geologic

Geologic Sampling: Drilling Techniques

When drilling, samples (in the form of core or chips) are returned to the surface for physical and chemical analysis.

Drilling occurs for various purposes:

To define lithologic contact depths

To obtain samples from the subsurface

To access mineral or energy resources

Click on play to see the different characteristics to choose a drilling method

Geologic Sampling: Drilling Techniques

The choice of drilling type depends on desired:

Available energy

Geology of the materials to be drilled

Type of samples needed

Stability of soil

Cost

Terrain

Accessibility

Time available for execution

Diameter

Depth

Geologic Sampling: Drilling Techniques

Click on each image to learn more about the drilling techniques

Open Hole Percussion (RAB)

RC (ReverseCirculation) Drilling

Diamond drilling

Open Hole Percussion (RAB)

The RAB drilling technique is adaptable to different terrain and rock types. It has a relatively low cost compared to the other techniques and is also easy to maintain. During drilling, samples return to surface on the outside of the drill casing creating high potential for sample contamination. Open Hole Percussion may be used for prospecting and determining geometry of a deposit.

Geologic Sampling: Drilling Techniques

Click on each image to learn more about the drilling techniques

Open Hole Percussion (RAB)

RC (ReverseCirculation) Drilling

Diamond drilling

RC (Reverse Circulation) Drilling

In this method the flushing fluid circulates down between the wall and the pipe and rises with the remains inside the pipe.

• Drilling action: Rotary and/or Impact

• Air drilling (chip samples <3cm)

• Sample return to the surface inside the drill casing

• Minimal sample contamination

• Suitable for resource drilling where quality is required

• Sample recovery reduced in heavily fractured areas

• Less water intensive than diamond drilling

• Lower cost than diamond drilling; fast drilling rate (>100m/day)

Geologic Sampling: Drilling Techniques

Click on each image to learn more about the drilling techniques

Open Hole Percussion (RAB)

RC (ReverseCirculation) Drilling

Diamond drilling

Diamond drilling

Diamond drilling is the ideal method for obtaining samples when performing research, as the original structure of the core is undisturbed.

• Drilling action: Rotary

• Allows the direct observation of rock and soil structure

• Most complete sample recovery, minimal contamination

• Core sample provides greater geological knowledge; allows for physical/calcination testing of limestone or dolomite; geotechnical testing

• Best for resource determination (drill depths >1km)

• Large amount of water is needed for lubrication and removal of debris

• Higher cost than other types

• Slower drilling rate (~50 meters/shift)

Geologic Sampling: Drilling Techniques

RC (ReverseCirculation) Drilling

Open Hole Percussion (RAB)

Diamond drilling

Drilling comparison table

Drilling videos

Diamond Drilling

Open Hole Percussion (RAB)

Drilling videos

Geologic Sampling: Drilling Techniques

RC (ReverseCirculation) Drilling

Diamond drilling

Open Hole Percussion (RAB)

Drilling comparison table

Drilling videos

Drilling comparison table

Open Hole Percussion RAB Drilling

Diamond Drilling

Reverse Circulation RC Drilling

Medium

Cost

Low

High

Deep<2 km

Shallow ~30 m (limited by air pressure)

Moderate<500 m

Maximum Depth

Fast >100 m/day

Fastest >150 m/day

Slow < 50 m/day

Drilling Rate

High potential for sample contamination

Most complete sample recovery, minimal contamination

Quality of sample for testing?

Minimal sample contamination

In this method the flushing fluid circulates down between the wall and the pipe and rises with the remains inside the pipe.

The drill uses a diamond encrusted drill bit to drill through the rock. The drill produces a "core" which we split longitudinally.

Samples return to surface on the outside of the drill casing.

Description of technique

Diamond drilling is the ideal method for obtaining samples when performing research and resource determination, as the original structure of the core is undisturbed.

Suitable for resource drilling where quality (lack of contamination) is required.

Highly adaptable to different terrain and rock types. Best type for prospecting and determining geometry of deposit.

Other

Geologic Sampling: Drilling Techniques

Open Hole Percussion (RAB)

Diamond drilling

RC (ReverseCirculation) Drilling

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