Drillhole Quality Control and Quality Assurance

The Drillhole system performs a small number of vital Quality Control and Quality Assurance (QA/QC) tests when importing your data. These tests include anything that will impact the whole project, for example duplicated Hole IDs. An "Import.log" file will be displayed after importing if such problems are found.
It also provides the tools to enable you to perform detailed QA/QC tests on each of the five different data types (Collar Data, Dip/Azimuth Survey, Easting-Northing Survey, From-To Data, and Point Data).

Use the DH-Data > QA/QC menu option (DHQAQC GX) to perform Quality Control and Quality Assurance tests on Drillhole databases. In the Drill Hole - QAQC Tools dialog, select the type of data on which to perform the QA/QC tests. For each data type there are different sets of options that you can enable/disable using the Options button.

Each test produces its own log file, e.g., Collars.log (Collars data), FromToData.Log (From -To data), QAQC.log (all data).

To run the QA/QC test:

On the DH-Data menu click QA/QC.
The Drill Hole - QAQC Tools dialog appears.
From the Data type to QA/QC drop-down list, select the data type you want to perform the QA/QC test on. Select "All Data" to run the tests on all the data in your current project.
Using the Hole selection drop-down list, select to run the QA/QC tests on selected holes, all holes, or selected holes from list.
To access the list of options that the selected data type will use for testing, click the Options button.

The QA/QC- * data options dialog will be displayed. Depending on your selected data type, you will be presented with a list of QA/QC options.
Click the OK button to run the test. If no errors are found, a confirmation prompt will display; otherwise, a log will open and list the errors from each data type.
If you run this test on a data type that you do not have in your current project, a warning will display.

Drillhole – QA/QC Tools dialog options

Data Type to QA/QC

Select which type of data to QA/QC:

Collar Data

Dip/Azimuth Survey

Easting-Northing Survey

From-To Data

Point Data

Script Parameter: DHQAQC.TYPE

Options

The QA/QC options for the selected data type will be displayed.

QC Parameter Settings

The following dialogs appear when the Options button is selected on the Drill Hole – QA/QC Tools dialog.

QA/QC – Collar Data Options

Dummy East, North or RL	Values of East, North or RL that are dummy values are flagged.
Duplicated Locations	Duplicated collar locations are flagged. Though multiple holes can be drilled from the same collar, this may indicate a data entry error.
Reversed Easting/Northing	A simple test is performed on each collar location: The area covered by all the collars if each hole location (one at a time) is specified with Easting and Northings reversed is compared to the original area. This test succeeds because reversing the two values generally produces a location far away from the rest of the collars, and the total area covered by all the holes changes markedly. This test can break down if more than a single collar’s Eastings and Northings are reversed.
Dip out of range –90 to 90	Dips outside this range (which are not dummies) are flagged. On import, dummy dips are set to 90 or –90, depending on the defined dip sign convention.
Azimuth out of range -360 to 360	Azimuths outside this range (which are not dummies) are flagged. On import, dummy azimuth values are set to 0.
Dip sign discrepancy	If a dip value has the opposite sign of the current dip convention, it is flagged. This would indicate a hole heading back to the surface.
Top of hole depth less than 0	While the collar may be located at a distance down the hole from the original "Top" value, it cannot be located before the start of the hole itself. This error is reported just once per hole in any single database.
Hole depth less than 0	The hole depth should be greater than or equal to 0. Hole depths in the range 0 to 1.0 are reset to 1.0 on import so that the start of the hole will plot on maps. This error is reported just once per hole in any single database.
Hole depth less than top of hole	The total depth of the hole must exceed the location of the start of the hole.

QA/QC - Dip-azimuth Survey Options

Dummy Depth	Values of depth that are dummy values are flagged.
Depth less than hole top	Values of depth less than the defined hole top depth are flagged. This error is reported just once per hole in any single database.
Depth greater than hole bottom	Values of depth greater than the defined hole bottom depth are flagged. The hole bottom depth is automatically reset to the maximum hole depth defined in the survey. This error is reported just once per hole in any single database.
Duplicated Depths	Duplicated depth values are flagged. Only one dip-azimuth value can be defined at a single depth.
Out-of-sequence Depths	Depths that decrease from the previous value are flagged. Depths should increase. Out-of-sequence depths may indicate an error in the depth values. In practice, depths are sorted before the hole is re-surveyed.
Dummy Dip or Azimuth	Flags dip or azimuth values which are undefined. The last dip and azimuth for a hole may be left undefined (dummy).
Dip out of range –90 to 90	Dips outside this range (which are not dummies) are flagged. On import, dummy dips are set to 90 or –90, depending on the defined dip sign convention.
Azimuth out of range -360 to 360	Azimuths outside this range (which are not dummies) are flagged. On import, dummy azimuth values are set to 0.
Dip sign discrepancy	If a dip value has the opposite sign of the current dip convention, it is flagged. This would indicate a hole heading back to the surface.
Max curvature - degrees per meter (or feet)	One indication of erroneous depth, dip or azimuth values is the "creation" of a hole that bends crazily at a certain location. Curvature is the mathematical description of how fast the borehole bends. If this value is left blank, or zero, no check is performed. A maximum of 10 degrees per meter means that it would be okay if the hole could be formed into a circle with a circumference of 36 meters.

QA/QC – East-North Survey Options

Dummy East, North or RL	Values of East, North or RL that are dummy values are flagged.
Duplicated Locations	Duplicated depth values are flagged. Only one dip-azimuth value can be defined at a single depth.
Reversed Easting/Northing	A simple test is performed on each surveyed location: The horizontal (East-North) distance between successive hole locations is measured, then compared with the distance if the East and North values in the second location are reversed. This test succeeds because reversing the two values generally produces a location far away from the rest of the points, but has the opposite effect if the values were reversed to begin with. This test can break down if more than a single location’s Eastings and Northings are reversed.
Broken trend in RL	Generally a descending hole continues to descend and an ascending hole continues to ascend. This test flags locations where the change in successive RL changes sign. This can occur legitimately when a hole passes through the horizontal, but normally occurs due to an error in the RL value.
Max curvature - degrees per meter (or feet)	One indication of erroneous east, north or RL h values is the "creation" of a hole that bends crazily at a certain location. Curvature is the mathematical description of how fast the borehole bends. If this value is left blank, or zero, no check is performed. A maximum of 10 degrees per meter means that it would be okay if the hole could be formed into a circle with a circumference of 36 meters.

QA/QC – From-To Data Options

Dummy From or To	Values of depth that are dummy values are flagged.
From greater than To	Intervals are flagged if the "From" value is greater than the "To" value. Intervals cannot have negative thickness.
From equals To	Intervals are flagged if the "From" value is equal the "To" value. Some "Point" data sets are represented as From-To data sets with the From and To values equal, so this test is not always desired.
From or To less than hole top	No data can be plotted above the top of the surveyed hole. In practice, intervals are truncated to the top of the surveyed hole depth. This error is reported just once per hole in any single database.
From or To greater than hole bottom	No data can be plotted beyond the surveyed hole depth. In practice, intervals are truncated to the surveyed hole depth. This error is reported just once per hole in any single database.
Duplicated From-To intervals	Only a single data definition can exist for any given From-To interval, so duplicates will be ignored when plotting.
Out-of-sequence Depths	Depths that decrease from the previous value are flagged. Depths should increase. Out-of-sequence intervals may indicate an error in the depth values. In practice, intervals are sorted before plotting.
Overlapping intervals	Intervals are flagged if they overlap with the previous interval. The "From" of the second interval must be greater than or equal the "To" of the previous interval. A numerical tolerance of 0.00001 in the current units prevents numerical error from triggering this error message – the "From" must be less than "To" plus the tolerance in order for this error to be reported.
Missing intervals	Intervals where the "From" value is greater than the previous interval’s "To" value are flagged. In practice, this situation is often valid. Its presence in data that is supposed to be "complete" in depth may indicate an error in one of the "From" or "To" values. A numerical tolerance of 0.00001 in the current units prevents numerical error from triggering this error message – the "From" value must be greater than the previous "To" plus the tolerance in order for this error to be reported.
Duplicated sample numbers	In some data sets, such as geochemical data, each measurement is identified with a unique sample number or code. This test looks for duplicated sample numbers (codes).

QA/QC – Point Data Options

Dummy Depth	Values of depth that are dummy values are flagged.
Depth less than hole top	No data can be plotted above the top of the surveyed hole In practice, no data points less than the surveyed hole top depth are plotted.
Depth greater than hole bottom	No data can be plotted beyond the surveyed hole depth. In practice, no data points greater than the surveyed hole depth are plotted.
Duplicated Depths	Only a single data definition can exist for any given depth, so duplicates will be ignored when plotting.
Out-of-sequence Depths	Depths that decrease from the previous value are flagged. Depths should increase. Out-of-sequence depths may indicate an error in the depth values. In practice, data are sorted by depth before plotting.
Duplicated sample numbers	In some data sets, such as geochemical data, each measurement is identified with a unique sample number or code. This test looks for duplicated sample numbers (codes).

Application Notes

For each data type, there are a different set of options you can enable/disable using the Options button. All the options are enabled by default, except the hole curvature test. This parameter requires you to specify a value for the curvature -- if it is set it to 0 or left blank the test does notrun. The system saves the settings to the Advanced Settings file (Project > Settings > Advanced).

In addition to the above tests, the following checks are carried out:

The names of the lines (tables) in each database are compared against the list of holes found in the collar table.
The names of "unregistered" holes are written out. Data found in these lines is ignored by the system, and cannot be accessed for plotting etc. To remove unregistered lines, you can delete them manually as you would delete any line in a database, or you can use the "Remove unregistered holes…" (DHCLEAN.GX) found in the DH-Data menu.

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