When selecting a bit there are 3 main factors that contribute to decision making
○ Rock Hardness
○ Rock Formations
○ Bit Characteristics
• Rock Hardness
Measured using MOHS hardness scale: The Mohs scale of mineral hardness is a qualitative ordinal scale that characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material.
• Rock Formations
Rock types are classified by their different chemistry and structure. Hardness in theory is relative; therefore, soft rocks can prove more difficult to drill than hard rock. Also, the same rock formations, in different locations, can drill differently.
Factors that Determine Drillability
○ Grain Size
○ Rock Hardness
○ Weathering and Fracturing
• Bit Characteristics
Matrix – Each of the matrices has a different rate of wear. The matrix chosen is ideal when there is a balance between the wear of the matrix material and the diamonds exposing ensuring a high rate of penetration and optimum bit life.
Gauge – The outer (hole) and inner (core) dimensions of the bit
Crown Height – Ranging from 4mm to 18mm in height. With higher crowns available upon request. The height of the crown is chosen based of hole depth and wear rate.
Waterways – There are multiple different waterway configurations depending on the drilling conditions
HAYDEN uses a number reference guide (Hayden 1-16), corresponding to the matrix hardness for ease of selection. (Hayden 1 being the hardest matrix and Hayden 16 being the softest.) The higher the number, the harder, finer grained, more competent and non-abrasive the rock type the bit is capable of drilling. Conversely, the lower the number selected the more broken,fractured coarser grained and abrasive a formation the bit is capable of drilling.
We manufacture slight variances of the standard matrices to fine-tune the bits performance considering the drill rig capabilities and formations being encountered.
HAYDEN is capable of designing and manufacturing bits to any customer specifications and the worlds exploration industry.