FAQ &
glossary

Our footprint covers primarily the African region and extends beyond to the Middle East and Asia. Field operations run from South Africa, Ghana and Zambia, with crews mobilised to site.

Logging measures the formation where it sits, continuously, at centimetre scale, and in the same units on every hole. It fills the gaps where core is lost, replaces sparse laboratory samples with a continuous record, and delivers oriented structure without oriented core. The result is more and better data per metre drilled, usually within days of the hole being completed.

In-situ physical properties (density, natural gamma, resistivity, sonic velocity, magnetic susceptibility), fully oriented images of the borehole wall including zones of lost core, borehole geometry from the caliper, fluid properties and flow, and measurements that extend beyond the hole with radar. Core logging is descriptive; logs are quantitative and repeatable.

Yes. Every tool is calibrated against known standards before deployment, and calibrations are checked on site. Raw counts are converted to engineering units through documented calibration equations, and QA checks accompany every run.

Laboratory tests measure a small sample after it has been removed from confining stress, dried or resaturated, and sometimes damaged in handling. In-situ logs measure the rock under natural stress, saturation and temperature, over a much larger volume. The two are complementary: lab tests calibrate the logs, logs extend the lab results along the whole hole.

Depth is measured by a calibrated wireline encoder and tied to the collar. Runs are depth-matched to each other and to casing shoe or marker beds, giving typical accuracy of a few centimetres over hundreds of metres.

Logs are recorded along the hole as measured depth. Where a directional survey exists, we can deliver true vertical depth and 3D coordinates for every sample.

It depends on depth, the tool string and hole conditions. A standard multi-tool suite in a 500 m hole is typically a matter of hours, including rig-up. Imaging tools log more slowly than property tools. We plan the programme around the rig schedule so that drilling is not held up.

Yes. Rough or washed-out walls from percussion drilling degrade contact tools and images, while diamond core holes give the best imagery. Mud type, casing and hole fluid all matter too. Tell us the drilling method up front and we will select the tools accordingly.

Our slimhole fleet is designed for exploration and mining diameters, from around 45 mm upward, and includes tools for larger water and geotechnical holes. Individual tools have minimum and maximum diameters; we match the suite to the hole.

Some do. Natural gamma, gyro survey, temperature and certain nuclear tools read through casing; resistivity, televiewers and most contact tools need open hole. Enviro-Log includes casing inspection and screen location in cased monitoring wells.

No. Logs measure physical properties, and geology is interpreted from them. Because each rock type has a characteristic signature, interpretation is usually straightforward once the logs are calibrated against core from one or two holes.

Logs are depth-matched to core, then the log responses are calibrated against logged lithology, assays or geotechnical tests. From there the same signatures are recognised in holes with no core, or used to block lithology automatically.

Data is delivered in standard formats (LAS, CSV, WellCAD, images) that load into common mining and geotechnical software. If you would rather receive interpreted products, our geoscience team delivers lithology, structure and property logs ready for your model.

Yes, and it is well suited to it: continuous, numeric, multi-parameter and consistently sampled. Our data science team uses expert rules and machine learning for lithology classification, alteration mapping and predictive assay.

The caliper measures hole diameter. It corrects the other logs for hole size, shows washouts and breakouts that affect data quality, identifies fractured zones, and reveals in-situ stress direction through breakout orientation. It is the first log we look at.

Acoustic televiewers typically sample 1 to 2 mm vertically at 144 to 288 samples around the hole; optical televiewers are similar or finer. Millimetre-scale fractures and bedding are routinely resolved.

Open and healed fractures, faults, veins, bedding, foliation, contacts, vugs, breakouts, casing damage and, on optical images, colour, texture and mineralogy. Every feature is oriented with dip and dip direction.

The acoustic televiewer (ATV) images the wall with an ultrasonic pulse, recording travel time and amplitude, and works in muddy or opaque fluid. The optical televiewer (OTV) records a true-colour photograph of the wall and needs clear water or air. ATV emphasises open fractures and hole shape; OTV shows lithology and healed structure.

Each tool carries a three-axis magnetometer and accelerometers, so every scan line is referenced to magnetic north and to the high side of the hole. In magnetic ground or steel casing a gyro reference is used instead.

Rough or washed-out walls, hole ovality, thick mud or gas bubbles (ATV), turbid fluid (OTV), rapid tool rotation and off-centre tool position. A caliper log and centralisers address most of these.

Oriented core tells you the true dip and dip direction of every structure you log, which is what resource, geotechnical and mine design models need. Unoriented core gives angles to the core axis only. Where orientation is lost, televiewer images restore it.

They sense the Earth's rotation. A north seeking gyro measures the horizontal component of the rotation vector, which always points to geographic north, so it works inside steel casing, drill rods and magnetic ore bodies where a compass cannot.

No. Modern survey tools are designed for drill crews to run after training, with data validated remotely by our survey team. For critical holes we deploy our own technicians.

Yes. Survey results are exported from the tool and can be uploaded from site to your data system or ours, so deviations are seen the same shift rather than at the end of the hole.

Surveying can be performed while drilling occurs or after it has been completed. Regardless of which conventional method is used (single-shot, multi-shot or gyro), a successful survey delivers at each station:

• Survey measured depth
• Borehole inclination
• Borehole azimuth, corrected to the relevant north
• Magnetic field and magnetic dip
• Northing, easting and elevation
• Gravity tool face
• Dog-leg severity (DLS)
• Latitude and longitude