Getting the longest life possible for your core bit is key if you want to run a productive and profitable drilling operation. Changing a drill bit takes time especially the farther down the hole it is, and the time spent replacing a bit is not useful.
Let’s say a bit averages about 125 meters. In this case, if you have to drill 1000 meters you can expect to change the bit 8 times. If you can extend the life of a bit by only 15%, you can expect one less drill bit replacement. The further into the hole you’ve drilled, the more time saved this represents. At about 800-1000 meters, it can take up to 4 hours to replace a bit. So here are 6 tips that can help you try and get that extra 15%.
Choose the right bit for the hardness of rock you will be drilling in. The hardness of the ground is measured according to Mohs Hardness scale, a chart of relative hardness of various minerals. The scale consists of numbers one through ten; 1 being the softest and 10 being the hardest. Drill matrices are developed to perform ideally within a certain range of the scale so you need to pick a bit suitable to the hardness of the ground to be drilled. There are tools that help you identify the hardness of the ground such as an Etcher kit or scratch test. See a video on how to determine rock hardness here.
- Use drilling fluid additives - Reduction of torque leads to longer life of your drilling equipment. Torqueless, an environmentally safe product can be used alone or in combination with other additives to lubricate, reduce wear and rusting of the rods and cool the core bit. It is often used with DD-2000. It also raises the viscosity of the drilling fluids so that cuttings can be more easily flushed out. One added benefit is that it is non-abrasive and helps cool and protect the core bit when mixed with Torqueless, resulting in longer bit life.
Choose the right waterway configuration. You should consider waterway configurations that specifically address the conditions you encounter.
Confirm water flow: Make sure there is proper and sufficient water flow to the bit. Make sure that your rods don’t leak Proper flow and pressure at the bit face will make sure rock cuttings are flushed and the bit is cooled.
- Use a higher crown configuration - The Vulcan is a configuration option that allows you to extend your core bit life. It refers to the height of the crown and currently comes in 16 or 26 mm. The higher the crown the more meters you can achieve before having to change a bit and this is important when you are drilling a deep hole. The Vulcan configuration was designed with a bridge technology that reinforces the diamond sections. In the case of the Vulcan 26mm the secret of its success is its water management system. It is constructed with vertical pins under the bridge that ensure good fluid circulation all the way to the crown. The pins are made from the same alloy used in the matrix and will wear at the same rate. Once you reach the mid-point of the bit, they will drop out and allow full water flow to the face. These features ensure proper flushing and cooling of the crown and allow you to use every millimeter of the matrix.
Use a crown matrix that is customized for type of ground, i.e. abrasive ground , such as the HERO Abrasive line, that have been developed specifically for abrasive ground conditions. These bits have a special matrix consisting of alloys and diamonds that when combined, are very resistant to abrasive conditions and are easy to sharpen in the hardest conditions.
Getting longer life is important for all your drilling equipment, but since the core bit represents an investment and does the actual cutting, it is benchmarked by many drillers. If you are having a hard time getting good life from your core bits in specific ground formations, try giving our technical team a call. They are ready and able to share tips and advice that will help you improve your bit life.