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How to Select Core Bit

Initial Selection

Select any of the steps below for additional information.


1. Determine the ROCK HARDNESS
  • For LOW rock hardness (≥ Mohs 4), select a Dimatec matrix type with a lower number designation. Appropriate selections may include S3 or S6.
  • For HIGH rock hardness (~ Mohs 7), select a Dimatec matrix type with a higher number designation. Appropriate selections may include XT13 or XT15.

XT-Series and S-Series Matrix Selection Chart

2. Determine the ROCK GRAIN SIZE
  • For a COARSE grain size formation, select a Dimatec matrix type with a lower number designation. Appropriate selections may include S3, S6 or XT7.
  • For a FINE grain size formation, select a Dimatec matrix type with a higher number designation. Appropriate selections may include S12, XT13 or XT15.

XT-Series and S-Series Matrix Selection Chart

3. Determine the FORMATION
  • For BROKEN and FRACTURED conditions, select a Dimatec matrix type from the abrasive conditions group. Depending on the rock hardness and grain size, appropriate selections may include S3, S6 or XT7
  • For MASSIVE and CONSOLIDATED conditions, select a Dimatec matrix type from the competent conditions group. Depending on the rock hardness and grain size, appropriate selections may include S12,XT13, or XT15.

XT-Series and S-Series Matrix Selection Chart

4. Consider the type of DRILLING EQUIPMENT
  • For a LOW POWERED or lightweight drill, adjust your matrix type selection by choosing a slightly softer (higher matrix designation number) Dimatec matrix type.
  • For a HIGH POWERED or heavy duty drill, adjust your matrix type selection by choosing a slightly harder (lower matrix designation number) Dimatec matrix type.

XT-Series and S-Series Matrix Selection Chart

5. Select the CROWN PROFILE
  • The V-Ring Profile is the standard for all wireline core bits as well as non-wireline types with kerf widths greater than 7mm (0.27 inch).
  • The Flat-Face Profile is the standard for thin wall core bits with kerf widths of less than mm (0.27 inch). Occasionally used on thick kerf bits in heavily fractured formations.
  • The Semi-Round Profile is recommended for use on core bits with large kerf widths of 25mm (0.98 inch) or greater.
  • The Tapered Profile is limited to core bits with kerf widths of 8.5mm (0.34 inch) or greater. Recommended for use when  drilling past in-hole deflecting wedges or when addressing hole deviation problems.

Impregnated Core Bit Crown Profile Selection

6. Select the WATERWAY
  • A bit’s waterway configuration controls both the in-hole hydraulics (flushing) as well as the contact area (extent of cutting surface) that is presented to the rock face.
  • Low contact area bit faces tend to be more free cutting while high contact bit faces tend to provide better bit life.
  • Waterway configurations that feature wider canals are recommended for use in deeper drill holes. (≥ 300 metres or 1000 feet).
  • Open, low contact waterway configurations such as the “Turbo” style should not be used in fractured conditions. “Turbo” style
    waterways should not be selected for use where drill hole depths exceed 300 metres or 1000 feet.

Impregnated Core Bit Waterway Configurations

7. Select the IMPREGNATION
  • Refers to the thickness of the diamond impregnated matrix layer on the face of a bit.
  • Most types of wireline core bits are offered with impregnation depths of 6mm (0.24 inch), 9mm (0.35 inch), 12mm (0.47 inch) and 16mm (0.63 inch).
  • Thin-wall core bits are typically offered with impregnation depths of 6mm (0.24 inch) or 9mm (0.35 inch).
  • Consider the use of thicker impregnation depths for deep hole drilling applications to reduce the need for additional rod tripping.

Core Bit Impregnation Depth Configurations

8. Consider the OPERATING PARAMETERS

See the operating parameters page.


Fine Tuning

Matrix Selection Chart

Click here to download the Matrix Selection Chart in .pdf format. (55kb)

Dimatec’s system for diamond impregnated matrix identification provides a simple means of determining the correct matrix type to use for your job. The various matrix types are identified as code numbers such as S6 or XT10. The alpha component designates the matrix series while the numeric component designates the relative hardness of the bit’s matrix. In general, a diamond impregnated bit with a low identifying number such as S3 would be used to drill a soft, fractured and abrasive formation. As the numbers increase, the matrices are intended for use in increasingly harder formations up to the highest number, XT15, which would be used to drill an ultra hard, highly consolidated, non-abrasive formation.

When selecting a matrix type, consideration should be given to the capabilities of the drilling equipment in terms of its ability to function within Dimatec’s recommended operating parameters. It may be necessary to select a harder or softer XT-Series or S-Series matrix type than what is recommended in the Dimatec matrix selection chart in order to address drilling equipment limitations. Consideration should also be given to variations in geological conditions that may require the use of more than one matrix type on a particular job site.

Testimonials

“325 meters with our bits very good in medium hard rock. Thank you!”

– Ontario, Canada

“The successful trial results of the bit prove this bit to be a serious alternative to our current bit of choice at our mine.”

– Australia

“I have a result from a new client in northern Ontario. Their last bits went 60 or 80 meters and with Dimatec bits 212 meter! Good production thank you.”

– North America

“We received the bits yesterday! We are quite pleased with all aspects of this order including the 4-day lead time. Thank you for the expedited service!”

“The meters drilled were above ‘the norm’ and we were well within and even under budget lets say…”

– Canada

“We had a good wear on the crown, the meters achieved are also worth commenting on being consistently all right around the 300’ mark. We’re happy and the reaming shells are also performing well.”

– North America

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