Mobile PlantSafetyTechnical Services

The deepest underground exploration holes !

5 Mins read

Swick continue to push the envelope in both performance and output from their Perth built underground drill rigs. The DeepEx division provides specialist rigs that can deliver some of the deepest underground diamond drill holes globally, which has now been proven across several clients sites in Australia and Europe. Reducing costs for clients and saving time for geologists defining deep and complex resources.

Established in 2019 by Swick to undertake their clients’ deep and complex drilling requirements, the DeepEX division and its specialised team have operated in varying rock types and ground conditions. Their market share has continued to grow by focusing on safety, high performance, high production and capitalising on market reputation.

After continued requests for deeper drilling from underground platforms, Swick quickly came to the realisation that their high-performance Gen II mobile drill rig would exceed its productive range limit and no longer be cost effective when drilling deeper projects. Swick delivers beyond just drilling, with in-house capabilities of research and manufacturing for our customer base. We subsequently developed a unique, high capacity, mobile solution for deep and underground exploration drilling.

The DeepEX division provides opportunity for underground projects to drill deep exploration diamond drill holes from better approach angles from existing underground platforms. With shorter length holes and lower operating costs, the end results for clients are significantly lower costs per metre than drilling from the surface.  

Clients are utilising DeepEX to target outside of known existing mineralisation envelopes, beyond the capability of standard underground drill rigs. Allowing important geological information to be efficiently collected and interpreted into models well ahead of the mining front.

Swick’s unique DeepEX rigs are fitted with a high-powered feed frame on a large mobile carrier base, allowing for deep exploration and high torque drilling from any standard underground drill location. The high-capacity feed frame can accommodate deep directional exploration holes that exceed 2,000m of NQ2 core and approximately 3,000m of BQ. Another advantage of DeepEX rigs is the ability to complete larger diameter holes with capabilities of PQ (122.6mm diameter), allowing for mine infrastructure drilling to depths of 500m. Having the capability to drill PQ offers a dual use for rigs based at a particular project. Additionally this ability de-risks projects as opposed to other methods adopted by drill contractors such as back reaming or down-hole hammer, which are prone to downhole deviation.

The versatility continues with drilling of steep upholes angles to vertical down holes, allowing for many drill holes to be collared from one location. In many cases drill target intercepts can be achieved from an underground location with less complication, effort and cost than from the surface.  Clients are benefitting from utilizing DeepEX by reducing the reliance on surface drilling; eliminating environmental disturbance, the costs associated with drill pads, access roads, water cartage, fuel costs, permitting and rehabilitation.

Innovation and industry expertise has allowed DeepEx to deliver maximum productivity and reduce risks for those exploring from deep underground. Source: Swick

Generally, underground diamond drill rig rod handling systems require the operator to load a drill rod into the machine manually. In contrast, DeepEX rigs utilise a unique and fully mechanised ‘hands off steel’ rod handling system. This system allows an operator to pick up a rod or inner tube effortlessly using a lift augmentation device (L.A.D) and place it into a rod presenter without the need to bear the rod’s weight. This substantially reduces operator fatigue and mitigates many hazards associated with rod handling while significantly reducing operators’ risk of personal injury.

The dual rod handling system enables a drill assistant (Offsider / Helper) to remove or add thousands of meters of rods to the drill with minimal effort and risk. The system allows for rod handling of all sizes of drill rods from BQ to PQ size, from 1.5 metre (5′) to 3 metre (10′) lengths.

Core recovery can be produced quickly and efficiently at depths beyond 2000m while orientation and presentation remain paramount. DeepEX has proven to be successful for hole completion, hitting all targets within the required spacing, drilling through heavily faulted and sheared host rock. As of March 2022, the DeepEX team has drilled over 75kms (46 miles) of core, without leaving any drill string or casing in the ground.

Innovation continues in project planning, as the DeepEX team use advanced software from Landmark (Halliburton) to plan and execute deep, complex exploration holes in-house. This delivers the ability to plan navigational work and wedging operations, taking away the need for a geologist to design and project hole deviation. The site geologists supply coordinates for their proposed target by giving DeepEX a target Easting, Northing, and depth from the surface.

The coordinates are uploaded into the software, calculating the starting dip inclinations and azimuth to best suit the target and build a drill hole to meet each target point. The software has multiple methods of achieving the desired target, with either straight or curved designed holes allowing for options to de-risk the drilling.

The Swick DeepEX underground drill rig fleet, now proven to be able to drill >2000 meters from underground platforms. Source: Swick

A recent hole completed for a client in Western Australia showcased an outstanding performance completing a 1,500m hole in 56 productive shifts with a 26.8m drilled per shift. Production like this has never been achieved for the duration of a hole to this depth with an underground diamond drill rig. Another standout example of operational excellence came from a rig operating within South Australia recently completing the deepest hole on record, to a depth of 2,254m. The drill hole began with HQ and was stepped down to NQ and finally finished the tail with BQ sized drill rods, hitting the required target spacing.

DeepEX is currently operating at a third site in Western Australia, known to host some of Australia’s most challenging drilling conditions. On this site the team have faced many challenges, encountering pressurized ground within sheared horizons serpentinised ultramafic resulting in large amounts of cave-in material presenting in core. The pressurization within the ultramafic that is experienced is a direct result of this volume expansion, as drill holes advance, the ground is immediately moving to equalize the sudden pressure differential between the rock mass and open hole. This inhibits the retrieval of tubes and often results in excessive reaming to return to thebottom of hole following tube retrieval and shift changes. Maintaining hole annulus is essential to combating pressurised ground and removal of cuttings from the bottom of the hole. These shear zones are also conduits for large volumes of meteoric water that severely inhibits the effectiveness of grouting. Other methods have been successfully deployed, eliminating grouting as commonly and unsuccessfully adopted by other drill contractors.

With the high torque and power produced from DeepEX, advancing through shear zones, the team understands the importance of having the right plan in place and ability to execute, in conjunction with advanced drill fluids and experienced operators is essential for continued success.

DeepEX rigs utilise a purpose-built mud mixing and recycling unit allowing for high quality drilling fluids to be maintained, 70% of which is recycled which greatly reduces wastewater and the associated drilling fluid costs to the client.

The combination of highly experienced teams, high-quality training, powerful rigs, and a unique rod handling system streamlines operations making DeepEX an industry leader in underground exploration drilling. Swick’s DeepEX division is the solution for your underground deep exploration and infrastructure drilling requirements.

More information on Swick’s services can be found at:

Thanks to Rob Burnett, Swick Business Development Manager for his input on this article.

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