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Exploration Chapter 15: Working with Drillholes

Chapter 15

Working with Drillholes

In This Chapter

• Introduction• General Procedures• Loading Drillhole Data• Selecting Drillhole Intersects• Displaying Drillhole Data

Introduction

A drillhole workspace holds information that is collected along lines inthree dimensions. Drillholes are defined by a single coordinate at oneend of a line and by directional data (for example, dip angles andazimuths) measured at intervals along the line. Information is locatedalong the line, either at points defined by distance measurements alongthe line, or in intervals defined by starting and ending distances alongthe line. Drillhole data is always three-dimensional.

You can use the commands in the Drillhole menu to display data fromdrillhole or traverse workspaces. Drillholes and traverses are displayedas trace lines. Data from any of the tables in the workspace can bedisplayed in a variety of ways at the collar location of each drillhole ortraverse, or along the trace of each drillhole or traverse.

The Drillhole menu also provides you with a set of very flexiblecompositing tools to perform drillhole compositing and drillhole/solidcompositing. See Chapter 16: Drillhole Compositing for details.

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Section III: Drillholes Gemcom for Windows

The Drillhole menu provides several alternatives for displayingdrillhole information. You can do the following:

• View drillholes in two or three dimensions.

• Use drillholes as references for polyline editing.

• Intersect drillholes with solids or surfaces (in conjunction withthe Solid and Surface menus).

There are three submenus that deal with loading, selecting anddisplaying drillhole data:

• Data. The commands in this submenu allow you to define wherethe drillhole data is to be loaded from, and to load the data.

• Select. The commands in this submenu activate and deactivatedrillhole intersects, and define the drillhole intersect points forselection and snapping.

Figure 15-1: A drillhole data display

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• Display. The commands in this submenu define how drillholedata is displayed on-screen, and allow you to query points onthe drillhole for information.

Using Drillholes

You can use drillhole data to perform many tasks, such as thefollowing:

• View drillhole traces and interval information.

• Snap to drillhole traces for on-screen polygon and linedigitizing.

• Create surfaces using drillhole intersect information.

• Snap to drillholes for setting 3D target and camera positions.

• Snap to drillholes for setting planes for digitizing/TINoperations.

• Validate drillhole interval information.

Viewing Drillhole Data

Gemcom for Windows allows you to view drillhole traces along withcollar and interval information from user-specified fields. Colourprofiles are supported for display of all interval information.Drillholes can be viewed in 3D, where drillholes can be rendered asa solid "tube", or in 2D (clipped against a view corridor andprojected onto any plane).

On-screen Polygon and Line Digitizing

During all 2D and 3D digitizing, you can "snap" onto drillholecollars or intervals to obtain an exact coordinate value and toposition the graphics cursor exactly on the drillhole point. Thiscapability is useful for ensuring that digitized data honours the

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drillhole information even though the screen resolution wouldnormally introduce some numerical rounding error, or when thedrillhole point does not exactly fall on the plane on which thedigitizing is taking place.

Creating Surfaces

Gemcom for Windows allows you to activate certain drillhole points(for example, collar locations, FROM values, or selected intervals) tocreate surfaces using the 3D coordinate values of the selectedpoints. This allows you to form both topographic surfaces (fromcollars) and faults or seams (from interval points). Gemcom forWindows allows you to create surfaces relative to any plane. Forexample, you can create faults through a "best-fit" plane from allselected data points.

Setting 3D Target and Camera Positions

Gemcom for Windows allows you to "snap" onto drillhole points forsetting both the target and camera positions. This is very usefulwhen setting views for 3D rendering and plotting.

Setting Planes

You can select any three data points from a set of drillhole data toset a plane for defining an inclined section, viewing, all subsequent2D/3D polyline digitizing, or surface creation.

Validating Drillhole Interval Information

You can select any drillhole interval in both 2D and 3D modes, andGemcom for Windows will report information about the interval.This can be used in conjunction with the various drillhole displayoptions as a powerful data validation tool.

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General Procedures

Use the following steps to display drillhole data:

1. Create or assign your project with either the File }} Projects }}Create New Project command or the File }} Projects }} Assign ExistingProject command.

2. Define colour profiles using the File }} Edit Profiles }} Define ColourProfiles command.

3. Define the workspace structure using the Workspace }} Create orModify Workspace command.

4. Enter your records into the drillhole workspace (using theWorkspace Editor, the import or merge tools, or the digitizingfacilities, etc.).

5. Define a drillhole display profile using the Drillhole }} Display }}Define Display Profiles command or when loading the drillholes.

6. Optionally, define a drillhole loading profile using the Drillhole }}Data }} Define Loading Profiles command or when loading thedrillholes.

7. Load the workspace data using the Drillhole }} Data }} LoadDrillholes command. This command allows you to specify whichdisplay profile and loading profile to use.

8. Specify the location of drillhole intersects for selection andsnapping with the Drillhole }} Select }} Select and Snap Settingscommand.

Once you have set up your profiles and data, you can simply use thefollowing steps:

1. Assign or reassign your project with either the File }} Projects }}Assign Existing Project command or the Drillhole }} Data }} ReassignWorkspace Project command.

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2. Load the workspace data using the Drillhole }} Data }} LoadDrillholes command. This command allows you to specify whichdisplay profile and loading profile to use.

3. Specify the location of drillhole intersects for selection andsnapping with the Drillhole }} Select }} Select and Snap Settingscommand.

Project View Area

The Drillhole menu makes use of the folder tree found in theProject View Area. The Project View Area is accessed by a buttonon the toolbar or under the Window menu. An introduction to theProject View Area can be found in Chapter 3: Getting Started,Volume I: Core.

The Project View folder tree provides a map of your projectstructure. You can right-click a project or workspace name (or icon)to access some applicable Drillhole menu commands. The specificcommands available for a workspace will depend on the currentdata loading status. There are also Properties information dialogboxes available for both projects and workspaces.

Loading Drillhole Data

Choosing the Data command on the Drillhole menu brings up asubmenu containing commands for loading, reloading or unloadingdata, and for defining loading profiles.

Drillhole data is loaded from the current workspace project, asdefined in the project paths (see Chapter 9: The File Menu, VolumeI: Core for more information), or as reassigned with the commandDrillhole } Data } Reassign } Workspace Project.

Your project database contains many workspaces organized by datatype. Each workspace is a series of tables in the database for aproject, namely a header table and various subtables. Drillhole data

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can be divided into different drillhole or traverse type workspaces ifdesired. You select the appropriate workspace in the Drillholemenu when loading drillhole data (and defining profiles). Selectinga workspace in the Workspace menu does not affect the Drillholemenu.

You can open more than one workspace at a time in the Drillholemenu. If you have two or more workspaces loaded, commands in themenu will present you with a list of loaded workspaces. Otherwise,commands operate on the selected workspace (or are greyed out ifno workspaces are loaded).

When you load drillhole data, you are making a copy of selectedrecords in selected tables and fields in computer memory.Therefore, changes to the drillhole data in the database (forexample, in the Spreadsheet Editor) will not be reflected on thescreen unless you reload your data.

Before the program can load any drillhole data, you must set upand select the following profiles:

• Drillhole display profile. This profile specifies how you wantto display the drillhole data including the fields you wish to seedisplayed down the drillhole trace, such as rock code and gradevalues. You can define display profiles when loading drillholeswith the Drillhole } Data } Load Drillholes command or withthe Drillhole } Display } Define Display Profiles command.You select a display profile while loading your data.

• Drillhole loading profile. This profile specifies the datatables and fields that you want to load into memory. You cansimply select the Automatic load profile when loadingdrillholes to have the program extract the necessary fields toload from those specified in the display profile. Or, if necessary,you can define the profile when loading drillholes with theDrillhole } Data } Load Drillholes command or with theDrillhole } Data } Define Loading Profiles command.

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Reassign Workspace Project

Choose this command to reassign the project that you want to usefor loading drillhole data. This operation will remove any drillholedata in memory. Note that your “workspace project” is yourdrillhole project.

To reassign your project, follow these steps:

1. Select Drillhole } Data } Reassign Workspace Project.

2. In the Select Project dialog box, highlight the drive where theproject you wish to load resides.

3. A list of projects stored on the selected drive will appear.Highlight the desired project folder and click OK.

This command is the same as selecting File }} Assign Project Paths andmodifying the Workspace Project.

Define Loading Profiles

A loading profile specifies the data tables and fields that you wantto load from the database into Gemcom for Windows’ memory.When loading drillhole data, it is easiest to simply use theAutomatic loading profile. Gemcom for Windows will load all ofthe data required by the display profile you select, as well as surveyinformation needed to display drillholes or traverses in 3D. Thus,you only need to use a loading profile in special cases when youwant to force the program to load these fields plus additional fieldsinto memory. You only need to specify the additional fields in theloading profile. Situations where you might want to define aloading profile include the following:

• You may want to switch between two or more display profilesfor a large amount of data. Instead of having to do time-consuming reloads, you can use a loading profile to load all thedata at the same time that will be required by the displayprofiles.

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• You may wish to have certain fields loaded so that you can seeinformation about them with the Display Intersect/TraceInformation commands, independent from the current displayprofile.

• If you will be using the Assign Grades to Solids fromDrillholes command, you must create a loading profile thatcontains the fields that will be used by that command. Thefields loaded will appear in lists when you are assigningworkspace fields to grade elements.

Note that drillhole loading profiles need not include any fields usedto define the geometry and location of the drillholes, for example,FROM, TO, DISTANCE, or LOCATION fields.

To define a drillhole loading profile, follow these steps:

1. Choose Drillhole }} Data }} Define Loading Profiles. The SelectWorkspace dialog box will appear. Specify a drillhole ortraverse workspace by clicking a workspace name in the list ofavailable workspaces and click OK.

Figure 15-2: Drillhole Loading Profile Editor dialog box

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2. The Drillhole Loading Profile Editor will appear, enablingyou to add, modify, and delete drillhole loading profiles andcopy them to and from other workspaces.

3. Click Add and enter a name of up to ten alphanumericcharacters for the profile. Be sure to use a unique name if youwill be working with multiple workspaces. Click OK.

4. The window in the centre of the editor, Fields Available,provides a tree view list of all tables in the workspace. You canview the fields within a table by clicking the plus sign alignedwith the table name. Click the minus sign to close the list.

The window on the right, Fields to Load, will contain all fieldsselected for the loading profile, identified by Table name andField name.

Assign the desired fields to the loading profile using thefollowing methods.

To add or remove an individual field from the loading profile:

• Select or deselect a field in the Fields Available window bydouble clicking the empty checkbox beside the field name. Atick mark appears in the checkbox when the field is selectedfor the loading profile. A tick mark will also appear in thecheckbox beside the related table.

To remove individual fields from the loading profile withinthe Fields to Load window, double click the Table columnentry for the particular field.

To add or remove an entire table from the loading profile:

• Select or deselect all fields in a table in the FieldsAvailable window by double clicking the empty checkboxbeside the table name. A tick mark always appears in thecheckbox when the table is selected for the loading profile.Note that if one or more (but not all) fields in the table havebeen already individually assigned to the loading profile,this action will simply reverse the selection of all fields.

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To remove all fields and tables from the loading profile:

• Click Clear All.

To place all fields in the workspace into the loading profile:

• Click Add All.

5. To add the fields required by one or more display profiles to theload profile, click Select Display Profiles. You will see a list ofpreviously defined display profiles for the current workspace.Click the profile name or, holding down the [Ctrl] key, click theprofile names. Click OK. The fields required by the displayprofile(s) selected will now appear in the current load profile.

6. Click Save to add the loading profile. Click Exit.

Load Drillholes

Choose this command to load drillhole data into the current worksession. You will need to select a drillhole loading profile and adrillhole display profile for the workspace. You select (andoptionally define) them within this command.

To load drillhole data, follow these steps:

1. Select Drillhole }} Data }} Load Drillholes. The Select Workspacedialog box will appear. Specify a drillhole or traverse workspaceby clicking a workspace name in the list of available workspacesand click OK.

2. In the Drillhole Load Settings dialog box that appears,choose the desired loading profile from the Load Profile list.You may select Automatic to have the program load thenecessary data as specified in the display profile, or you mayselect a previously defined loading profile. Only profiles that arevalid for the selected workspace will be listed. If you need todefine a loading profile, click Define. See “Define LoadingProfiles” on page 2386 for details.

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3. Select the desired display profile from the Display Profile list.Only profiles that are valid for the selected workspace will belisted. If you have not defined a display profile, click Define. See“Define Display Profiles” on page 2404 for details. Click OK.

4. In the Record Selection Options list, pick a method forselecting a subset of records to be loaded. Note that you can useSQL filters when loading drillhole data which are much fasterthan Gemcom filters. Refer to Chapter 4: Dialog Boxes, VolumeI: Core for more information on record selection, and Chapter 9:Filters and Key Indices in this volume for more information onSQL filters. Click OK.

5. Existing data in the current workspace is unloaded first. Then,a status box will indicate the number of holes and records beingprocessed. To halt the loading process, press [Esc]. You will thenbe asked to confirm that you want to terminate loading. ClickYes to plot all drillholes loaded so far, or on No to continueloading drillholes.

6. To open another drillhole workspace, repeat from Step 1.

Reload Drillholes

This command allows you to reload the most recently loadeddrillhole data using the same loading and display profiles, but adifferent record selection option. This is particularly useful if youwish to look at different subsets of the same drillhole workspace

Figure 15-3: Drillhole Load Settings dialog box

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using the same profiles. The most recently specified workspace,loading profile, and display profile are automatically selected foryou. If no drillholes have been loaded, this command is notavailable. If you have two or more workspaces open, you will beasked to select which workspace to reload.

Unload Drillholes

Choose this command to remove all drillholes from the work sessionand close the workspace. If no drillholes have been loaded, thiscommand is unavailable. If you have two or more workspaces open,you will be asked to select which workspace to unload.

Selecting Drillhole Intersects

Choosing the Select command on the Drillhole menu brings up asubmenu containing commands for selecting and deselectingdrillhole intersects from among the set of drillholes loaded in theworkspace. There are also commands for specifying the location andappearance of drillhole intersect points, and for saving activeintersects to an extraction file. Drillhole intersects are points usedfor many operations, such as surface creation.

A drillhole intersect can be any of the following:

• A position down a drillhole defined in a DISTANCE field

• A position down a drillhole defined in a LOCATION field

• A position down a drillhole defined in a FROM field

• A position down a drillhole defined in a TO field

You can use several methods to activate/deactivate drillholeintersects interactively for creating surfaces or for use in solidformation:

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• Using the mouse to select intersects manually

• Using selection criteria to select intersects by querying fields

• Using a clipbox to select intersects within a specific area

All Select submenu commands are additive. You will keep increasingthe number of active intersects each time you choose a Selectcommand. Be sure to deselect intersects when appropriate. You canalso select or deselect all intersects in the current drillhole workspace.

The Select and Snap Settings command allows you to control thelocation and appearance of drillhole intersect points for all selectioncommands and snapping operations. Because you can have fields frommultiple tables displayed, you must specify which table and field to useto determine the location of the intersect symbols. Generally when anintersect is activated, the symbol at the active location changes from adot to a cross. However, instead of having crosses displayed at theintersect points during selection, you can choose to have the drillholeintervals highlighted in a specified colour. You can also control the sizeand colour of the intersect symbols.

Select and Snap Settings

Use this command to control the location of drillhole intersectpoints and their behaviour when you select them in the Selectmenu, or snap to them (in other Gemcom for Windows menus). Theportion of the interval that you are highlighting on the drillholetrace is determined by the table and field (e.g., FROM, TO, orDISTANCE) specified in this command. The one exception is theSelect Drillhole Intersects by Field Value command which alsoallows you to specify the location for intersects.

Intersect points generally appear as dots when unselected and ascrosses when selected. You can specify the size and colour of the dotsand crosses, or, instead of using crosses, you can choose to highlightintervals with a specific colour when intersect points are selected.

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You can assign the location of the trace symbols (as defined in thecurrent display profile) as the location for the intersect symbols. Adot in the specified colour will overlap each symbol when it isunselected. When highlighted, a cross appears and the trace symboland the cross take on the selected colour (or the interval ishighlighted in the selected colour).

Note that there are options in the Display Settings command thatcan hide intersects.

You can always snap to the drillhole collars. If multiple workspacesare open, snapping to drillholes throughout Gemcom for Windowsoperates as though all workspaces are simultaneously selected.

To define the select and snap settings, follow these steps:

1. Select Drillhole }} Select }} Select and Snap Settings. The SelectWorkspace dialog box will appear if you have more than oneworkspace open. Specify a drillhole or traverse workspace byclicking a workspace name in the list of available workspacesand click OK.

2. Enter the following parameters:

• Table Name. Choose the table which has the intervals youwant to use from all tables listed in the workspace or choosethe Trace Symbol Table. This option automatically usesthe position of the trace symbols (as defined in your displayprofile) as the position for the intersect symbols. If you enterthe header table for the table name, only one intersect isdrawn because the header table has only one record perdrillhole.

• Position. If you are not using the Trace Symbol Table,select one of the options for the position of each intersectsymbol within each trace interval:

If you are using the header table:

◊ Collar. This option is selected for you. The intersectsymbols will be placed at the drillhole collars.

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If you are using an interval table:

◊ From. Select this option to position the intersectsymbols at the trace interval FROM values.

◊ Middle. Select this option to position the intersect symbolsbetween the FROM and TO values of the trace intervals. Thisoption may be the best for easily identifying which intervalyou are selecting or snapping to.

◊ To. Select this option to position the intersect symbolsat the trace interval TO values.

◊ From and To. Select this option to position theintersect symbols at both the FROM and TO values of thetrace interval.

If you are using a distance or point secondary table:

◊ Distance/Location. Select this option to position theintersect symbols at the DISTANCE/LOCATION values downthe trace.

Figure 15-4: Select and Snap Settings dialog box

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◊ Middle. Select this option to position the intersectsymbols between the DISTANCE/LOCATION values downthe trace.

• Symbol Size. This option determines the width of thecrosses that are displayed when the intersect symbols areselected. The size of the dots (representing the unselectedintersects) will be proportional. Enter a size in themeasurement units of your project (i.e., feet or metres).

• Highlight Selected Intervals. Check this option to havethe intervals highlighted instead of the intersect pointsthemselves when you select an intersect.

• Colours When Background is Black:

◊ Selected Colour. Choose a colour for the activeintersect symbols (the crosses) from the standard 16Gemcom colours.

◊ Unselected Colour. Choose a colour for the inactiveintersect symbols (the dots) from the standard 16Gemcom colours.

• Colours When Background is White:

◊ Selected Colour. Choose a colour for the activeintersect symbols (the crosses) from the standard 16Gemcom colours.

◊ Unselected Colour. Choose a colour for the inactiveintersect symbols (the dots) from the standard 16Gemcom colours.

3. Click OK. You may be asked to confirm the loading of new datafrom the workspace.

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Select Drillhole Intersects Manually

Choose this command to activate or deactivate individual intersectsmanually.

1. Select Drillhole }} Select }} Select Drillhole Intersects Manually. TheSelect Workspace dialog box will appear if you have morethan one workspace open. Specify a drillhole or traverseworkspace by clicking a workspace name in the list of availableworkspaces and click OK.

2. Click an inactive intersect point to select it or on an activeintersect to deselect it.

3. Repeat Step 1 until all desired points have been selected ordeselected.

Select Drillhole Intersects by Field Value

Choose this command to select or deselect all drillhole intersectpoints where the contents of a field match the selection criteria thatyou define. You specify the location of the intersects within thiscommand.

1. Select Drillhole }} Select }} Select Drillhole Intersects by Field Value.The Select Workspace dialog box will appear if you have morethan one workspace open. Specify a drillhole or traverseworkspace by clicking a workspace name in the list of availableworkspaces and click OK.


• • Table Name. Choose the table that contains the field to useas the basis for intersect selection or deselection from alltables listed in the workspace. Note that this valueoverrides (and updates) the Table Name parameter inSelect and Snap Settings.

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• Field Name. Pick the field to use to determine intersectselection or deselection from the list of available numeric ortext fields. The following entry fields will appear:

To specify intersects using a text field:

◊ Text. Enter the text string for the field value to matchin order for an interval to qualify. Wild card characters(? and *) can be used and text is case-sensitive.

To specify intersects using a numeric field:

◊ Lower. Enter the inclusive lower bound for the range offield values to match for an interval to qualify.

◊ Upper. Enter the inclusive upper bound for the range offield values to match for an interval to qualify.

• • Position. Select one of the following options to specify thelocation for the intersect symbols within each qualifyinginterval after being selected or deselected. When selectingintersects, the intersect symbol is a cross; when deselecting,

Figure 15-5: Selection by Field Values dialog box

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the symbol returns to a dot. Note that this value overrides(and updates) the Position parameter in Select and SnapSettings.


◊ Collar. This option is selected for you. The intersectsymbols will be placed at the drillhole collars.

If you are using an interval secondary table:

◊ From. Select this option to place the intersect symbolsat the trace interval FROM values.

◊ Middle. Select this option to place the intersect symbolsbetween the FROM and TO values of the trace intervals.

◊ To. Select this option to place the intersect symbols atthe trace interval TO values.

◊ From and To. Select this option to place the intersectsymbols at both the FROM and TO values of the traceintervals.

If you are using a distance or point secondary table:

◊ Distance/Location. Select this option to place theintersect symbols at the DISTANCE/LOCATION values downthe trace.

◊ Middle. Select this option to place the intersect symbolsbetween the DISTANCE/LOCATION values down the trace.

• Occurrence. Specify which intersect to select or deselect ifmore than one intersect in a drillhole meets the selectioncriteria. Select one of the following four options:

◊ All. This option specifies every qualified intersect.

◊ First. This option specifies the qualified intersectclosest to the collar.

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◊ Nth. This option specifies the nth qualified intersectfrom the collar. If you select this option, you must alsoenter the Number parameter.

◊ Last. This option specifies the qualified intersectfurthest from the collar.

• Number. If you selected the Nth option for Occurrence, youmust enter a number to indicate the position from the collarof the desired intersect.

• Selection. Specify whether to select or deselect theintersect points specified above.

3. Click OK. You may be asked to confirm the loading of new datafrom the database, if necessary. Any newly selected intersectswill be added to any currently active intersects.

Select Drillhole Intersects Inside Clipbox

Choose this command to activate all intersects within adynamically created 2D clipbox.

1. Select Drillhole }} Select }} Select Drillhole Intersects Inside Clipbox.The Select Workspace dialog box will appear if you have morethan one workspace open. Specify a drillhole or traverseworkspace by clicking a workspace name in the list of availableworkspaces and click OK.

2. Anchor one corner of the clipbox by moving the graphics cursorto the desired location and clicking the left mouse button.

3. By moving the mouse, expand the box until it encloses all theintersects that you wish to activate.

4. Click the left mouse button when the clipbox is the desired size.All enclosed intersects will be activated.

5. If desired, repeat Steps 2 to 4 for another clipbox.

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This command will stay active until you select another editing orselection mode command, or until you press the [Esc] key.

Deselect Drillhole Intersects Inside Clipbox

Choose this command to deactivate all intersects within adynamically created 2D clipbox.

1. Select Drillhole }} Select }} Deselect Drillhole Intersects Inside Clipbox.The Select Workspace dialog box will appear if you have morethan one workspace open. Specify a drillhole or traverseworkspace by clicking a workspace name in the list of availableworkspaces and click OK.

2. Anchor one corner of the clipbox by moving the graphics cursorto the desired location and clicking the left mouse button.

3. By moving the mouse, expand the box until it encloses all theintersects that you wish to deactivate.

4. Click the left mouse button when the clipbox is the desired size.All enclosed intersects will be deactivated.

5. If desired, repeat Steps 2 to 4 for another clipbox.


Select All Drillhole Intersects

Choose this command to activate all intersects on all drillholes inthe current drillhole workspace. If you have two or moreworkspaces open, you must select the workspaces individually.

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Deselect All Drillhole Intersects

Choose this command to deactivate all intersects on all drillholes inthe current drillhole workspace. If you have two or moreworkspaces open, you must select the workspaces individually.

Save Active Intersects to Extraction File

Select this command to save all active drillhole intersect locationsto an extraction file.

1. Select Drillhole }} Select }} Save Active Intersects to Extraction File.The Select Workspace dialog box will appear if you have morethan one workspace open. Specify a drillhole or traverseworkspace by clicking a workspace name in the list of availableworkspaces and click OK.

2. In the dialog box which appears, choose the directory where youwish to store the point extraction file.

3. Enter the file name. It will automatically be assigned the .MEX

extension. Click Save.

4. Enter a header of up to 55 alphanumeric characters to identifythe contents of the extraction file and click OK.

5. A status window will inform you of the number of points savedto the extraction file. Click OK to close the window and proceed.

Displaying Drillhole Data

Selecting the Display command in the Drillhole menu brings up asubmenu containing commands for displaying drillhole information.You define drillhole display profiles that determine how you want todisplay the trace and interval data for each drillhole. You can controldisplay settings that override the profile parameters or turn on or offspecific components of the drillhole display. Other settings allow you to

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define distance markings down the trace and specify how drillholeswill appear in rendered mode. As well, you may query drillhole datainteractively by picking points on the trace with the mouse to displaydetailed downhole information onscreen.

There are five main elements of the drillhole display that you cancustomize in the display profile: the drillhole name, the collarsymbol, the trace symbols, the trace line itself, and the traceannotation. All elements are optional, and can be displayed in anycombination.

The trace of each hole can be displayed as a “thin” 3D polyline or asa “thick” trace with or without colour-coded interval data. Thedrillhole name can appear at the drillhole collar or toe. In additionto a collar symbol, you can have symbols at specific intervallocations down the trace.

The trace annotation can be information from up to 16 fields, fromany of the tables. You can display the annotation on either side ofthe trace or place it at the top and bottom of trace intervals. This is

Figure 15-6: 3D view of “thick” traces with annotation

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useful if, for example, you are displaying trace symbols withouttraces. You can also choose to mark trace intervals with ticks.

The colours of the collar and trace symbols, the trace annotation,and the trace line itself can all be varied depending on values inspecified fields.

When a drillhole trace is drawn, some symbols get drawnautomatically: a diamond shape appears where the drillhole crossesthe active plane; arrow pointers appear where the drillhole entersand exits the corridor; a short perpendicular line indicates the toeof the hole, a default Q_circle symbol indicates the collar of thehole.

When you choose not to display any drillhole traces or collarsymbols, a small green dot is drawn at the collar location.

Figure 15-7: 2D view of trace symbols with annotation

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Define Display Profiles

Choose this command to create a display profile to specify how youwant to display the traces, the symbols, and the annotation for thedrillhole data. You must define at least one display profile beforeyou can load any drillhole data. Any colour profiles needed must bedefined (in the File menu) before you can define a drillhole displayprofile.

You can easily change the way drillhole data is displayed byselecting a different display profile at any time after the drillholedata has been loaded. As well, if you make changes to the currentdisplay profile, any active data will be updated accordingly. Inthese cases, you may be asked to confirm the loading of new datafrom the database if necessary.

To define a drillhole display profile, follow this procedure:

1. Select Drillhole }} Display }} Define Display Profiles. The SelectWorkspace dialog box will appear. Specify a drillhole ortraverse workspace in the list of available workspaces byclicking a workspace name and click OK.

Figure 15-8: Drillhole Display Profile Editor (Symbol tab)

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2. The Drillhole Display Profile Editor will appear, enablingyou to add, modify, and delete drillhole display profiles, andcopy them to and from other workspaces. Any previouslydefined profiles that are valid for the selected workspace will belisted.

3. Click Add. Enter a name of up to ten alphanumeric charactersfor the profile. Be sure to use a unique name if you will beworking with multiple workspaces. Click OK.

4. If necessary, click the Symbol tab. Enter these parameters:

• Description. Enter a brief description for the profile.

• Show Hole ID. Check this option to display theinformation from the HOLE-ID field at the collar or toe of thedrillhole. Note that if the actual collar or toe of a drillhole isoutside the corridor, Hole ID will be displayed at theapparent collar or toe. Enter the following parameters tospecify how the drillhole name will be displayed:

◊ At. Specify whether to display the drillhole Hole IDabove the collar or below the toe of the drillhole trace.You may want to specify Toe in underground drillingsituations where many collars share one location.

◊ Height. Enter the character size for the annotation inthe measurement units of your project (i.e., feet ormetres).

◊ Colour. Choose a colour for the annotation from the 16standard Gemcom colours or choose As Trace to use thesame colour as the trace. When you are using a colourprofile for the trace, the As Trace option will assign thecolour of the first interval.

• Show Collar Symbols. Check this option to display acollar symbol. Enter the following parameters to specify howthe symbol will be displayed:

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◊ Type. Pick the type of symbol from among the 16standard Gemcom symbol types.

◊ Size. Enter the size for the symbols in the measurementunits of your project (i.e., feet or metres).

◊ Colour. Choose a colour for the symbol from the 16standard Gemcom colours or choose As Trace to use thesame colour as the trace. When you are using a colourprofile for the trace, the As Trace option will assign thecolour of the first interval.

◊ Colour By Field Value. Check this option to vary thecolour of the collar symbol depending on a value in aspecified field. This option will override the Colourparameter. Enter the following additional parameters todetermine the symbol colours:

Table. This is the name of the header tablein the specified drillhole workspace.

Field. From the list of available numeric ortext fields, select the name of the fieldcontaining the data you wish to use todetermine the symbol colour.

Profile. From the list of colour profilesdefined for the specified field type, select thecolour profile to which you wish to map thespecified field.

• • Show Trace Symbols. Check this option to displaysymbols at trace intervals. Enter the following parametersto specify how the symbol will be displayed:

◊ Type. Pick the type of symbol from among the 16standard Gemcom symbol types.

◊ Size. Enter the size for the symbols in the measurementunits of your project (i.e., feet or metres).

Page 2407


◊ Colour. Choose a colour for the symbols from the 16standard Gemcom colours or choose As Trace to use thesame colour as the trace. When you are using a colourprofile for the trace, the As Trace option will assignthose colours if you specify the same table for the tracesymbols and the trace line.

◊ Table. Pick the name of the table containing the traceintervals you wish to display from the list of tablesavailable in the specified drillhole workspace. If you willbe using Colour By Field Value, this table must alsocontain the field you wish to use to determine thesymbol colour.

◊ Position. Select one of the following options for thelocation of each trace symbol within each trace interval:


Collar. This option is selected for you. Thetrace symbols will be placed at the drillholecollars.

If you are using an interval secondary table:

From. Select this option to position the tracesymbols at the trace interval FROM values.Note that the first symbol will overlap withthe collar symbol (if applicable).

Middle. Select this option to position thetrace symbols between the FROM and TO

values of the trace intervals.

To. Select this option to position the tracesymbols at the trace interval TO values.

From and To. Select this option to positionthe trace symbols at both the FROM and TO

values of the trace intervals. Each FROM

symbol will simply be overlapped by a TO

Page 2408


symbol with the exception of the first FROM

and the last TO. Thus, this option ensuresthat you will have a symbol both at the collarand toe of the trace.

If you are using a distance or point secondarytable:

Distance/Location. Select this option toposition the trace symbols at theDISTANCE/LOCATION values down the trace.

Middle. Select this option to position thetrace symbols between theDISTANCE/LOCATION values down the trace.

◊ Colour By Field Value. Check this option to vary thecolour of the trace symbols depending on a value in aspecified field. This option will override the Colourparameter. Enter the following parameters to determinethe symbol colours:

Field. From the list of available numeric ortext fields, select the name of the fieldcontaining the data you wish to use todetermine the symbol colour.

Profile. From the list of colour profilesdefined for the specified field type, select thecolour profile to which you wish to map thespecified field.

5. Click the Trace tab. Enter the following parameters:

• • Show Trace Line. Check this option to display the traceline. Enter the following parameters to specify how thetrace will be displayed:

◊ Colour. Pick the colour to be used to display the trace ofthe hole from the 16 standard Gemcom colours. If youwill be using Colour By Field Value, enter the colour

Page 2409


for those portions of the trace that have no intervaldefined or have a value of “Not Entered”.

◊ Symbol Size. Enter a size in the measurement units ofyour project (i.e., feet or metres) for the default symbolsthat appear when the drillhole crosses the active plane,or enters or exits the corridor, and for the collar and toeof the hole.

◊ Colour By Field Value. Check this option to vary thecolour of the trace line depending on a value in aspecified field. Enter the following parameters todetermine the trace line colours:

Table. Pick the name of the table thatcontains the field you wish to use todetermine the trace colour, from the list oftables available in the specified drillholeworkspace. Note that if you specify theheader table, the entire trace will be a singlecolour because the header table has only onerecord per drillhole.

Figure 15-9: Drillhole Display Profile Editor (Trace tab)

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Field. From the list of available numeric ortext fields, select the name of the fieldcontaining the data you wish to use todetermine the trace colour.

Profile. From the list of colour profilesdefined for the specified field type, select thecolour profile to which you wish to map thefield.

◊ Thick. Check this option to display the trace line as athick “core” along the drillhole trace. Use this optionwith Colour By Field Value to display interval data asthe coloured bars of this thick trace line. Enter thefollowing parameters:

Radius. Enter the desired radius for thedrillhole “core”, expressed in themeasurement units of your project (i.e., feetor metres).

Where No Field Value. If you are using acolour profile for the trace, select how youwant the trace to appear for those portionsthat have no interval defined or have a valueof “Not Entered”. Choose Draw Thin to havethe intervals drawn in the width of a regulartrace, Draw Thick to have the intervalsappear as coloured bars on the trace, or NoTrace to have actual gaps displayed.

• Show Annotation. Check this option to display annotationfor the drillhole intervals. You can use multiple fields (up to16) from multiple tables for the annotation. Multiple fieldswill be displayed in the order they are entered in the gridfrom the trace outwards. The annotation can be innumerical or text format. Annotations show the same valuesas would be found in the spreadsheet editor, includingspecial values (long memo fields may be truncated). Enterthe following parameters:

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◊ Position. Choose a position for the annotation fieldsrelative to the FROM/TO or DISTANCE or LOCATION

interval information from the table they are from. If youare displaying annotation fields from more than onetable, this position applies to all tables. Select one of thefollowing options for the location of the annotation withineach interval:


From. Select this option to position theannotation next to the trace interval FROM

values.

Middle. Select this option to position theannotation between the FROM and TO valuesof the trace intervals.

To. Select this option to position theannotation next to the trace interval TO

values.

If you are using a distance or point table:

From/To. Select either option to position theannotation at the DISTANCE/LOCATION valuesdown the trace.

Middle. Select this option to position theannotation between the DISTANCE/LOCATION

values down the trace.

◊ Tick Marks. Check this option to have the intervalsfrom the table of the innermost annotation field on eachside of the trace marked by ticks. Thus, at most, a tracecan have one set of ticks down the left side and one setdown the right. The tick mark location does not have tocorrespond to the annotation position. The tick markswill appear in the same colour as their annotation field.

Page 2412


◊ Position. Select one of the following options for thelocation of the tick marks within each interval down thetrace:


From. Select this option to position the tickmarks next to the trace interval FROM values.

Middle. Select this option to position the tickmarks between the FROM and TO values of thetrace intervals.

To. Select this option to position the tickmarks next to the trace interval TO values.

From and To. Select this option to positiona tick mark at both the FROM and TO values ofthe trace intervals. Each FROM tick mark willsimply be overlapped by a TO tick mark withthe exception of the first FROM and the lastTO. Thus, this option ensures that there willbe a tick mark both at the collar and toe ofthe trace.

If you are using a distance or point table:

From/To/From and To. Select any of theseoptions to position the tick marks at theDISTANCE/LOCATION values down the trace.

Middle. Select this option to position the tickmarks between the DISTANCE/LOCATION

values down the trace.

For each field that you want to include in the annotation,enter the following parameters in the grid editor:

◊ Table Name. Pick the name of the table containing thefield you wish to display from the list of tables availablein the specified drillhole workspace. Note that if you

Page 2413


specify the header table, information is only displayed atthe collar or toe, because the header table has only onerecord per drillhole. Select None to clear the row of anyother row entries.

◊ Field Name. Pick the name of the field you wish todisplay from the list of fields available in the selectedtable.

◊ Axis. For a coordinate field, specify whether to use theX, Y, or Z values.

◊ Colour profile. If applicable, pick the name of a colourprofile from the list of colour profiles defined for theselected field type.

◊ Position. Select one of the following options todetermine the position of the field annotation relative tothe trace. If you have selected a field from the headertable, you may choose between collar and toe as well.

Left. This option positions the annotation onthe left side of the trace. This would normallybe used with a visible trace.

Right. This option positions the annotationon the right side of the trace. This wouldnormally be used with a visible trace.

Top. This option positions the annotationabove the specified annotation position(From, Middle, or To) in each interval. This isuseful when, for example, trace symbolswithout trace lines are being displayed. Topcan also be used to position annotation at thecollar when you are displaying a field fromthe header table.

Bottom. This option positions the annotationbelow the specified annotation position(From, Middle, or To) in each interval. This is

Page 2414


useful when, for example, trace symbolswithout trace lines are being displayed.Bottom can also be used to positionannotation at the toe when you aredisplaying a field from the header table.

◊ Text Height. Enter the character height for theannotation in the measurement units of your project(i.e., feet or metres).

Pressing [Tab] at the last column of the last row entered willgenerate a new row.

6. Click Save to save your current settings. Click Exit.

Display Settings

This command allows you to specify various drillhole displaysettings. Some of these settings override values in the currentlyselected display profile. Others allow you to customize theappearance of annotation, specify how drillhole traces are renderedin Z-buffer mode, to set up distance markings, and to choose eitherto show or hide drillhole elements (e.g., trace symbols) and intersectpoints. You can also easily change the way drillhole data isdisplayed by selecting a different display profile with this commandat any time after the drillhole data has been loaded.

Note that the eight show/hide options are also available in theProperties } Views Settings dialog box (available through a rightmouse click). When the options are changed here, only the selectedworkspace is affected; Views Settings parameters affect all loadedworkspaces. Choosing not to display various elements of thedrillhole will not affect any other active drillhole information. Thedisplay of drillholes can be turned on or off completely withoutclosing the drillhole workspace or unloading the drillhole data.

The values that appear in the dialog box (other than the defaults)have been loaded from the session file and any changes made will

Page 2415


be saved back to the session file. The most recent values will beused as you load each workspace.

To define your display settings, follow these steps:

1. Select Drillhole }} Display }} Display Settings. The SelectWorkspace dialog box will appear if you have more than oneworkspace open. Specify a drillhole or traverse workspace byclicking a workspace name in the list of available workspacesand click OK.

2. In the Drillhole Display Settings dialog box, enter any of thefollowing parameters as desired:

• Display Profile. The name of the current display profilewill appear. You may specify a new current display profilefrom the profiles for the current workspace.

• Define. If necessary, this option opens the DrillholeDisplay Profile Editor, so that you can modify, add, orrefer to a display profile.

• Override Hole ID Text Height. Enter a value that willoverride the collar text height specified in the displayprofile.

• Override Annotation Text Height. Enter a value thatwill override all of the text heights for the trace annotationspecified in the display profile.

• Adjust Annotation Text Angle. Annotation text isnormally displayed perpendicular to the trace (at a 0 degreeangle). Enter a new angle for the annotation between -90and 90 degrees.

• Allow Upside-Down Text. The program normally tries todisplay annotation text “right-side-up” (relative to the top ofthe screen). Check this option to allow text to remain right-side-up relative to the top of the drillhole and thus possiblyupside-down on the screen. This may be desirable when

Page 2416


viewing drillholes that are nearly horizontal or whenrotating data onscreen.

• Number of Points for Rendering. This parameterdetermines how many points are used to define the cross-sectional profile of a drillhole core in Z-Buffer mode. Fourpoints generate a square profile, eight points an octagon,etc. Increasing the number of points will make the core lookmore cylindrical but will increase rendering time. Choose aninteger between 4 and 20.

• Override Radius. To override the radius that is specifiedin the display profile for a “thick” drillhole trace, check thisoption and enter another value. Note that a value of zerowill cause a regular “thin” trace to be drawn.

Figure 15-10: Drillhole Display Settings dialog box

Page 2417


• Display Distance Markings. Check this option tosuperimpose downhole distance information on drillholetraces. Gemcom for Windows will display tick marks andannotation of the distances down the hole from the collar onthe left side of the trace. This can be useful when viewingdrillholes to determine how far down a specific hole acertain geological feature exists (for example, a fault). It isalso useful for data validation when viewing intervalinformation.

◊ Text Height. Enter the character height for theannotation in the measuring units of your data (i.e., feetor metres).

◊ Text Colour. Select the colour for the distancemarkings from the 16 standard Gemcom colours.

◊ Decimal Places. Select the number of decimal placesfor the distance annotation (between 0 and 3 decimalplaces).

◊ Lower Depth. Specify the distance from the collar atwhich you want the markings to begin. The default(zero) places the first mark at the collar. Note that thisis not an elevation value but the beginning of a range forthe distance values.

◊ Upper Depth. Specify the distance from the collar atwhich you want the markings to end. The default(999,999) places the last mark at the toe. Note that thisis not an elevation value, but the end of a range for thedistance values.

◊ Distance Interval. Specify the distance between themarkings along the hole.

• Show Drillholes. Check this option to display thedrillholes and all associated annotation.

• Show Hole ID. Check this option to display the drillholename. Clear the option not to display the drillhole name.

Page 2418


• Show Collar Symbol. Check this option to display thedrillhole collar symbols. When this option is cleared, thedefault collar symbol, the Q_circle, appears instead for eachdrillhole (if the trace lines are being displayed).

• Show Trace Symbols. Check this option to display thetrace symbols. Clear the option not to display the tracesymbols.

• Show Trace Line. Check this option to display thedrillhole traces. Clear the option not to display the drillholetraces.

• Show Annotation. This option allows you to togglebetween displaying or not displaying the trace annotation.

• Show Intersects. Check this option to display the drillholeintersect points. Clear the option not to display the drillholeintersect points.

• Show Inactive Intersects. If the Show Intersects optionis checked, you can check this option to display inactive(unselected) drillhole intersect points.

3. Click OK to save your settings and close the dialog box. You maybe asked to confirm the loading of new data from the database,if necessary. Your active data will be updated according to thenew settings.

Page 2419


Display Intersect Information

This command allows you to display information about any selectedintersect on any drillhole.

Figure 15-11: Drillhole Intersect Information dialog box

1. Choose Drillhole }} Display }} Display Intersect Information. TheSelect Workspace dialog box will appear if you have morethan one workspace open. Specify a drillhole or traverseworkspace by clicking a workspace name in the list of availableworkspaces and click OK.

2. Use the mouse to select the intersect for which you wish to viewinformation.

3. The Drillhole Intersect Information status box will displaythe drillhole name and length, and the downhole distance,coordinates, and field values for the selected intersect. The fieldinformation is from the set of fields specified in the display andload profiles. Note that for coordinate type fields, anycoordinate information displayed as a field value is locationinformation taken from the record in the database (i.e., it is notcalculated by the program). Click OK to proceed.

4. Repeat steps 2 and 3 as desired.

Page 2420



Display Trace Information

This command allows you to display information about any selectedpoint along a drillhole. This is identical to Display IntersectInformation except that you use the mouse to snap anywherealong the trace, instead of only to intersects.

1. Choose Drillhole }} Display }} Display Drillhole Information. The SelectWorkspace dialog box will appear if you have more than oneworkspace open. Specify a drillhole or traverse workspace byclicking a workspace name in the list of available workspacesand click OK.

2. Use the mouse to select the point along a drillhole for which youwish to view information.

3. The Drillhole Intersect Information status box (see Figure15-11) will display the drillhole name and length, and thedownhole distance, coordinates, and field values for the selectedpoint on the drillhole. The field information is from the set offields specified in the display and load profiles. Note that forcoordinate type fields, any coordinate information displayed asa field value is location information taken from the record inthe database. Click OK.

4. Repeat steps 2 and 3 as desired.


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Exploration Chapter 16: Drillhole Compositing

Chapter 16

Drillhole Compositing

In this Chapter

• Introduction• Compositing Existing Workspace Data (Drillhole-only

Compositing)• Drillhole-Solid Compositing• Before You Start• Validating Intervals• Compositing Profiles• Preparing the Composite Table• Calculating Composites• Thickness Calculation• Assigning Grades to Solids from Drillholes• Updating the Workspace with Drillhole-Solid Intersections• Creating ASCII Files of Drillhole-Solid Intersections

Introduction

Compositing is the process of combining individual samples of shortlengths into longer lengths using weighted average techniques. Youcan composite data in either traverse or drillhole workspaces fromany secondary tables that have data in intervals defined with theFROM and TO format.

You can take data from as many tables as you want and create asmany tables with composite values as you want. The tables that youtake data from for calculating composite values are called sourcetables. The tables containing the calculated composite intervals and

Page 2422


values are called composite tables. You can use composite tables inexactly the same way as you use any other tables. That is, thesetables can be used for functions such as reporting, extracting,manipulating, plotting planes, and accessing other Gemcom forWindows applications.

Gemcom for Windows provides you with a set of very flexiblecompositing tools to perform two main types of compositing:

• Compositing Existing Workspace Data (Drillhole-onlycompositing).

• Drillhole-Solid Compositing.

These two types of compositing are discussed in detail onpage 2424.

Compositing Calculation

The general formula for calculating composite values is

compositeV L W Bk Lex W Bk Lim Wbk

L W Lex Limi i i i i i

i i i i

=+ +

+ +∑ ∑ ∑

∑ ∑ ∑* * * * * *

*

where

Vi Value from source fieldLi Length of source interval in compositeWi Value from weighting field (default = 1)Bk Background valueWbk Background value for weighting fieldLexi Length of explicit missing sample in compositeLimi Length of implicit missing sample in compositeä The sum of the values

Page 2423


Treatment of Data Types

You can composite all data types except the coordinate data typesand the memo data type. The various data types are treated asfollows:

• Integer. These are used directly in the compositing formula.Any decimal places determined during the calculation arerounded to the nearest integer.

• Real. These are used directly in the compositing formula.

• Double. These are used directly in the compositing formula.

• Date, Time, and Date and Time. Before compositing, datesand times are converted to their internal storage format(integer days since January 1st 1970 and seconds forwards orbackwards from 12 noon). Then they are converted back aftercompositing.

• Angle. These are treated the same way as real data types.

• String. The source record that has the longest interval within thecomposite interval will be directly transferred to the compositefield. If the source field is longer than the composite field, thecharacter string will be truncated to fit the composite field.

Treatment of Special Values

The special values that denote Below Detection Limit and AboveDetection Limit are treated as the workspace minimum value andthe workspace maximum value respectively. These are theminimum and maximum values that you defined when you firstcreated the workspace.

Page 2424


Compositing Existing Workspace Data(Drillhole-only compositing)

This is the process of combining samples from one or more sourcetables into a composite table. The process is divided into four mainsteps:

1. Validating intervals. Gemcom for Windows checks intervalsin the secondary table being composited for correctness.

2. Defining a compositing profile. This allows you to define theparameters for a given compositing process.

3. Creating composite intervals. Gemcom for Windowsprovides eight methods for defining the composite Forms andTos from workspace data. This step initializes the compositetable with the interval lengths but does not calculate thecomposite values.

You may want to validate your intervals again at this point toensure that the composite intervals you have created arecorrect.

4. Calculating composite values. This is a separate step thatlets you take data from more than one source table to calculatethe composite values. You can calculate composites in a singlepass through this function, or you can make multiple passesthrough the function.

Drillhole-Solid Compositing

Gemcom for Windows also allows you to perform a specific methodof compositing where composite limits (FROM-TO downholedistances) are based on the entry and exit point of drillhole tracesthrough solids and surfaces.

The program calculates the intersection of each drillhole with thesolid(s) or surface(s) and allows you to save the results to user-

Page 2425


specified fields of a workspace (or to an ASCII file). In general, theentire drillhole length inside each solid will be composited into oneinterval. The program will save the FROM values (the downholedistance to the entry point into a solid) and the TO values (thedownhole distance to the exit point from a solid). Each new intervalcan then be assigned a composite value.

The main functions of this type of compositing include thefollowing:

• Assigning grade values to solids based on length-weighteddrillhole assays or composites.

• Calculating intersections of solids/surfaces with drillhole tracesand storing the FROMs, TOs, or distances either back to aGemcom drillhole workspace or in an ASCII file.

In practice, these tools may be used in the following situations:

• Drillhole grade data may provide an alternative estimate (or auseful check) of a solid’s grade. It may also be used in thepreliminary stages of project evaluation to quickly estimate anin-situ resource (just as the polygonal resource method may beused when modelling 2D planes).

• If no rock type information was logged and stored in aworkspace table, the solid intersections can be used to populatea rock type field in a workspace table.

• It may be necessary to constrain drillhole compositingoperations within certain domains (for example, within certainrock types or mineralized zones). By intersecting drillholes withsolids, these domains (the actual drillhole length inside thedomain) can be automatically calculated and the workspaceupdated with this new information.

• In cases where Gemcom for Windows is used for undergroundmine planning, drillhole-solid compositing may be used forvisual inspection of the relationships between drillholes andother objects (such as stopes), and for calculating exact points of

Page 2426


intersection (for example, where a drillhole may pass though anaccess tunnel).

The process is divided into the following six steps, some of whichare optional:

1. Validating intervals. Gemcom for Windows checks intervalsin the secondary table being composited for correctness.

2. Defining a compositing profile. This allows you to define theparameters for a given compositing process.

3. Updating the workspace with drillhole-solidintersections. This step initializes the composite table withthe interval lengths calculated from the intersection of thedrillholes with a selected solid or surface, but does not calculatethe composite values.

You may want to validate your intervals again at this point toensure that the composite intervals you have created arecorrect.

4. Thickness Calculation. This menu command allows you tocalculate true, horizontal and vertical thicknesses. Thiscalculation can be used as a weighting factor in the compositetable.

5. Calculating composite values. This is a separate step thatlets you take data from more than one source table to calculatethe composite values. You can calculate composites in a singlepass through this function, or you can make multiple passesthrough the function.

6. Assigning grades to solids. This step assigns grades to solidsfrom drillhole data stored in the composite or assay tables.

If you want to create composite intervals from drillhole-solidintersections, but do not want to update the composite table in theworkspace, you can use the Create ASCII File of Drillhole/SolidIntersections command to store the drillhole-solid compositeinformation in an ASCII file instead.

Page 2427


Before You Start

Before you calculate any composite values, you must make surethat your workspace structure is suitable. The structure mustcontain the following key elements in order to be able to calculateand store composites:

• The minimum drillhole or traverse workspace structure mustbe present. These are defined in Chapter 3: The Gemcom forWindows Workspace.

• The table that you want to store the composites in must haveFROM and TO fields.

• The composite table must have a field called COMP-ID with astring (character) data type and a length of at least 10characters. This field is filled when the composite intervals arecreated. For plane composites, the plan view name is writteninto this field. For all other types of composites, a compositesequence number is written into the field.

• Fields in the composite table must have appropriate data typesfor the values to be composited.

• You should also have a field in the composite table to store thecalculated composite length. This field is optional and you canname it whatever you want. It should have a real or double datatype. Note that the composite length can only be calculatedduring the compositing process and is not necessarily the sameas the total length of the composite interval, depending on themethod selected.

In order to perform drillhole-solid compositing, there are a numberof additional requirements that must be met:

• If you plan to update your workspace with the FROM-TO (and,optionally, rock type) information resulting from thedrillhole/solid intersection process, you must make sure thereare fields allocated within the workspace table structure tostore this information. If these fields were not defined when the

Page 2428


workspace structure was created, you will need to add them (seeChapter 4, Creating and Modifying Workspace Structures).

• You must have prepared a drillhole loading profile thatspecifies which elements will be used for the drillholecompositing. You must also have defined a drillhole displayprofile for the drillhole data. As well, you should create loadingand display profiles that will be suitable for viewing the newcomposite data after creating it.

• You must have defined rock codes and grade elements for yourproject (see Chapter 6: General Data Definitions, Volume I:Core for more information).

• You must have created one or more solid or surface that will beused for the drillhole-solid intersection calculation.

Drillhole Workspace

The Drillhole Compositing submenu uses the current workspacethat is assigned under the Workspace menu, except for thecommands Assign Grades to Solids from Drillholes andUpdate Workspace with Drillhole/Solid Intersections. Thesecommands use the drillhole data currently loaded in the Drillholemenu. If multiple workspaces are open, these commands operate asthough all workspaces are simultaneously selected.

Validating Intervals

Before you try to calculate any composites from a workspace, youshould validate the intervals in the source tables that you intend touse. Validating these tables will check for the following possibleproblems:

• Any intervals that have a length less than or equal to zero. (Thelength is the value in the TO field minus the value in the FROM

field.)

Page 2429


• Any interval that is out of sequence. This occurs when the valuein the FROM or the TO field is less than the corresponding valuein the previous record.

• Any portion of the hole that does not have an interval defined.

The validation process will produce a record by record report of allinconsistencies. The report may be directed to the screen, to theprinter or to a text file.

The validation process will not try to correct any inconsistencies.You will either have to manually edit the workspace to fix any zeroor negative length intervals, or sort the source table to fix any outof sequence intervals.

To validate your data prior to preparing composite intervals, selectWorkspace }} Validate Data }} Validate Drillhole Data. For moreinformation on data validation, see Chapter 8: Validating Data.

Compositing Profiles

Before you can composite any data, you will have to define acompositing profile. A compositing profile stores the compositingparameters, the source table and field names, the target compositefields names, the weighting method, and treatment of missingsamples. Each profile is given a name, and you can define as manyprofiles as you want. When you want to calculate some compositevalues, you select the profile that you want to use from a list or byentering its name.

Follow this procedure to define a compositing profile:

1. Select Drillhole }} Drillhole Compositing }} Define Compositing Profiles.The Composite Profile Editor dialog box will appear (seeFigure 16-1).

2. Click Add and type in a name for your profile. Click OK.

!

Page 2430



• Description. Enter a brief description of the compositingprofile, if desired.

• Composite Table. Select the target table that will containthe field for calculated length and composites.

• Field for Calculated Length. Select the target field forthe calculated composite length. The calculated length isdetermined by the sum of the lengths of all acceptedintervals in the source table that you define. This may ormay not be equal to the total length of the compositeinterval, depending on the number of missing samples inthe source table.

• Threshold length for acceptance. You can set athreshold value on the calculated composite lengths as apercentage of the total composite length. If the calculatedlength of a composite is less than this threshold, you canoptionally delete the composite interval from the compositetable.

Figure 16-1: Composite Profile Editor dialog box

Page 2431


• Delete composites shorter than threshold. If thisoption is selected, calculated lengths shorter than thethreshold specified above will be automatically deleted fromthe composite table. If it is not selected, the Thresholdlength for acceptance parameter is ignored.

• Use background value for explicit missing samples. Anexplicit missing value is a value for which the interval in thesource table is defined by values in the FROM and TO fields (inother words, there is a record present in the source table for theinterval); however, there is no value present in the source field.This will be indicated by a special entry: Not Entered, NotSamples, Insufficient Sample, Not Calculated, or Error.

If this option is selected, the background value specified for thefield will be substituted for the missing special value and thelength of the interval will be obtained from the values in theFROM and TO fields. If the option is not selected, the compositewill be calculated without using the missing sample.

• Use background value for implicit missing samples.An implicit missing sample is one for which the interval (inother words, the record) does not exist in the source table.

If this option is selected, the background value defined forthe field will be used, together with the calculated length ofthe missing record. This length is defined by the distancebetween the end of the preceding record and the start of thefollowing record. If the option is not selected, the compositewill be calculated without using the missing sample.

• Composite Parameters. For each field that contains datayou wish to composite, enter the following parameters, asapplicable:

◊ Destination Field. Select the name of the target fieldfor the composite data. Destination fields must have thesame data type as source fields.

Page 2432


◊ Source Table. Select the name of the table containingthe field from which the data to be composited will betaken.

◊ Source Field. Select the name of the field containingthe data to be composited. Source fields must have thesame data type as destination fields.

◊ Source Background. Enter a background value to besubstituted for missing values, if desired.

◊ Weighting Field. The standard weighting factor is thelength of the original sample interval. However, anothermethod of weighting is to multiply the length of theoriginal sample by a value found in another field(thickness calculation or specific gravity, for example) inthe same source table. This value is known as theweighting factor.

Select the name of the field that contains the weightingfactor, if you are using one.

◊ Weighting Background. Enter a value to use if thevalue in the weighting field is missing. If no extraweighting is required, then the default value forweighting is set to 1.

4. Click Save to save your profile definition. Click Exit.

Preparing the Composite Table

The composite table holds the calculated intervals which will beused to calculate the actual composite values. This applicationprepares the composite table for composite calculations performedusing data from an existing workspace table.

You can define the composite intervals along the length of thedrillholes using any of the following eight methods:

Page 2433


• By plan view. The composite intervals are determined fromthe intersection of the drillhole or traverse with plan views.

• By equal length. You can define a constant length that will beused for each composite.

• By length within intervals from another table. Thismethod combines the intervals from another table with thelength method. Composite intervals are first determined bydirectly transferring the intervals from any other table ininterval format. The intervals are then subdivided further intointervals of constant length, starting either at the beginning orthe end of the previously defined intervals.

• By intervals from another table. The composite intervalsare determined by directly transferring the intervals from anyother table in the workspace that is in interval format.

• By merging intervals from two tables. The compositeintervals are created by combining the FROM and TO fields fromtwo source tables.

• By a single cut-off value. The composite intervals are obtainedfrom combined intervals (in a source table) whose values (in aselected field) are greater than a specified cut-off value.

• By multiple cut-off values. The composite intervals are createdbased on two cut-off values (waste and ore-waste) and a strip ratio.The waste cut-off value determines the initial waste layer. The ore-waste cut-off value determines the subsequent ore and wastelayers.

• By grouped similar values. The composite intervals arecreated by grouping records that contain similar consecutivevalues to form new FROM and TO intervals. The grouping fieldscan be either numeric or string formats.

The command you select to prepare the composite table willnormally depend on the morphology of your ore body, and the typeof resource calculation that is ultimately required.

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Follow these steps:

1. Select Drillhole }} Drillhole Compositing }} Prepare Composite Table.

2. The Select Records to Process dialog box will appear. Selectthe option you wish to use as outlined in Chapter 4: DialogBoxes, Volume I: Core.

3. From the list that appears, select the table that is to hold thecomposite intervals. Note that this table must contain thefollowing fields:

• COMP-ID• FROM

• TO

If this table already has data in it, you will be asked if you wishto overwrite this data. Select Yes to overwrite; select No to exitfrom the composite table preparation process.

4. Select a method to be used for creating the composite intervalsand enter any parameters required by the selected method.There are eight methods available:

• Plan Views• Equal Length• Length Within Intervals from Another Table• Intervals from Another Table• Merging Intervals from Two Tables• Single Cut-Off Value• Multiple Cut-off Values• Grouped Similar Values

These eight options and the additional parameters they requireare discussed in detail below.

5. When you have entered all parameters as required, click OK.The Compositing status window will appear, displaying theprogress of the composite interval creation process. This processmay take some time. When the process is complete, click OK.

Page 2435


Creating Composites by Plan View

You can create composites that have lengths determined by theintersection of the drillhole or traverse with plan views.

Each plan view definition contains the reference elevation of the planview and the thickness of the plane (defined by the upper and lowerelevation limits). These parameters define a projection corridor that isbounded by two parallel faces at the upper and lower elevation limits.

The plan views are sorted into descending (highest to lowest) orderbefore defining the composite intervals. This ensures thatcomposites are defined in the correct order.

Composite intervals are defined by the intersection of the drillholeor traverse with the projection corridor. The value in the FROM fieldis determined by the intersection of the drillhole or traverse as itenters the corridor. The value in the TO field is determined by theintersection of the drillhole or traverse as it exits the corridor.

Figure 16-2: Composites by plan views

Page 2436


To create composite intervals by plan view, follow these steps:

1. Complete steps 1 to 3 in “Preparing the Composite Table” onpage 2432.

2. The dialog box entitled Method for Creating CompositeIntervals will appear. Select Plan View and click OK.

3. Select the desired plan view(s) from the list that appears andclick OK.

4. The Composite by Horizontal Plan View status window willappear, displaying the progress of the composite tablepreparation process. When the process is complete, the statuswindow will disappear from the screen. You can cancel theprocess at any time by clicking Cancel.

Gemcom for Windows does not check to see whether the planecorridors have gaps between them. If you use planes to definecomposite intervals, make sure you validate the values in the FROM

and TO fields in the composite table after you calculate thecomposite intervals. This will report any overlaps, missingcomposites, out of order composites, etc.

Creating Composites by Equal Length

You can create composites that all have the same length. Thecomposite intervals are determined by one of two methods:

• Starting at the collar of the drillhole or traverse and increasingthe values by equal increments in the FROM and TO fields insuccessive records in the composite table. The length of theincrement equals the composite length (see Figure 16-3).

• Starting at the toe of the drillhole or traverse and reducing thevalues in the FROM and TO fields by equal increments (seeFigure 16-4).

To create composite intervals by length, follow these steps:

!

Page 2437



Figure 16-3: Composites by length—starting at collar

Figure 16-4: Composites by length—starting at toe

Page 2438


2. The Method for Creating Composite Intervals dialog boxwill appear. Select Equal Length and click OK.

3. The Composite by Equal Length dialog box will appear.Enter the following parameters:

• Table for Compositing. This parameter is filled in for youdepending on the table you selected in step 1. You cannotchange it in this dialog box.

• Compositing Length. Enter the desired length for yourcomposited intervals.

• Starting Position. Select one of the two following choices.

◊ Start from Collar. See Figure 16-3.

◊ Start from Toe. See Figure 16-4.

4. Click OK to accept your parameters and close the dialog box.

5. The Composite by Equal Length status window will appear,displaying the progress of the composite table preparationprocess. When the process is complete, the status window willdisappear from the screen. You can cancel the process at anytime by clicking Cancel.

Because the total length of the drillhole or traverse is not an exactmultiple of the composite length, there often is a short compositelength left over. This residual length will be positioned either at thecollar or the toe of the drillhole or traverse, depending on thedirection selected.

Creating Composites by Length Within Intervals from AnotherTable

You can create composite intervals using a combination of intervalsfrom another table and constant lengths. The intervals in thecomposite table are first created by directly transferring valuesfrom the FROM and TO fields in the source table. Each of these

Page 2439


intervals are then subdivided into equal lengths, beginning eitherat the start of the interval and progressing down the drillhole ortraverse, or beginning at the end of the interval and progressingback along the drillhole or traverse towards the collar.

To create composite intervals by using a combination of constantlengths and intervals from another table, follow these steps:


2. The Method for Creating Composite Intervals dialog boxwill appear. Select Length Within Intervals from Another Table andclick OK.

3. The Composite by Length Within Intervals from AnotherTable dialog box will appear. Enter the following parameters:

Collar of hole

Source tableintervals

Intervals used todefine initialcomposites

Toe of hole

Composite intervalswith equal length

Residual compositeintervals

Residual compositeinterval

= 5 ft

Figure 16-5: Composites by length within intervalsfrom another table

Page 2440



• Controlling Table. Select the table which contains thelengths that you wish to use in the compositing process.

• Compositing Length. Enter the length that you want yourcomposited intervals to be.

• Starting Position. Select one of the two following choices.

◊ Start from Collar. See Figure 16-3.

◊ Start from Toe. See Figure 16-4.

4. Click OK to accept your parameters and close the dialog box.

5. The Composite by Length Within Intervals from AnotherTable status window will appear, displaying the progress of thecomposite table preparation process. When the process iscomplete, the status window will disappear from the screen.You can cancel the process at any time by clicking Cancel.

As the intervals from the source table will not usually be an exactmultiple of the composite length, there will be a short residualcomposite left either at the end or the start of the interval.

Creating Composites by Intervals from Another Table

You can create composite intervals by directly transferring thevalues in the source table FROM and TO fields into the compositetable FROM and TO fields.

To create composite intervals by using intervals from another table,follow these steps:


Page 2441


2. The Method for Creating Composite Intervals dialog boxwill appear. Select Intervals from Another Table and click OK.

3. From the Select Table with Intervals dialog box thatappears, select the table which contains the FROM and TO fieldsyou wish to use and click OK.

4. The Composite by Intervals from Another Table statuswindow will appear, displaying the progress of the compositetable preparation process. When the process is complete, thestatus window will disappear from the screen. You can cancelthe process at any time by clicking Cancel.

Figure 16-6: Composites by interval from another table

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Creating Composites by Merging Intervals from Two Tables

This method allows you to create composite intervals by combiningintervals from two source tables. In addition, you can suppressintervals in the first source table by specifying a matching string(to be matched to the contents of a field in the first source table) toselect the intervals to be suppressed.

To create composite intervals by merging intervals from two tables,follow these steps:


2. The Method for Creating Composite Intervals dialog boxwill appear. Select Merging Intervals from Two Tables and click OK.

3. The Composite by Merging Intervals from Two Tablesdialog box will appear. Enter the following parameters:

Figure 16-7: Composites by merging intervalsfrom two tables

Page 2443



• First Source Table. Select the name of the first tablecontaining the intervals to be merged.

• ID Field from First Source Table. Select the name of thefield that contains an identifier string to be used to suppressrecords.

• Matching String for Record Suppression. Enter a textstring (maximum 10 characters) that identifies intervals tobe suppressed. You can use the wildcard characters * and ?.

• Second Source Table. Select the name of the second tablecontaining the intervals to be merged.

• ID Field from Second Source Table. Select the field fromthe second table that contains an identifier string. Thecontents of this field are concatenated (added) to thecontents of the ID field in the first source table, and theresulting string is placed in the COMP-ID field in thecomposite table. You must make sure that when you definethe COMP-ID field, it is long enough to contain the contents ofboth ID fields. For example, if the contents of the ID field inthe first source table is WASTE and the contents of the ID

Figure 16-8: Composite by Merging Intervalsfrom Two Tables dialog box

Page 2444


field in the second source table is 4950, then the contents ofthe new COMP-ID field would be WASTE-4950.

4. Click OK to accept your settings. The Composite by MergingIntervals from Two Tables status window will appear,displaying the progress of the composite table preparationprocess. When the process is complete, the status window willdisappear from the screen. You can cancel the process at anytime by clicking Cancel.

Creating Composites by Single Cut-off Value

You can define composite lengths based on the intervals (in thesource table) that have values (in a selected field) greater than orequal to a specified cut-off value.

The start of the first composite field is determined by the start ofthe first interval in the source table that has a value in a selectedfield greater than or equal to the cut-off value. The end of the firstcomposite field is determined by the start of the next consecutiveinterval that has a value in the selected field that is less than thecut-off value. This is repeated for all occurrences of values in theselected field greater than or equal to the cut-off value.

Thus, each composite interval is made up of a series of consecutiveintervals from the source table with values greater than or equal tothe cut-off value.

You can modify this process slightly by applying two constraints:

• Minimum composite length. If the resultant composite length isless than a defined minimum length, the composite will not beaccepted. This option ensures that very short high valuesamples which are separated by long intervals that are belowcut-off do not create many short composites (see Figure 16-10).

• Maximum inclusion length. If the total length of a series ofunaccepted intervals in the source table is less than thismaximum inclusion length, and there is an accepted interval

Page 2445


before and after this unaccepted series, the unaccepted lengthwill be included in the composite interval (see Figure 16-11).

Collar of hole No composite

Composite

No composite

No composite

Composite


Toe of hole

Values in sourcetable data field

≥≥ Cut-off

Figure 16-9: Composites by single cut-off values

To create composite intervals by using a cut-off value, follow thesesteps:


2. The dialog box entitled Method for Creating CompositeIntervals will appear. Select Single Cut-off Value and click OK.

3. The Composite by Single Cut-off Value dialog box willappear. Enter the following parameters:


• Controlling Table. Select the table which contains thefield you wish to use to control the compositing process.

Page 2446


Collar of hole

Interval <8 ft longso not composited

Composite

Composite

Composite


(eg. all 5 ft long)

Toe of hole


≥≥ Cut-off

Minimum composite length = 8 ft

Figure 16-10: Effect of minimum composite length

Collar of hole

Interval <8 ft longso included intocomposite

Composite

Composite


(eg. all 5 ft long)

Toe of hole


≥≥ Cut-off

Maximum inclusion length = 8 ft

Figure 16-11: Effect of maximum inclusion length

Page 2447


• Cut-Off Field. Select the field you wish to use to controlthe compositing process.

• Cut-Off Value. Select the value to use to create thecomposite intervals.

• Max Inclusion Length. Enter a maximum length for non-composited intervals (i.e., intervals for which the data in thecut-off field is lower than the cut-off value) to be included incomposited intervals on either side (see Figure 16-11).

• Min Composite Length. Enter a minimum length forcomposite intervals. Intervals shorter than this length willnot be accepted (see Figure 16-10).

4. Click OK to accept your settings The Composite by SingleCut-Off Value status window will appear, displaying theprogress of the composite table preparation process. When theprocess is complete, the status window will disappear. You cancancel the process at any time by clicking Cancel.

Composites that are defined by cut-off will not expand the compositeinterval to include below cut-off intervals above or below thecomposite interval. If you want to do this type of compositing,please refer to Gemcom's ONE-D Compositing Optimizer. This utilityhas been specifically designed for this purpose. Contact Gemcomfor further details.

Creating Composites byMultiple Cut-off Values

This method allows you to create a maximum of three composites in adrillhole. These composites represent layers of ore or waste. If youcreate three composites, the top and bottom layers will represent wastelayers. The following summarizes all the possible combinations of oreand waste that can be created from one, two and three composites:

• One composite layer. Either a waste layer or an ore layer.

!

Page 2448


• Two composite layers. Either a top waste layer and bottomore layer, or a top ore layer and bottom waste layer.

• Three composite layers. A top waste layer, middle ore layer,and bottom waste layer.

This compositing method is an iterative method and works asfollows:

1. Normal composites by cut-off are calculated down each hole.The composites will either be waste (all consecutive intervalsare less than the waste cut-off); sub-cut-off (all consecutiveintervals are greater than the waste cut-off and less than theore cut-off); and ore (all consecutive intervals are greater thanthe ore cut-off).

2. Starting at the top of the first ore composite, consecutive pairsof composites are examined to determine

• if their combined value is greater than the ore cut-off,

• if the ratio of their lengths is greater than the ore/wastestrip ratio, and

• if the waste interval length is less than the specifiedmaximum.

If the above conditions are true, then the two intervals arecombined into an ore composite. If any of the conditions fail,then the two are combined into a waste interval.

3. The process is then repeated, starting at the top of the next orecomposite.

Because the waste strip and ore-waste cut-off values can bedifferent, there is a possible sub-cut-off zone between the top wastelayer and the ore layer. If this happens, the sub-cut-off zone will beconsidered as either part of the waste layer or the ore layerdepending on the circumstances. The diagrams in Figure 16-12show how the sub-cut-off zone is being treated in different cases.(These diagrams only show the top part of the hole.)

Page 2449


In Case 1, the sub-cut-off zone is accumulated as part of the wastezone for further evaluation with subsequent layers down the hole.If there is no ore zone detected, the sub-cut-off zone will beconsidered as waste.

All samples belowwaste cut-off


All samples abovewaste cut-off butbelow ore cut-off

Waste composite

Waste composite

Sub cut-off zone

Case 1

All samples above orecut-off and ratio oflength to length of

sub cut-off is abovestrip ratio


Ore composite

Sub cut-off zone

Case 2

All samples above orecut-off and ratio oflength to length ofwaste composite is

above strip ratio



Ore composite

Waste composite

Sub cut-off zone

Case 3

All samples above orecut-off and ratio oflength to length ofwaste composite is

above strip ratio



Ore composite

Waste composite

Sub cut-off zone

Case 4

Figure 16-12: Compositing by Multiple Cut-Off case studies

Page 2450


In Case 2, the sub-cut-off zone is initially evaluated as waste. If thiscondition fails, then the sub-cut-off zone is accumulated as wastefor further evaluation with subsequent layers down the hole.Otherwise, the sub-cut-off zone will become ore.

In Case 3, the sub-cut-off zone is accumulated as part of the wastezone for further evaluation with the subsequent layers down thehole.

In Case 4, a two-step evaluation process is applied. The sub-cut-offand ore zones are first evaluated with the sub-cut-off zone beingtreated as waste. If this condition passes, a second evaluation isapplied with the sub-cut-off zone being treated as ore. If either ofthe above two checks fail, then the sub-cut-off zone is accumulatedas part of the ore layer for further evaluation with the subsequentlayers down the hole.

To create composite intervals by using multiple cut-off values,follow these steps:


2. The Method for Creating Composite Intervals dialog boxwill appear. Select Multiple Cut-off Values and click OK.

3. The Composite by Multiple Cut-off Values dialog box willappear. Enter the following parameters:


• Above Cut-Off Length Field. Select the field to be used tostore the length of the interval that is above the ore-wastecut-off. If this field is left blank, there will be no lengthcalculation.


Page 2451


• Cut-Off Field. Select the field name of the assay that isused for cut-off determination.

• Waste strip Cut-Off Value. Enter a value to use as a cut-off to determine the top waste strip layer.

• Ore-Waste Cut-Off value. Enter a value to use as the cut-off value for separating ore and waste layer.

• Ore-Waste Ratio (LW/LO). Enter the strip ratio (i.e., thelength of waste as compared to the length of ore).

• Multiple WASTE/ORE Layers. Select one of the followingtwo options:

◊ Yes. Select this option if there will be more than onewaste/ore couplet.

◊ No. Select this option if there is only one waste/orecouplet.

Figure 16-13: Composite by Multiple Cut-Off Values dialog box

Page 2452


• Cut-Off Check on 1st Couplet. Select one of the followingtwo options:

◊ Yes. Select this option to check whether the first coupletis above the ore/waste cut-off value.

◊ No. Select this option not to check whether the firstcouplet is above the ore/waste cut-off value.

• Maximum Waste Inclusion Length. Waste intervalsshorter than the length entered here will be considered forpossible combination with an ore layer.

• Waste Composite Identifier. Enter a name of up to 10characters to identify waste composites.

• Ore Composite Identifier. Enter a name of up to 10characters to identify ore composites.

4. Click OK. The Composite by Multiple Cut-off value statuswindow will appear, displaying the progress of the compositetable preparation process. When the process is complete, thestatus window will disappear from the screen. You can cancelthe process at any time by clicking Cancel.

Creating Composites by Grouping Similar Values

You can define composite lengths by grouping consecutive recordsthat contain values of the same kind to form new FROM and TO

intervals. The grouping field can be a numeric field or a string field.

To create composite intervals by grouping similar values, followthese steps:


2. The Method for Creating Composite Intervals dialog boxwill appear. Select Grouped Similar Values and click OK.

Page 2453


3. The Composite by Grouped Similar Values dialog box willappear. Enter the following parameters:

• Table for Composites. This parameter is filled in for youdepending on the table you selected in step 1. You cannotchange it in this dialog box.

• Field to group values by. Select the field in the compositingtable in which composited intervals will be stored.


• Grouping Field. Select the field from the controlling tablewhich contains the values you wish to use to determine thenew intervals.

4. Click OK. The Composite by Grouped Field Value statuswindow will appear, displaying the progress of the compositetable preparation process. When the process is complete, the

Figure 16-14: Composites by grouping similar values

Page 2454


status window will disappear from the screen. You can cancelthe process at any time by clicking Cancel.

Updating the Workspace with Drillhole-SolidIntersections

This process performs a specific method of compositing wherecomposite limits (FROM-TO downhole distances) are based on theentry and exit points of drillhole traces through solids. Theprogram calculates the intersection of each drillhole with thesolid(s) and allows you to save the results to user-specified fields ofa Gemcom workspace. The program will save the following fields:

• FROM (downhole distance to the entry point into a solid). Thesevalues are automatically saved by the program.

• TO (downhole distance to the exit point from a solid). Thesevalues are automatically saved by the program.

• Solid names 1, 2, and 3. This is an optional field for reference.

• Solid rock code (string value). This is only available if theintersected solid is geology class. It is an optional field forreference.

• PC-MINE rock code (integer value). This is an optional field forthose who will be using PC-MINE for future grade interpolation.These codes will be used for assigning values to compositeintervals in PC-MINE. This option is only available if theintersected solid is geology class.

Note: For each of the above optional fields, you must specify whichfield within the Gemcom for Windows project will be used to storethe information. It is therefore necessary to have defined theworkspace structure to accommodate this data.

This command uses the workspace assigned under the Drillholemenu, when loading data. For this command you can have more

Page 2455


than one workspace open at a time; the program will treat them asif simultaneously selected.

Use the following procedure:

1. Select Solid }} Data }} Select Solids from List or Surface }} Data }} SelectSurfaces from List to activate the solids or surfaces that you wantto intersect with drillholes.

2. Select Drillhole }} Data }} Load Drillholes to load the drillholes thatwill be used for the solid/drillhole intersection calculations. TheSelect Workspace dialog box will appear. Specify a drillhole ortraverse workspace by clicking a workspace name in the list ofavailable workspaces and click OK.

3. Specify the desired drillhole loading profile, drillhole displayprofile, and workspace records. If the two profiles contain thefields that will be updated by the solid-drillhole intersections,the program can automatically update the drillholes in memoryfor viewing.

4. Select Drillhole }} Drillhole Compositing }} Update Workspace withDrillhole/Solid Intersections.

5. In the dialog box that appears, you must enter the followinginformation that will be stored for each interval:

• Table for Intersects. Select the table that contains thecompositing information that you wish to update with thesolid/drillhole intersection data. Note that existing recordsin the selected table will be destroyed (unless you select theheader table).

• Fields for Solid Names. Specify the fields that will beused to store the desired processing information. If you don’twant to save a particular field (e.g., Solid Name 3), leave thecorresponding data entry field blank.

• Fields for Rock type. Specify the field that will be used tostore the desired processing information. If you don’t wantto save this field, leave the data entry field blank.

Page 2456


• Field for PC-MINE Code. Specify the field to be used by PC-MINE for grade interpolation, if desired and available.

• Fields for Elements. Specify the fields that will be used tostore the desired processing information. If you don’t wantto save a particular field, leave the corresponding data entryfield blank.

6. Enter a name for an error file. The default path name will bevisible. Any significant processing errors will be described in thisfile.

7. An on-screen summary will present the number of drillholesprocessed, intervals found, overlaps found, and the name of theerror file. The drillhole information will then be updated in theworkspace.

8. After the workspace update is completed, you may refresh thescreen to see the results of the calculations.

If the selected drillhole loading profile doesn’t contain the tablethat was updated or if the selected display profile doesn’tcontain the fields that were updated, the program will ask ifyou want to reload the drillholes from the database so that youcan see the results of the calculations. If you specify Y (yes), youmust select an appropriate drillhole loading profile and drillholedisplay profile from the lists provided. The program will thenaccess the workspace so the drillholes in memory will beupdated. This is a convenient “shortcut”, equivalent tounloading the drillholes, reloading them using a differentloading profile, and reselecting the display profile.

9. View the updated table, if desired, in the Workspace Editor (seeChapter 5: Editing Data).

Page 2457


Calculating Composites

Once you have created the composite intervals in the compositetable you can calculate the actual composite values. Each compositevalue can come from a separate source table and can be calculatedusing an individual weighting method and treatment of missingsamples. You can composite up to twenty-five separate fields in asingle pass, and you can make as many passes as you want.

Updating the Composite Table

When you calculate composites, only the fields that have beendefined in the compositing profile are updated.

Follow this procedure to calculate composite values:

1. Choose Drillhole }} Drillhole Compositing }} Calculate Composites.

2. From the Select Compositing Profile list that appears,choose the compositing profile you wish to use.

3. The Select Records to Process dialog box will appear. Selectthe option you wish to use as outlined in Chapter 4: DialogBoxes, Volume I: Core.

4. The Composite Calculation status window will appear,displaying the progress of the calculation process. When theprocess is complete, the status window will disappear from thescreen. You can cancel the process at any time by clicking Cancel.

Thickness Calculation

You can use this command to calculate true, horizontal, andvertical thicknesses based on a specified strike and dip angle.Thickness calculations can be performed on drillhole or traverseworkspaces. The calculations are based on an average planarsurface that is located relative to an interval of a drillhole or a

Page 2458


traverse. The orientation of this plane is defined by the averagestrike and dip angle. The true, horizontal and vertical thicknessesare calculated for selected intervals in a drillhole or traverseworkspace by computing the angle differences between the drillholeinterval and the average dip and strike angles.

Follow this procedure to calculate thickness:

1. Select Drillhole }} Drillhole Compositing }} Thickness Calculation. TheComposite Thickness Calculation dialog box will appear.Enter the following parameters:

• Table Name. Select the name of the table which containsthe target field for the calculated thickness.

• Field for calculated thickness. Select the name of thefield which into which the calculated thickness will beinserted.

Figure 16-15: True, horizontal and vertical thicknesses

Page 2459


• Strike/Angle of Deposit. Enter the strike angle of thedeposit (see Figure 16-15).

• Dip Angle Deposit. Enter the dip angle of the deposit (seeFigure 16-15).

• Calculation Method. Select one of the three followingmethods. The figure above illustrates each of these methods.

◊ True Thickness. This is the thickness of the deposit asmeasured along a plane perpendicular to the deposit.

◊ Horizontal Thickness. This is the thickness of thedeposit as measured along the horizontal plane.

◊ Vertical Thickness. This is the thickness of the depositas measured along the vertical plane.

2. Click OK.

Assigning Grades to Solids from Drillholes

This command allows you to assign one or more grades to activegeology class solids based on length weighted intervals of alldrillholes that pass through each solid. These grade values can beused as an alternative to block models when solid grades arerequired for reserves reporting.

In Figure 16-16, the length-weighted grades of all intervals insidethe solid are used to calculate a grade for the entire solid.

In Figure 16-17, no background value is used, so the missing assaysof the drillhole inside the solid are ignored.

In Figure 16-18, missing assay lengths and background values areincluded in the solid grade calculation, effectively reducing it from6.0 to 3.86.

Page 2460


X

ZDH1 DH2

Geology solidintersected bytwo drillholes

Drillholes withassay values

6

16

14

4

9

5

11

18

13

Surface

Figure 16-16: Sectional view of drillholes intersecting a geology solid

ZDH1

Entry point

Exit point

48

Gradevalues

10m assayintervals

Solid grade =

(8x10) + (4x10)10+10= 6.0

X

Figure 16-17: Sectional view of geological solid intersected by asingle drillhole

Page 2461


X

ZDH1

48

Gradevalues

10m assayintervals

Assumingbackgroundvalue of 1,

solid grade =

(1x7)+(8x10)+(4x10)+(1x8)7+10+10+8

= 3.68

8m segmentwith no assay

7m segmentwith no assay

Figure 16-18: Sectional view of the same solid and drillhole wherethe background option is used

This command uses the workspace assigned under the Drillholemenu, when loading data. Note that you can have more than oneworkspace open at a time for this command; the program will treatthem as if simultaneously selected.

The procedure is as follows:

1. Select Solid }} Data }} Select Solids from List to activate the geologyclass solids for which you wish to assign grades.

2. Choose Drillhole }} Data }} Load Drillholes to load the drillholescontaining the assay or composite values that will be used forthe solid grade calculation. The Select Workspace dialog boxwill appear. Specify a drillhole or traverse workspace by clickinga workspace name in the list of available workspaces and clickOK.

3. Specify the desired drillhole loading profile, drillhole displayprofile, and workspace records.

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4. Select Drillhole }} Drillhole Compositing }} Assign Grades to Solidsfrom Drillholes.

5. From the list that appears, select the table that contains thegrade value fields. This table must be included in the currentdrillhole loading profile as previously defined under theDrillhole menu; the application uses the drillholes in memoryfor this process.

6. In the dialog box that appears, enter the following information:

• Use Background Value. Background values are used incases wherever there are missing intervals inside a solid.There are two ways of handling these missing samples.Select one of the following options:

◊ No. Select this option to have missing samples ignoredcompletely. These samples will not contribute to eitherthe grade or the length when the program calculates thelength-weighted grade for the interval.

◊ Yes. Select this option to have all missing valuesassumed to contain some entered grade. You must entera default value for each grade element that will be usedfor the length-weighted grade calculation. This isfunctionally the same as if the database had no missingsamples and all these additional intervals were set tothe default grade value.

• Use Threshold Value. Threshold values define the upperlimits of any grade values to be used in the calculation. Ifany sample exceeds the threshold value when this toggle isset to Yes, the sample will be set to the threshold valueitself. This process is commonly referred to as the “cutting”of high grade data. For example, if you were using percentcopper as a field, you may set the threshold to 10% for thefollowing reasons:

◊ to reduce the impact of outlying high grade samples onaverage grade estimates. Note that the samples are not

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excluded from the calculations; their values are merelyreduced to the threshold value.

◊ to find a more conservative result.

7. In addition to these parameters, all elements defined for yourproject (see Chapter 6: General Data Definitions and Chapter 9:The File Menu, Volume I: Core ) will appear in the dialog box.For each element for which you wish to assign grade values, youmust also enter the following parameters:

• Field for Element. Specify the name of the field that willstore the grade value for the element. An invalid entry willbring up a list of valid field names. Remember that the onlyvalid field entries will be fields contained within theselected table in the current drillhole loading profile.

• Threshold. If you selected Yes under Use ThresholdValue, above, you must enter a value here to be used as thethreshold value for the element.

• Background. If you selected Yes under Use BackgroundValue, above, you must enter a value to be used as thebackground value for all records with missing values.

8. When you have entered all desired parameters, click OK.

9. In the file name dialog box that appears, enter a path and namefor the report file. The report file will include the followinginformation for each solid:

• the grade assigned to the solid

• the total number of intersections with drillholes

• the total number of assay intervals processed and theircombined length

• the total number of assay intervals missing and theircombined length

• the volume and tonnage

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Click OK to proceed.

10. An on-screen summary will present the number of solidssuccessfully processed and assigned grades, and the name of thereport file. You can now view your results by using a DOS texteditor to access this file. The results of the calculations can alsobe displayed under the Solids menu using the Utils } EditSolid/Surface Attributes command.

Creating ASCII Files of Drillhole-Solid Intersections

This command will intersect all drillholes loaded in memory withall active solids. The results are saved to a user-specified ASCII filecontaining the following information about each drillhole/solidintersection interval:

• drillhole name• FROM distance• TO distance• solid name(s)• solid rock code (if intersected solid is geology class)

The records in the ASCII file are sorted first by drillhole name thenby FROM-TO distances. This allows you to track easily where thedrillhole enters and exits specific solids and rock types.

If the program encounters a surface instead of a solid (for example,if you are intersecting drillholes with a coal seam or fault) the FROM

and TO distances for that entry in the ASCII file will be the same.

Follow this procedure:

1. Select Solid }} Data }} Select Solids from List or Surface }} Data }} SelectSurfaces from List to activate the solids or surfaces that you wantto intersect with drillholes.

2. Select Drillhole }} Data }} Load Drillholes to load the drillholes thatwill be used for the solid/drillhole intersection calculations.

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Specify the desired database, drillhole loading profile, drillholedisplay profile, and workspace records.

3. Select Drillhole }} Drillhole Compositing }} Create ASCII File ofDrillhole/Solid Intersections and enter a name for the FROM-TO

ASCII file.

4. An on-screen summary will present the number of drillholesprocessed, the number of intervals saved, and the name of theoutput file.

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