Geodrill specializes in reverse circulation (RC) and diamond core drilling, and has recently added air-core drilling capabilities. Over half of Geodrill's rig fleet consists of multipurpose rigs, which have the ability to perform both RC and core drilling. This gives the Company the flexibility to transition mid-way through a hole based on client requirements with one rig, rather than having two rigs on site. This versatility reduces costs associated with mobilization and demobilization, and effectively reduces the realized cost per meter associated with a drill program.
The different types of drilling services offered by Geodrill are summarized below:
Air-Core – Air-core is reverse circulation drilling using a tungsten blade. It is ideal for shallow drilling in soft or medium formations. It is relatively inexpensive and is mostly used in first pass exploration drill programs. Air-core drilling is limited to blade refusal depths of about 75 meters, depending on the rock type. It is drilled using a small mobile rig called a Air-core rig.
Reverse Circulation (RC) – Reverse Circulation (RC) is the method of choice for obtaining consistently high quality rock chip samples with speed and efficiency. RC drilling typically drills into the ground to depths of, typically, about 200-400m. In terms of pricing, this drilling methodology is centrally positioned , i.e. more expensive than air-core drilling, but less expensive than diamond core drilling. Samples are collected from depth using a percussion RC hammer, which is pneumatic-driven, and pulverizes the rock, which is then transferred to the surface through an inner tube and collected via a cyclone and into a sample bag.
Diamond Core – Core drilling is a system that drills and collects a core (cylindrical) sample in the state in which it is found, i.e. in situ. The system known as ‘wire-line coring’ is used, i.e. a diamond impregnated (hollow) core bit is used which cuts until the core barrel is full. Drilling mud/cutting oil cools/lubricates the drill bit and acts as medium for lifting cuttings to surface. This method is used to drill to depths up to 1500m. A diamond-impregnated drill bit cuts a core of rock, hence it is often referred to as 'diamond' coring. The core sample is removed at intervals, usually 3 meters, and catalogued.