop down list.
Figure 5: Wireframe input dialog box
Page 21
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Output Drillhole File
All types require an output drillhole file specified via the Output dialog box (Figure 6).
Figure 6: Output drillhole file dialog box
Page 22
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Output Report Files
Composite types 4, 5, 6, 7, 8, 9 and 10 will include the details of output drillholes in the report files in
one or more formats (.rpt, .xls, .csv .doc) if the user provides the file names for the required format in
Reports dialog box (Figure 7).
Figure 7: Output report files dialog box
Page 23
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Input Parameters
The required parameters for each compositing option, is given into MineMap IMS by set of dialog
boxes given in Table 1.
Table 1: Dialog boxes present for each compositing type
Type
Type of Composite
Dialog boxes Presented
1
Composite
by
stratigraphies
2
Composite by stratigraphy
name
None
3
Composite by lithology
Lithology For Compositing
4
Composite waste, then Assay Compositing Parameters
composite everything up to
Weight the Composite Assays
a cut off band
5
Composite waste, then flag Assay Compositing Parameters
everything up to a cut off
Weight the Composite Assays
band
6
Composite
contiguous Assay Compositing Parameters
waste and ore bands
Weight the Composite Assays
model
Weight the Composite Assays
Weight the Composite Assays,
7
Range Criteria and
Stratify using composite
ranges
((Composited Assay Ranges for Stratifying Holes and
Break-out Criteria for Each Defined Strat Unit) or
Single Range Criteria))
Weight the Composite Assays,
Range Criteria
8
Stratify,
then
economic rationale
((Composited Assay Ranges for Stratifying Holes and
apply Break-out Criteria for Each Defined Strat Unit) or
Single Range Criteria))
Economic Parameters,
Quality for Dollar Value
Relative Density Assay
9
Stratify and
thickness
maximise Weight the Composite Assays and
Stratify and Maximise Thickness
Page 24
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Weight the Composite Assays and
10
Create fixed length samples
Create Fixed Length Samples
11
Write samples inside a
Wireframe
wireframe
Page 25
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Weight the Composite Assays
Assays such as an assemblage of "heavy mineral" (e.g. rutile, monazite, etc.) may require weighting.
The assay used for weighting is specified via the Weight the Composite Assays dialog box (Figure 8).
Figure 8: Weighting assays
NOTE: This dialog box will be presented, only if there are multiple assays in the input drillhole file.
Page 26
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Lithology for Compositing
The lithology type required for compositing is specified via the Lithology for Compositing Dialog box
(Figure 9).
Figure 9: Lithology selection
NOTE: Lithology information must be incorporated into the drillhole file. If no lithology information
is present then no compositing occurs.
Page 27
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Assay Compositing Parameters
Down hole cut-offs are used in the ‘Optimum Depth’ method which is type 4 (Composite Waste, then
Composite Everything up to a Cut off Band). The cut-off parameters are specified via the Assay
Compositing Parameters dialog box (Figure 10).
Figure 10: Assay compositing parameters for waste band and ore band
The Composite Waste, then Composite Everything up to a Cut off Band option uses the following
compositing algorithm:
(1)
An optional waste band is first defined where each sample is tested (starting from the top of
the hole) against the break-out grade criterion. If a sample exceeds this grade, then successive
samples are tested to ensure that their composited grade can be sustained (i.e. grade > break-out
grade). The number of successive samples tested depends on the user-defined minimum thickness. If
the composited grade can be sustained, then the Waste Band is the region from the top of the hole to
the top of the successful composite. If the grade cannot be sustained, then the algorithm continues
checking each sample against the break-out grade.
(2)
The composited waste defined in the above step must not exceed the maximum thickness. If
the waste does exceed this value, then the floor of the band is set to the maximum thickness (depth).
(3)
The samples below the Waste Band are composited using an algorithm to ascertain the
optimum depth of the ore. Here, two tests are performed. The first is to start at the bottom of the hole
and work upwards until a grade is found which exceeds the uphole sample cut-off. Once a sample is
Page 28
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
found, the second test is enforced which is to composite the hole from this sample up to the floor of
the waste band. If the composited grade exceeds the average grade, then the Ore Band is deemed to
be composited. If, however, it does not pass the average grade criterion, then the algorithm reverts
back to the first test, and continues to look up the drillhole for another sample that exceeds the uphole
sample cut-off.
(4)
If the Ore Band cannot be created, then the Waste Band is ignored and nothing is output for
the hole.
Type 5 (Composite Waste, then Flag Everything up to a Cut off Band) is the same as the above
except each sample that lies within the composite intercept, at the parameters specified, is written out
in drillhole format.
NOTE: If you do not wish to have a "waste" band defined at the top of the drillhole in the
compositing process, insert 0 for the values associated with the Waste Band.
The cut-off parameters for type 6 (Composite Contiguous waste and ore Bands) are specified via the
Assay Compositing Parameters dialog box (Figure 11).
Figure 11: Assay compositing parameters for waste band to ore band transition
Page 29
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Compositing ranges
Type 7 (Stratify using composite ranges) requires a number of stratigraphic criteria that can be used
to isolate the composites in the drillhole data. These are specified via a series of dialog boxes that
begins with the Range Criteria dialog box (Figure 12).
Figure 12: Range criteria selection
Page 30
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Multiple Range Criteria
If you choose to apply multiple range criteria then the Composited Assay Ranges for Stratifying Holes
dialog box (Figure 13) will be displayed. Up to twenty stratigraphic criteria can be defined and the
names do not have to be unique nor do they have to be consistent with the input drillhole data.
The order in which you provide the stratigraphic names is the same order as that in which the
stratigraphies are created, namely bottom up.
Figure 13: Multiple assay Ranges for stratifying holes
There are four options at the bottom of the dialog box:

Create implied waste units creates a composited "waste" unit between composited stratigraphies
of samples that do not meet the compositing criteria.

Create waste at end of hole creates a composite waste unit at the end of hole made of samples
that did not meet the compositing criteria.

Write out individual samples assigns a stratigraphic name to samples that pass the compositing
criteria but instead of compositing the samples into a new interval, writes them out individually.
This option essentially allows you to name samples.

Exclude break-out samples from further composites generates definite breaks in stratigraphy if
there are any break out samples that pass the criteria.
Page 31
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
The next dialog box (Figure 14) presented requires break-out information for the stratigraphies
defined above. The "break-out" algorithm is discussed in the section titled The Break-out Criterion.
It outlines the use of the following three parameters:
 Break-out sample grade
 Average grade
 Thickness over which to test the average grade
Figure 14: Break-out criteria for each assay
Page 32
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Single Range Criteria
If you choose to apply single range criteria then the Single Range Criteria dialog box (Figure 15) is
displayed.
Figure 15: Single assay based stratifying
There are two options at the bottom of the dialog box:

Create implied waste units creates inferred "waste" units between the composited stratigraphies
that do not meet the compositing criteria.

Create waste at end of hole creates a waste unit at the end of hole made of samples that did not
meet the compositing criteria.
The parameters specified here will be applied repeatedly, up to 20 times per hole.
Page 33
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Economic Parameters
Type 8 (Stratify, then apply economic rationale) is an extension of the stratification algorithm
discussed above for type 7 (Stratify using composite ranges).
The same test criteria specified in type 7 are imposed to determine stratified intercepts (ore and waste)
for each drillhole.
NOTE: At least two assays are required in the drillhole file: the assay/quality of interest and a relative
density assay.
These intercepts are then tested using an economic rationalisation algorithm to determine whether
they contribute to a positive cumulated dollar value for the hole. This is done by first assigning each
composited intercept a net dollar value based on cost parameters specified by the user via the
Economic Parameters dialog box (Figure 16).
Figure 16: Assigning economic parameters
There are two more dialog boxes presented on choosing <Next>. Map the drillhole assays that will be
used for the “Ore” and RD classes as defined below:
Page 34
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
If the composite is ore, the net value is:
Equation 1: Net value if composite is ore
If the composite is waste, the net value is negative and is:
Equation 2: Net value if composite is waste
A cumulative dollar value is then calculated for each intercept in the hole, based on each intercept's
net value. MineMap IMS then searches up the hole until it finds a positive cumulative dollar value at
which point all intercepts to the top of the hole will produce a profit.
Page 35
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Stratify and Maximise Thickness
Type 9 (Stratify and maximise thickness), requires parameters that are specified via the Stratify and
Maximise Thickness dialog box (Figure 17).
Figure 17: Stratify and maximise thickness
This option expands the composite to match a target grade. The composites consider adjacent samples
before moving on. If at any time an additional sample forces a break out below the target, the
composite will be stopped.
Page 36
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Create Fixed Length Samples
The samples in a given drillhole are composited “downhole” into lengths determined by the user in
the Create Fixed Length Samples dialog box (Figure 18).
Figure 18: Assigning fixed lengths and defining the residual
The assays at each interval are length weighted to create the new composited drillhole. This option
will split long samples and stop at unsampled intervals.
Page 37
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
OPERATION OF COMPOSITE DRILL DATA
Composite Drillholes Using a Model
Type 1 (Composite by model stratigraphies) allows you to composite drillhole data within a seam or
stratigraphic unit of a model. The roof and floor elevations are used to structurally delineate
boundaries for each composite, and the module will attempt to create a composite for each lamination
of the model as shown in Figure 19.
Figure 19: Samples intersecting a seam of a model
The compositing process uses length weighting on the samples to take into account those portions of
samples that intersect the seam roof/floor boundaries. The data can be further weighted by an assay
(such as relative density or, in the case of heavy mineral assemblages, the overall heavy mineral
percentage).
The cell size of the model is an important factor to be taken into consideration because the roof and
floor elevations are derived from the cells surrounding the sample intercept. A triangulation of the
surrounding cells is used to interpolate the elevation at the intercept, as shown in Figure 20, but this
algorithm assumes that the surfaces are linearly interpolated between cell centres, (i.e. an equation for
the surface of the triangle is derived and the elevation at any point of the triangle can then be
computed). If the roof or floor surfaces are erratic then smaller cell sizes will reduce the interpolated
distance.
Figure 20: Linear interpolation of cell elevations
Page 38
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
The example (Figure 21) shows a drillhole passing through a low resolution (large cell) model and
also through a high resolution (small cell) model. The net effect is a slightly different composite
interval because the changes in elevation between large cells would be more marked than the
elevation changes between small cells.
Figure 21: Cell sizes affect the resolution of the composite
Page 39
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Composited Grade of an Assay
The composited grade of assays that use weighting is:
Where Assayx is the xth assay
Composited Gradex is the composited grade of the xth assay
Wgt.Assay is the assay used for weighting
Equation 3: Composited grade of assay that uses weighting
Page 40
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Composite Based On Drillhole Stratigraphy
Type 2 (Composite by stratigraphy name) is one of the simplest types of compositing. It requires that
stratigraphy names be included within the drillhole file. This option mainly applies to laminar type
mineral deposits such as mineral sands or coal.
If you require some weighting on the samples, you can use the Lithology Composite option. Just
create a lithology table from the assay/stratigraphy table in your data base and create a new drillhole
file.
Page 41
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Obtaining An Optimum Depth
Types 4 (Composite waste, then composite everything up to a cut off band) and 5 (Composite waste,
then flag everything up to a cut off band) with Waste = 0 find an optimum depth based on average
grade criteria. These types are principally used in heavy mineral deposits where the drillhole has
regular one metre samples on a short (say 20m) drillhole.
Two tests are performed:
1. Start at the bottom of the hole and work upwards until a grade is found which exceeds the
sample cut-off criterion.
2. Composite the hole from this sample up towards the collar. If the composited grade exceeds
the average grade criterion, then the hole is deemed to be composited. If, however, it does not
pass the average grade criterion, then go back to the first test, and continue to look up the
drillhole for another sample that exceeds the sample cut-off criterion.
The two tests are shown in Figure 22.
Figure 22: The two criteria that define an optimum depth
Page 42
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Optimum Depth Incorporating Surface Waste
Types 4 (Composite waste, then composite everything up to a cut off band) and 5 (Composite waste,
then flag everything up to a cut off band) with Waste > 0 have options to include a waste band for
the surface. That is, the compositing will begin from the top of the hole and work down, identifying
an upper band of low grade samples as waste, whilst trying to determine the top of the ore.
Each sample is tested (starting from the top of the hole) against the break-out grade. If a sample
exceeds this grade, then successive samples are tested to ensure that their composited grade can be
sustained (i.e. grade > break-out grade). The number of successive samples tested depends on the user
defined minimum thickness. If the composited grade can be sustained, then the Waste Band is the
region from the top of the hole to the top of the successful composite. If the grade cannot be sustained,
then the algorithm continues checking each sample against the break-out grade.
The result is the creation of a waste band or stratigraphy at the top of the drillhole, based on userdefined criteria. The composite continues as outlined in Obtaining an Optimum Depth, starting at
the base of the drillhole, searching up to the floor of the "waste" band previously defined.
Page 43
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Using Stratification Criteria
Cut-off and average grade criteria are used to isolate a number of stratigraphies up the hole in types 7
(Stratify using composite ranges), 8 (Stratify, then apply economic rationale) and 9 (Stratify and
maximise thickness). The effect is to produce a number of seams that meet the criteria as shown in
Figure 23.
You can define as many as twenty stratigraphies, each with their own criteria, to be tested against the
sample data.
Figure 23: Stratigraphies isolated from the drillhole column
For each set of stratification criteria, three generalised tests (for which there are sub-tests) are
performed as the composite moves up the drillhole:
(1)
Search up the hole until a grade is found that meets a starting criterion, in which case the floor
of the stratigraphy is established;
(2)
Continue up the hole until the composite fails to meet an average grade criterion; or
(3)
Continue until a break-out criterion is met, in which case the stratigraphy is defined.
When the stratigraphy is defined (and composited), the process continues using the next stratigraphic
criterion and applies it to the remaining portion of the hole, as per the three steps above.
When a break-out sample is found, or when the composited grade fails to meet the average grade test,
a roof is established which does not include the offending sample.
Page 44
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Each of these steps is covered in detail below.
The Start Criterion
The Average Grade Criterion
The Break-out Criterion
The Economic Criterion
The Maximise Thickness Criterion
Page 45
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
The Start Criterion
The criterion to start the stratification up the drillhole has two tests:
The grade of the sample must pass the Start Sample Criterion;
The composited grade over the next few samples that constitute a thickness greater than a user defined
thickness must pass The Average Grade Criterion.
In Figure 24, an example is provided in which a stratigraphic unit is started. The samples are 1m thick
and the stratification criteria are:
1) Start sample > 5%
2) Average Grade > 3%
3) Minimum Thickness = 3m
The bottom two samples do not pass the Start Sample Criteria even though they pass the Average
Grade Criteria over 3 metres. The third sample from the bottom, however, passes both tests, and
therefore is the floor of the stratigraphy.
Figure 24: Start criterion test
Page 46
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
The Average Grade Criterion
The composite is continued up the hole until an adjacent sample to the ongoing composite forces the
overall composite to fail The Average Grade Criterion. The preceding sample is then used to
determine the roof of the stratigraphy. This, however, is not the only test for the roof since The
Break-out Criterion is also tested and is described in the following section. Either test can impose a
roof.
Page 47
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
The Break-out Criterion
The Break-out Criterion is another test that is imposed in an attempt to determine the roof. If a sample
passes this criterion then the preceding sample is used to determine the roof. There are two tests that
make up the break-out condition:
 The grade of the sample must pass the Break-out Sample Criterion (which in most cases is a "less
than" condition).
 The composited grade over the next few samples which make up a user-defined thickness must
pass an Average Grade Criterion (which in most cases is also a "less than" condition).
The Figure 25 illustrates the break-out test, wherein the following criteria were used on 1m samples:
1) Break-out sample < 1.5%
2) Average grade < 3% over a thickness of 3m
The 1.2% sample illustrated in this example passes the Break-out Sample Criterion (which tests for
grades less than 1.5%). The next three metres are composited and found to be less than the Average
Break-out Grade, and thus, this test also returns a true condition. The roof of the stratigraphy is then
the top of the preceding sample. This is despite the fact that when the 1.2% sample is bulked with the
total composite of the stratigraphy, the average grade is greater than the required minimum average
grade imposed by The Average Grade Criterion.
Figure 25: Break-out criterion test
Page 48
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
The Economic Criterion
Type 7 (Stratify using composite ranges) creates a number of composited intercepts for a drillhole.
These intercepts can be further tested for overall economic suitability by passing them through an
economic rationalisation algorithm to determine whether they contribute to a positive cumulated
dollar value for the hole as follows:
1. Assign each composited intercept a net dollar value based on cost parameters specified by the
user.
2. Accumulate “down-hole” dollar values for each intercept in the hole, based on each
intercept's net value. Search up the hole until a positive cumulative dollar value is found at
which point all intercepts to the top of the hole will produce a profit.
Page 49
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
The Maximise Thickness Criterion
Type 9 (Stratify and maximise thickness) maximises the thickness of a composite interval for a
desired grade.
All adjacent samples that satisfy the required parameters are composited. Further samples are
included to maximise the thickness while maintaining a desired grade. This is achieved by considering
the adjacent samples in the ongoing composite, and including portions of the best assay value samples
preferentially, until the composite reaches the nominated grade.
In summary, this option interpolates the upper and lower boundaries of a given sample for a constant
grade.
Page 50
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Fixed Length Samples
Type 10 (Create fixed length samples) weights the original sample grade by length, converting them
to a nominated sample length. The compositing works down the hole from the first sample. However,
if the drillhole has been sampled irregularly (i.e. there are unsampled intervals) then the compositing
starts again from the next sample. (Figure 26)
Figure 26: Unsampled intervals in creating fixed length samples
If specific sample intervals are needed to be composited, they can be manipulated in the drillhole
database and a drillhole file produced to be composited (e.g. all samples above 0.5g). This method
will then produce fixed width samples down the hole. The resulting drillhole file can be read into the
database.
Page 51
Intelligent Mining Software “Solutions”
MineMap IMS - Composite Drill Data
Samples Inside a Wireframe
Type 11 (Write samples inside a wireframe) creates a drillhole file of samples enclosed by a closed
wireframe (solid).
Page 52