Diamond core drilling has revolutionized the mining industry over the recent years. As a result, many ores are being discovered that would otherwise have gone untapped. Mining was dependent on finding boulders of rocks before diamond drilling was introduced. Very little information was available regarding ore concentrations below the surface within the earth. Diamond drilling makes it possible to remove solid cylinders of rocks from beneath the earth.
The Drill Rig
Diamond core drilling uses diamond bits. It is composed of a group of small, industrial grade diamonds set into a metallic, soft matrix and attached to the last part of hollow drill rod. You can attach more sections of pipe to the top of this to reach greater depth for drilling. The number of pipes or rods attached to the top of the drill rod is often used to estimate the depth that is drilled.
These types of drilling rigs can cut through a cylindrical rock-hard core. You can change the hardness of the matrix from brass to high-grade steel according to the rock, which has to be cut. Inside the small piece, there are hole that allow water to be carried to the cutting face for lubrication, cooling, and to wash away the drill cuttings from the opening.
Diamond drilling is typically slower than reverse circulation drilling because of the toughness of the ground being drilled. These diamond drilling rigs are extremely costly. That is why you need to drill little by little when using the rig to extend the life of drill bits and rods.
A lifter tube is used to take core samples. The empty tube is lowered within the rod string using a winch cable until it stops within the core barrel. The cable locks on to the backend on the top end of the lifter tube. As drilling progresses, the lifter tube slips over the core. The core lifter can then be dragged to the surfaced by the winch cable.
You then detach the core sample from the rod and record it. After cleaning and calculating the core, you break it down into small pieces using a hammer, creating it in shape and then place them into the sample trays. Geologist will collect the core trays and study the core samples to find out if the drill site is an excellent location for further mining operations.
Diamond drilling rigs can also be a part of a multi-combination rig. Multi-combination rigs are a twin setup rig, which are able to operate in either a reverse circulation or diamond drilling, but cannot do the two roles at the same time. This can be used in exploration drilling at extremely isolated locations.