Exploration drilling sits at the front end of every mining decision worth making. The ore body might be there, the geophysics might be promising, but until a drill rig turns over the first hole, none of that translates into a defensible resource estimate. For mining companies operating in Queensland, choosing the right drilling contractor and the right drilling method has a direct impact on data quality, project timelines, and the cost per metre that flows through to your investors.
At Darr Drilling, we have spent more than 40 years working alongside major resource companies, including Rio Tinto and Xstrata, on exploration programs across Queensland. This guide sets out what you should expect from a serious exploration drilling partner, and the technical decisions that shape every program.
The Short Version
Mineral exploration drilling in Queensland typically progresses from cheaper, faster reconnaissance methods like aircore and RC through to higher-cost diamond core drilling as confidence in the target grows. A capable contractor handles all three, manages compliance and HSE on remote sites, and turns drilling data into something your geologists can actually defend.
The Three Methods Every Exploration Program Uses
Most mineral exploration programs in Australia rely on three drilling methods. Each has trade-offs in cost, speed, and the quality of data it returns, and a well-designed program uses them in sequence rather than picking just one.
Reverse Circulation (RC) Drilling
RC drilling was invented in Kalgoorlie in the mid-20th century and remains one of the most common methods used in Australian mineral exploration. The rig uses dual-wall drill rods with a pneumatic hammer at the bit face. High-pressure compressed air travels down the annulus between the inner and outer tubes, drives the hammer, and pushes rock chip samples back to the surface through the inner tube. Because the samples never come into contact with the borehole wall, contamination risk is low.
RC is the workhorse of mid-stage exploration. Holes routinely reach depths of around 500 metres. Daily production rates can exceed 200 metres in good ground. RC also uses considerably less water than diamond drilling, which matters in remote Queensland conditions.
Diamond Core Drilling
Diamond drilling uses a diamond-impregnated bit to cut a continuous cylindrical core of rock. The intact core preserves rock textures, structures, alteration, and mineral relationships in a way that chip samples cannot. For resource estimation, feasibility studies, and detailed structural geology, diamond core is the gold standard.
It is also slower and more expensive than RC, so most companies reserve it for targeted follow-up on promising RC intercepts or for deeper, more structurally complex deposits.
Aircore and RAB Drilling
Aircore drilling is well suited to soft, weathered cover and shallow regional reconnaissance. It is cheap and quick, which makes it the right tool for first-pass programs across large areas where you are still defining where to focus more expensive work.
A Typical Program Workflow
How an exploration program normally runs
Regional reconnaissance
Aircore or RAB drilling across broad target areas to confirm geology and prioritise follow-up.
RC infill drilling
Targeted RC programs to define grade and continuity within priority zones.
Diamond core verification
Diamond holes to capture structural data, density, and metallurgical samples for resource modelling.
Resource definition and reporting
Drill data feeds resource estimation and supports JORC-compliant reporting through to feasibility.
What Matters When Choosing an Exploration Drilling Contractor
Drilling rates and rig availability are the easy part to compare. The harder questions are whether a contractor can manage a remote site safely, whether their crews understand the geology well enough to make sensible decisions in the field, and whether their HSEQ documentation will survive an audit. Our crews operate under an Integrated Management System maintained to ISO 9001 and Australian Standard 4801, which is the standard most major resource companies expect on site.
Stats That Shape Decisions
Talking to Darr Drilling About Your Program
If you are planning an exploration phase in Queensland, the right time to talk to a drilling contractor is well before you finalise your program design. Drill spacing, hole orientation, sample recovery requirements, and rig type are all decisions that benefit from input from someone who has done the work before. You can get in touch with our team to talk through what you are planning, or read more about our consulting capability. Recent projects are described on our projects page, and the about us page covers our background.
