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Drill Hole Desurvey Calculator

Desurvey a drill hole by calculating interpreted XYZ positions from a collar and an ordered series of measured-depth, azimuth, and dip survey stations. GeoMiner implements the minimum-curvature equations published by the U.S. Geological Survey: adjacent orientations define a dogleg angle, a ratio factor fits a constant-curvature circular arc, and northing, easting, and true-vertical-depth changes accumulate from the collar to the toe. Outputs include every station coordinate, toe easting, toe northing, toe elevation, true vertical depth, horizontal displacement, bearing from the collar, dogleg, and dogleg severity. The calculator accepts two to fifty stations in metres or feet. The first station must be at measured depth zero and depths must increase strictly. Azimuth is clockwise from grid north. Dip uses the negative-down mining convention: zero degrees is horizontal and negative 90 degrees is vertically down. Collar easting, northing, elevation, and measured depths must use one compatible coordinate reference system and length unit. Confirm whether source azimuths are magnetic, true, assumed, or grid and whether declination and convergence corrections were already applied. Confirm the source dip convention, depth reference, units, collar control, horizontal datum, realization, epoch where relevant, projected grid, and vertical datum. GeoMiner does not transform coordinates or apply magnetic declination, meridian convergence, scale, elevation, datum, epoch, or unit corrections. Minimum curvature is an interpretation between discrete observations; it does not observe the path between stations or prove constant curvature. Survey-tool calibration, centralization, magnetic interference, gyro alignment, depth control, station spacing, transcription, and QA/QC affect the trace. Dogleg severity is geometric information, not an automatic engineering acceptance limit. This output is not survey-grade and does not establish a boundary, claim position, target intersection, true width, geological continuity, resource, reserve, ownership, safety clearance, or economic significance. Validate consequential work against raw and corrected surveys and approved professional software. Values remain in the browser. Analytics retain only bounded action, length-unit, station-count range, and trajectory-band categories—never coordinates, depths, azimuths, dips, hole IDs, projects,

Verification resources

Cross-check terminology, classification, methods, and safety with these authoritative external resources.

  • undefined. Publishes the minimum-curvature dogleg, ratio-factor, northing, easting, and vertical-depth equations used by this calculator.
  • undefined. Shows a processed borehole deviation survey with depth, inclination, azimuth, northing, easting, offset, and true vertical depth.
  • undefined. Explains spherical-arc or minimum-curvature desurveying, continuous direction at survey stations, and the importance of the dip-sign convention.
  • undefined. Defines desurveying as calculating XYZ coordinates from a collar and downhole survey data and explains limitations of straight-line methods.
  • undefined. Separates a trajectory calculation from the geological evidence and professional work required for resource and reserve classification.

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Common questions

What is drill-hole desurveying?
Desurveying calculates interpreted XYZ positions along a borehole from a collar coordinate and measured-depth, azimuth, and inclination or dip survey stations.
What does the minimum-curvature method do?
It connects adjacent survey orientations with a constant-curvature circular arc and uses a dogleg angle and ratio factor to calculate northing, easting, and vertical-depth changes.
Which dip convention does this calculator use?
It uses zero degrees for horizontal and negative 90 degrees for vertically down. Azimuth is clockwise from grid north.
Can I use only a collar survey and final depth?
Yes. Repeat one azimuth and dip at measured depth zero and final depth for a straight-hole projection, but do not treat the plan as evidence that the drilled hole stayed straight.
Is this result survey-grade or suitable for resource estimation?
No. Accuracy depends on collar control, CRS, corrections, tool calibration, station spacing, depth control, QA/QC, conventions, and implementation. Validate consequential work in approved professional software.

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