Drillhole Planning

The Drillhole Planner dialog

Drillhole Planner

To access this dialog:

Using the Sample Analysis ribbon, select Plan | Drillhole Planning.

The Drillhole Planner is a tool used to interactively plan exploration, infill and production drilling patterns. It can be used to create new plans or can modify existing plans, using a combination of interactive tools and fine-tuning controls. Drillhole Planner requires at least one static drillhole file to be loaded.

There's some background information about drillhole planning here.

Drillhole Planner provides a collection of tools for you to position, orient and modify holes. You can either create a new hole using interactive position (either onto the current 3D section or by snapping to any existing data. You can create hole data that starts or stops at a given surface or volume, or you can use two bounding wireframes to determine the collar and end-of-hole positions. You can also create a fan drilling design using a single collar and specifying multiple targets.

If hole data exists, you can offset any selected hole (using either the collar or target position, or both, as reference) to create a new hole. In this way, it's simple to build up a grid plan, say, for an initial exploration project on a greenfield site. Infilling for higher resolution data and getting your data over the inferred-indicated barrier, is just as easy.

If you know the dip, azimuth, sample/hole length and/or lift/drift deviation of your holes in advance, you can specify them and let Studio construct the hole for you. Otherwise, you can set the deviation (or deviations), target and/or collar positions and let Studio work out the starting dip/azimuth and path.

Existing holes are analyzed to determine their average lift/drift values, or if holes designed with Drillhole Planner are loaded, previously-specified values are retrieved and reported.

Any or all holes can be selected independently and modified (or removed), including setting an Overdrill distance. There is even a facility to record hole-specific comments.

Modifying the orientation, deviation settings, length or position of a hole will remove other attributes such as grade from the selected hole (as the position of the hole has changed, those values are no longer valid).

That said, if you have access to current model data, you can load that model and quickly re-apply the estimated values to the loaded holes. See below for more information.

Field Details:

The Drillhole Planner provides the following functions:

Drillhole Table: if no drillhole object has been defined as the current drillhole object when the Drillhole Planner is launched, a new object will be created ("New Drillholes") and automatically selected. Otherwise, select the loaded (and visible) drillhole object using this drop-down list.

You can set up the visual display settings for your new or selected drillhole using Format.... This displays the Drillhole Properties dialog for the selected object.

If <none> is selected, all drillhole planning controls will be disabled.

You can create a new Drillholes object whilst the Drillhole Planner is displayed, using the Current Object toolbar.

Attribute Model: if a geological or planning model is loaded, you can use it to code the current drillhole set. Select the model from the drop-down list and click Apply to all.

Hole Naming Convention: a drillhole naming convention of two parts can be set up using the Prefix and Start number fields. The convention will be used for the next hole that is generated (either interactively, or using the Offset function - see below):

Prefix: only available if the BHID field in your Drillhole Table is alphanumeric, this field is used to prefix drillhole identification strings generated by the Drillhole Planner. This will be suffixed by the Start Number (see below) to construct the final BHID for the next created hole.

Prefix can be any text description, including spaces if required. If the BHID field in your selected Drillhole Table is numeric, this field is disabled.

Start number: by default, a four digit string with leading zeroes is used as the borehole 'number'.

For an alphanumericBHID field: the Start number is a text string that will be added after the Prefix (see above) to construct the alphanumeric borehole ID for the next hole. Any alphanumeric string can be used in this case, although if a number is emulated (with or without leading zeroes), Drillhole Planner will increment the previous 'number' whilst maintaining its current format (for example: 0001, 0002, 0003 etc.).

If your BHID field is numeric: the Prefix field is disabled. In this case, the displayed number will also increase in sequence as holes are added, but the resulting BHID will be stored in the specified Drillhole Table as a number without leading zeroes.

As such, for both alphanumeric and numeric borehole IDs, the Start number will increment by 1 each time a new hole is placed, saving you the hassle of updating it (although you can edit it if you wish). The Drillhole Planner cannot create a borehole ID that is identical to an existing hole. Note that when a hole is created, if a hole already exists with the requested Start number, the first higher unused number found will be used instead, and the next Start number incremented from that point.

If you're not sure what holes already exist in the currently selected Drillhole Table, expand the Hole name drop-down list (see below) to see all holes currently available.

Add New Hole(s): the tools in this section are used to construct new hole data with in the current Drillhole Table. Holes will be added using the current Dip, Azimuth, HoleLength, SampleLength, StartDepth, Lift and Drift settings (see below).

Depending on how you design your new hole data, you can set up one or more of the following constraints in advance:

To define a new hole interactively, select the Interactively pick location check box. This opens up other design options. In this mode, the Add new hole(s) button acts as a toggle to start or stop the digitizing session (click to start, digitize as many holes as you need, click to stop). This mode will honour your current snapping settings.

If you wish to digitize the collar position of the new hole, ensure the Collar coordinate check box is selected in the Hole collar and path group below. Alternatively, you can digitize the target (end of hole) position by selecting the Target coordinate instead. Add new hole(s) will subsequently allow you to digitize a new hole or hole collar or target position.

In this scenario, the Hole length setting (see below) will be used to determine the length of the new hole (either down from the collar or up from the target).
If both Collar coordinate and Target coordinate are selected, you will digitize the collar position of the new hole.
Using left-clicking to digitize will add the collar or target position to align with the currently active section. Right-clicking can also be used to snap the new collar or target position to existing data, depending on your snapping settings. The snap-to-wireframe-data-on option can be particularly useful for snapping onto a wireframe surface. If both Collar coordinate and Target Coordinate are selected, clicking will define the collar position.
If the Snap elevation to surface drop-down list displays a loaded wireframe file (either a surface or a solid volume), new collar or target digitized points have their elevations vertically projected onto the wireframe surface.

To define one or more target or collar positions simultaneously using loaded points, select the From selected points option and ensure at least one point is selected and highlighted in any 3D window.

For example, to create a fan of holes from a single collar position, you would typically digitize or load the points representing the EOH positions and a single collar position would be selected in the 3D window using the pick button of the Collar coordinate control group, e.g.:

The Use target check box should be selected at this point, with the Coordinate option active.

Making sure the EOH positions are selected, clicking Add new hole(s) will generate a drillhole trace between the single collar position and all Target points, generating a unique BHID for each automatically.

The converse (setting multiple collars from a single Target), whilst unlikely, is also possible by selecting a Target position, then enabling the Collar coordindate check box, selecting collar points and using Add new hole(s).
To define a hole at an offset position from another hole, select the Offset from current collar/target check box. This facility lets you create a new hole at a given distance from the collar and/or target position currently shown in the dialog. This will usually be the currently selected hole, but can also be from a previous dialog session, if restored using the Restore button. This can be useful when planning a grid/fence of holes.

You can choose the Azimuth and distance (Offset spacing). Clicking Add new hole(s) will add a clone of the current hole at the predefined distance and direction from the current hole. At this point, the new hole becomes the current hole, allowing you to set up a row/grid of holes really easily.

You can choose to offset the current collar position of a hole, or the target position by selecting either the Collar coordinate or Target coordinate check box respectively. If both check boxes are enabled, the specified offset will apply to both target and collar.
No clicking is required if operating in this digitizing mode. Add new hole(s) will automatically position the next hole based on your current Offset spacing and Azimuth settings. As such, there is no opportunity to snap to loaded data, other than a loaded wireframe surface, if one is already specified in the Snap elevation to surface drop-down list.
You can rotate the Azimuth by 90 degrees clockwise or anticlockwise using the left and right arrow icons next to the Azimuth field. This can be useful when reaching the end of a row and offsetting to the next row.

You can also use the Azimuth spin buttons to incrementally adjust the angle.
If the Snap elevation to surface drop-down list contains [<none>], new collar or target positions will be aligned with the currently active 3D section (depending on whether Collar coordinate or Target coordinate is selected - if both are selected, the collar will be positioned).
If the Snap elevation to surface drop-down list contains a loaded wireframe surface, new holes will be projected vertically onto the selected wireframe surface. Where this means the hole will move outside the boundary of the selected wireframe, the elevation of the previous hole will be used instead.

In the example, below, a series of holes at 100m spacing have been added from East-West, snapping the target to the volume's upper surface. The final holes are position at the same elevation. The wireframe is shown with front clipping and an overlaid intersection line:

The Offset from current collar option is particularly useful for producing holes with shared collar positions (e.g. as part of an underground fan drilling program). By setting the Offset spacing at 0 (zero), you can add a new hole then select (only) the Collar coordinate check box, then change the Dip/Azimuth etc. of the new hole. The resulting hole will share the collar coordinates of the original.

For example, in the image below, a collar position is shared by 12 holes of equal length, varying by 40 degrees in Azimuth between successive hole BHIDs (and a dip of 80 degrees for all):

Select Planned Holes: all holes associated with the Drillhole Table (see above) are listed here, as distinguished by their unique BHID reference. Generally, this list displays the last created borehole ID, but you can choose any of the current holes using the drop-down list.

Selecting a hole will highlight it in the 3D window, and will update the Hole collar and path and Deviations settings shown below.

You can delete a hole by either clicking into the 3D window and pressing <DELETE> or using the red cross icon. You can also use box-selection techniques in the 3D window to delete holes if you wish, as the Hole name list will automatically update to reflect any recent changes.

Even if there is no hole selected, the Hole collar and path and Deviations controls are still enabled. This allows you to set up the required design parameters for the next hole to be digitized, using Add new hole(s). The only time these controls are disabled is where a Drillhole Table has not been selected, or the current table has been unloaded.

For each selected hole, you can add a Comment. This text can be used to record important information about individual holes, e.g. "To intercept main orebody".

The Hole name field has a right-click context menu, containing some useful commands relating to the selected hole, allowing you to Rename, Look at or Delete the selected hole, e.g.

You cannot rename a drillhole if that BHID name is already used by an existing hole within the same drillhole object.

A drillhole name cannot be empty.

Hole Collar and Path: this group of controls is used to both edit hole position, composition and orientation settings and view auto-calculated values. It is also used to set the general dip convention for the hole values that are displayed (either positive upwards or downwards).

This section also lets you set the origin position of the next hole; either the Collar or the Target, and interactively position the target and collar of the selected hole. You can also adjust these milestone positions to any point in 3D space using set values.

Collar/Target coordinate: select the corresponding check box to edit the XYZ position of the currently selected hole target or collar.

If only the Collar coordinate check box is selected: you can edit the 3D location of the collar position and/or interactively pick a 3D window location using the corresponding picker tool (which will automatically update the XYZ fields).

In this case, you cannot edit the target location directly, but you can edit the Dip, Azimuth and Hole length values (and Deviations) to adjust it indirectly: in this situation, the Target coordinate values are automatically calculated. For example, the image at the top, below, shows a default drillhole with a 90 degree Dip, meaning the only difference between collar and target is the depth value. On the bottom image, the Dip is reduced to 80 degrees, automatically adjusting the Target coordinate values:

If the Collar coordinate check box is selected, this also instructs Drillhole Planner to position the next hole (offset or manually positioned) using the mouse to define the collar (not the target) of the hole.

If Collar coordinate is selected and an offset hole is applied, the next hole will be offset at the collar and maintain the specified Dip, Azimuth, Hole Length and Deviations to position the next parallel hole. New offset hole collars will be snapped to a surface if one is specified.
Similarly, if the Target check box is selected, you can manually or interactively set the target location for the active hole by selecting the Coordinate option. This will automatically calculate the collar position by adjusting Dip, Azimuth, Hole length and/or Deviations.

If the Target check box is selected (and the Coordinate option selected) this also instructs Drillhole Planner to position the next new hole (offset or manually positioned) using the mouse to define the target (not the collar) of the hole.

If Target and Coordinate are selected and an offset hole is applied, the next hole will be offset at the target position and maintain the specified Dip, Azimuth, Hole Length and Deviations to position the next parallel hole. New offset hole targets will be snapped to a surface if one is specified.
If both Collar coordinate and Target/Coordinate check boxes are enabled, the Dip, Azimuth and Hole length settings will be automatically calculated, and so are disabled for input. You can still apply deviations, as deviations will be applied between collar and target, anchoring their positions to the given tolerance (this tolerance can be configured in the Advanced Settings dialog). You can also still edit the Sample length of the hole and any planned Overdrill setting in this case.

If both Collar coordinate and Target/Coordinate check boxes are enabled, the next new hole will be digitized by defining a collar position, with the target being set to the preset XYZ values.

In this case, creating an offset hole will be offset at both collar and target positions and maintain the specified Dip, Azimuth, Hole Length and Deviations to position the next parallel hole. New offset hole collars will be snapped to a surface if one is specified.
If the Target radio button is selected, and Surface is selected, this instructs Drillhole Planner to locate the end-of-hole position in relation to a loaded surface or volume (the wireframe object is selected from the corresponding drop-down list; only loaded objects are listed).

You can choose from the following options:

Reaches: terminate the hole at the first point the hole intercepts the specific wireframe object or preselected wireframe triangles (you can edit the way wireframe data is selected using the Project Settings Wireframeing panel), even if there are multiple intercept points (such as with a 3D volume, or a folded structure).

You can either specify a target wireframe object, or "<selected triangles>", meaning any wireframe surface or partial surface (in any loaded object) can be used as a terminating surface.

Overdrill (see below) will be added afterwards, if it is specified, causing the hole to push through the surface by the specified amount. This is regardless of the direction from which the hole intercepts the surface or volume.
Enters: similar to the [Reaches] setting above, this is used where you wish to terminate the hole at the point it first intercepts a boundary of a surface or volume. This is useful where a structure volume denotes the end of the hole. Overdrill will be applied if it is specified. For example:

As with the other options in this group, your target wireframe can either be a loaded wireframe object or any selected wireframe triangles (within one or more loaded objects).
Exits: in this case, the final intercept of the hole and surface/volume will be used to terminate the hole. This is useful for progressing a hole through a mineral-bearing structure for example, terminating the sample as it leaves the structure. For example:

Enters: similar to the [Reaches] setting above, this is used where you wish to terminate the hole at the point it first intercepts a boundary of a surface or volume. This is useful where a structure volume denotes the end of the hole. Overdrill will be applied if it is specified. For example:

As with the other options in this group, your target wireframe can either be a loaded wireframe object or any selected wireframe triangles (within one or more loaded objects).

Dip: for the selected hole, choose the dip value. The default is 90 degrees using a positive downwards convention (= vertically down from the collar). You can choose a positive upwards convention by disabling the Positive downwards check box if you wish. This will automatically invert the Dip value shown.

Dip values must be between -90 and 90.

Offset holes will store data internally using a positive-downwards convention, but will be displayed as positive upwards values in the Drillhole Planner if the Positive downwards check box is disabled.
Azimuth: set the Azimuth of the hole in degrees. Values must be between 0 and 360.

Changing the dip convention does not modify your drillhole data table; all values in the input table are assumed to be Positive downwards, and this is how all values are exported to the component tables using the Save to Tables function below. Changing the dip convention simply transforms the way the Dip values are entered and displayed in the Drillhole Planner form.

Hole length: defines the length of the current hole. If you are fitting the hole to both a collar and target coordinate, then hole length will be automatically calculated and shown on the dialog, but will not be editable.
Overdrill: defines the distance past the target the hole must extend. This does not normally affect the hole length itself, but simply downhole depth at which the target occurs. One exception to thisis when defining holes using both collar and target position. In this case, the resultant hole length will that sufficient to travel between the collar and the target, plus the required overdrill distance. The effects of overdrill are particularly obvious when defining target position, for example by snapping to a wireframe surface. In these case, the hole will not terminate at the surface, but will continue the specified overdrill distance past it: e.g.
Deviations

Depending on the type of drilling, the drill rig operator and the physical nature of the rocks that are being drilled through, you can potentially end up with the final/actual drillhole segments being off the planned target. The controls in this section allow you to plan these deviations into your project. Deviations can be applied at any depth down the hole and multiple deviations down the hole are permitted.

Lift and Drift deviations are defined in degrees. You can choose the amount of deviation, and the distance over which the deviation will be applied (for example, a lift deviation of 1m over each 100m of the hole). You can use a combination of Lift and Drift deviations in the same hole. Drift and Lift can be positive or negative values.

Lift is the change in the dip of the hole, and drift is the change in the azimuth. From the collar to the Start depth down the hole, the segments will have an azimuth and dip matching that defined earlier in the dialog. For any distance past the start depth, the azimuth and dip have the drift and lift added respectively. The direction of Lift matches that of the dip, and is controlled by the Positive downwards checkbox.

Although it's a nonsensical outcome, one way to visualize Lift and Drift is to imagine a vertical hole viewed from in an East-West orientation. Applying a 360 degree Lift over the exact length of the hole will result in the hole forming a circle, with coincident collar and target positions - this is an extreme representation of Lift. Starting with the same vertical hole and applying a Drift over the full length of the hole makes the hole appear as a circular outline in plan view but a corkscrew shape in an isometric view:

The resultant trajectories for different combinations of starting azimuth and dip may be very different, even with the same drift and lift combinations. For example, vertical holes would not be affected by changes in azimuth resulting from drift, but horizontal holes would be impacted quite significantly.

Where deviations are applied, Drillhole Planner will attempt to maintain the Collar coordinate if that check box is enabled, or the Target coordinate if that check box is enabled. If both of these check boxes are enabled, deviations will be applied whilst attempting to maintain the position of both target and collar (within the set tolerance - see below). If neither check box are enabled, drift and lift cannot be applied to the selected hole.

Multiple lifts and drifts can be set down a hole, using the supplied Deviations table, all deviations are defined using the supplied table, and to the selected hole. A hole ID must appear in the Hole name field before deviations can be defined.

You add a new deviation to the currently selected hole using the "+" button. The first deviation record will be placed at the collar position (Depth, Lift and Drift will be zero). You can edit any of the specification fields and add as many deviations as you need down the hole. Deviations will be applied at the set depth and either until the end of the hole or the next deviation in a downhole direction.

You can remove any deviation from the table using the corresponding "X" button.

For example, in the image below, 3 deviations are applied. The first extends from 0 to 100m, with a lift of 50 degrees every 100m. The next deviation is applied from 100 to 150m with -100 degrees per 100m and finally, from 150 to 200m, the original deviation 50 degrees per 100m is set:

Editing the Lift and Drift Scope

By default, lift and drift settings (degrees) will be set per 100 measurement units. You can change this independently for Lift and Drift using the Show lift per and Show drift per settings.

When you are specifying Lift or Drift degrees values in the Deviations table, the deviation will be applied based on the current Show lift per and Show drift per settings.

Subsequently adjusting the Show lift per and Show drift per values will automatically update the table values (not the drillhole data) to show the new Lift and Drift values with the altered distance(s). All Drift and Lift values in the table are shown based on the currently set distance values (for example, double the Show lift per value will also double all Lift values shown in the table).

How Deviation Data is Stored and Retrieved

Holes that have been created by Drillhole Planner will include information about Drift, Lift and Start depth settings, if any were previously specified.

Where holes have been loaded from other sources, Drillhole Planner will estimate the deviation values of each hole based on their relative orientation. These estimated values are purely for guidance and don't necessarily represent a definitive 'truth', but can be considered a 'best guess' from which to apply further deviations if required. Where deviation values have been estimated, you will see the following message:

Any Drillhole Table created or modified in Drillhole Planner will automatically be extended to include these additional deviation attributes.

You can add more than one equally-spaced deviation record to the table by selecting Add Rows. This will display the Add Multiple Deviations dialog.

You can copy and paste deviation values from Excel into the Deviations table.

Restore: when you close Drillhole Planner, a copy of your current planning settings is saved. You can retrieve these settings with the Restore button.
Advanced: access advanced settings for Drillhole Planner:

Fitting Tolerance: this setting determines how accurately target and collar positions of new or modified holes must match coordinate values that are locked. The default is 1, meaning that your hole target and/or collar must be within 1 measurement unit of locked values. For example, considering the X coordinate of a collar alone, and a Lift deviation is being applied to an existing hole. If the Target coordinate check box is enabled, an attempt will be made to match the current target position within 1 measurement unit.

You can reduce this tolerance to ensure a more accurate fit, but an increasing tendency for a failure to create a hole in particularly complex data sets.
Maximum number of passes: Drillhole Planner makes several attempts to find and refine the optimum fit for your drillhole settings. By default, 10 attempts will be made to design a hole that falls within the given Fitting Tolerance for both target and collar positions (whilst maintaining all other settings). You can increase this value if a hole solution cannot be found for your settings, but doing so can increase the time taken to provide a result.
Maximum hole length allowed: in extreme cases where a sensible solution cannot be found, a hole may be created of an arbitrarily long type, for example, if lift and drift settings make it impossible to return a practical result for a new hole. You can limit the maximum hole length permitted using this value. If a hole cannot be created below the specified length, an error message is displayed:

Save to Tables: output component drillhole tables in CSV format (collars, surveys, samples) using the Save Drillhole Tables dialog.