What is Reverse Circulation (RC) Drilling? [Inc. Video]

Reverse circulation (or RC as it’s more commonly known) drilling is an essential tool in the mining industry. In addition to other oil rigs and drill rigs, reverse circulation drills assist in the productivity and accuracy in mining jobs.

RC drilling is a drilling method involving a large rotary drill and air compressor that yields high quality mineral and rock samples, free from contamination and material interference.

It is the preferred method of exploration, drilling and in-pit grade control because it is fast and cost-effective.

What is RC Drilling?

Much like air core drilling, RC drilling returns cutting to the surface through an inner tube inside the rod. This is achieved by blowing air down the rods at a rate up to 1500 Pascals. This creates a pressure differential that pushes cuttings and water up via air lift.

The drilling component is powered by a pneumatic reciprocating piston (also known as the hammer), which drives a steel drill bit.

The two most commonly used drilling bits in RC systems are the fixed cutter and roller cone, both of which are advantageous depending on the project and geographical location of the site.

RC drilling is primarily used on large machinery and drill rigs and often goes to depths of 500 metres. [Source]

High quality RC equipment also has the ability to dry out the rock with large air compressors before the drill hits, which provides dry rock chips and, in turn, better samples.

History of Reverse Circulation Drilling

The innovation behind RC drilling is proudly Western Australian.  During the middle of the last century, drilling in soft iron ore and mineral sands using the traditional open hole techniques was proving to be difficult. Due to this need, Bruce Metzke and John Humphries of Kalgoorlie created the first RC drill rods in 1972 [source].

As the years pass, the need for cleaner samples increased, which led to the development of the RC hammer in 1990. Around the same time, high pressure boosters and auxiliary were added to penetrate faster and to create deeper holes.

The introduction of this technology made RC drilling the most cost effective and accurate method available, particularly in an era where mining costs were rising.


In Western Australia, reverse circulation drilling is the predominant technique based on a number of advantages.

  • A higher percentage of uncontaminated cuttings
  • Drilling rate similar to open hole drilling, but can often be faster and penetrate greater depths
  • One of the most accurate drilling methods
  • Quick retrieval of sample rates
  • Dry samples allow for easier analysis

Reverse circulation drilling has earned a reputation for good results in the mining industry because of its ability to attain high quality samples and its cost effectiveness.  If you are after RC drilling machinery for your next project, please contact us for further assistance.

What is grade control and how can it save you time?

Traditionally, a geologist oversees grade control in the mining industry. However, over the past two decades, we have seen an emergence of technology that assists with this procedure. Today will take a closer look at grade control and how it can improve the mining industry.

What is Grade Control?

Grade control is an essential part of the mining process because the metal being extracted from the ground is never constant.he first grade control machines to have guidance systems were introduced in the late 1990s. Since then, this technology has become more prominent – many manufacturers of earthmoving equipment now offer guidance systems that control blades and other machine parts using GPS technology.

How does it work?

Drilling machinery provides the operator with real-time grade guidance while they are drilling. What this means is that they are given information about the desired depth, slope and alignments (which was traditionally given to them by a specialist inspecting the site). Drilling samples are sent to laboratories for geologists to access the grade.

Why use it?

Controlling the grade is important for two reasons:


The grade of the mineral can vary dramatically due to depth. Geologists will use this information to define the economic limits, to ensure there is return on investment when mining the mineral.

At one point in an operation, mining becomes unprofitable because the grade of the metal is too low – the value of the metal in the ore is less than what it costs to mine it. Grade control stops businesses from running at a loss.


The milling process is designed to be as efficient as possible by being performed at a specific grade. When mining in a high-grade zone, it is possible for some of the metal to be lost unless it is blended with low grade metal.


Grade control technology improves efficiency, increasing the productivity and profitability of an operation. Grade control systems allow machinery to operate at a continuous pace, rather than having to stop for a grade checker to come and measure the excavation, as with conventional equipment  – a process that often needs reworking. It also decreases the need to do prep work and to check the grade after the deck. The overall benefit is that it will save you time (and thus money), without compromising on accuracy.


We hope the information provided has given you an insight into grade control and its benefits. If you require a drill with grade control for your project, please contact us as we may be able to assist you.