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Terranox DTH Hammers

Terranox DTH hammers in use

Terranox - DTH Hammers for Geotechnical Applications

DTH drilling is gaining increased interest in geotechnical applications all around the world.

With advantages such as improved hole straightness and reliable performance in challenging ground conditions, this method is turning into the number one choice for many construction companies and well drillers.

Atlas Copco offers a wide range of geotechnical drilling equipment, and by introducing the Terranox DTH hammer we create a package with full focus on your application and your demands.

Sustainable Productivity

Challenges in urban development
Atlas Copco offers a wide range of high performing drilling equipment designed for percussive drilling. In fact, we offer the most productive DTH hammers in the world. DTH drilling as a method is growing in popularity in both foundation works and in well and geothermal drilling. As the global redevelopment of urban areas continues, this trend comes with a challenge - accessing and drilling in populated areas without damaging the existing structures around the work site. It is obvious that our customers in geotechnical operations have very different demands on the equipment than those working with high production drilling in, for example, quarrying. The demand for application-tailored solutions is increasing.

Low pressure drilling
In production drilling, especially in hard rock, the use of high pressure air is vital in order to flush the drill bit efficiently. In overburden ground conditions air from DTH drilling might unconsolidate the ground, decreasing the capacity of existing foundations. Construction companies and well drillers are frequently operating in urban areas where existing foundations are sensitive to any kind of disturbance in their immediate surroundings. In geotechnical applications lower air pressure (in the range of 12-18 bar) is therefore recommended. Focus is on reliable and safe operations along with minimal environmental impact.

With focus on your operations
With your operations in mind, we are now proud to present Terranox - a range of DTH hammers dedicated to cost-efficient and reliable geotechnical drilling. Terranox DTH hammers are designed for optimum performance in low pressure operations.

Terranox control panelReliable, well-proven technology
The Terranox hammer is based on well-proven technology and over 30 years of successful operations in the industry. When working in urban areas, drilling must usually be accomplished during restricted drilling hours. Reducing downtime is critical. Terranox hammers are rugged, reliable, and when damaged easily repaired or replaced. Together with Atlas Copco's worldwide service network, assuring availability of parts, services, and support, you can trust this cost-efficient product to do the job for you.

A dedicated package
Terranox DTH hammers are very well suited for use together with our well-proven casing advancement systems (Symmetrix, Odex and Elemex), Mustang drilling rigs, and Unigrout grouting equipment, all committed to reliable and safe geotechnical drilling. With Atlas Copco you get a unique in-house turnkey solution for your geotechnical drilling operation.

Terranox hammer

The Terranox product range
The Terranox DTH hammer comes in five sizes. Choosing the right hammer is largely determined by hole size and type of ground conditions.

Ideally the size of the hammer should match the required hole dimension as closely as possible, leaving just enough space for cuttings to evacuate the hole.

Terranox hammer range of sizes
Terranox DTH hammers
*shoulder to shoulder
Description / Part Number
Rec. Hole Size
Length Without Bit*
Weight Without Bit*
Terranox 3
8393 0826 35
API 2 3/8 Reg Pin
3 1/8
3 7/16 - 4 1/8
35 1/2
Terranox 4
8393 0826 40
API 2 3/8 Reg Box
3 5/8
4 1/8 - 5
41 5/16
Terranox 5
8393 0826 50
API 3 1/2 Reg Pin
4 1/2
5 1/8 - 6
45 7/8
Terranox 6
8393 0826 60
API 3 1/2 Reg Pin
5 3/8
6 - 8 1/2
49 7/16
Terranox 8
8393 0826 80
API 4 1/2 Reg Pin
7 1/8
7 7/8 - 10 5/8
56 13/16

Service and tuning kits
In abrasive drilling conditions, partially external components of DTH hammers are subject for excessive flush blasting and wearing out before the internal parts reach their fatigue limits. Wear often appears on the chuck itself or on the cylinder at the check-end. For this reason many Terranox hammers are designed with reversible cylinders. With help of defined service kits the hammers can be rebuilt and most internal parts reused for another run. Use of service kits extends the total hammer life and substantially reduces the total drilling cost, as the cost for service kits is only approximately 10% of a new hammer.

Terranox hammers are, for optimized drilling performance and hole cleaning, fitted with choke plugs to enable ultimate tuning of the hammer for each occasion and use. Replacement choke plugs are included in Terranox tuning kits.

For easy logistics, defined kits containing the vital parts are available for each hammer.


Click here for complete Terranox parts listings

A rule of thumb for use of service kits
Rock Formation
Hammer Life
Highly abrasive
<5000 m
Use service kit to rebuild the hammer 1-2 times
Medium abrasive
5000 - 10,000 m
Consider service kit to rebuild the hammer 1 time
None abrasive
>10,000 m
Rebuilding not recommended, risk that internal parts might fail before the service kit is worn out

Matching hammer and casing diameterMatching hammer and casing diameter
For proper selection of Terranox hammer to match casing diameter, please use the cross-reference table below. Casing size and drilling conditions will be decisive factors when selecting a casing advancement system.

Hammer Description
Casing Diameter Range (inch)
Terranox 3
4 1/2
Terranox 4
5 1/2 - 6
Terranox 5
6 5/8 - 7
Terranox 6
7 5/8 - 9 5/8
Terranox 8
9 5/8 - 12 3/4

Selecting compressor capacity
The Terranox hammer range is designed for a maximum working pressure of 25 bar. In overburden drilling applications air pressure is normally recommended to be kept in the range of 12-14 bars. However, for proper hammer performance throughout the entire drilling operation the compressor model should be selected to match the corresponding maximum hammer air consumption, shown below.

Hammer Description
Air Consumption (at 24.1 bar) (scfm)
Terranox 3
Terranox 4
Terranox 5
Terranox 6
Terranox 8

Above specifications/ratings are based on initial factory setting.

Drill rig requirements
For proper hammer performance the geotechnical drilling rig should be equipped with a rotation unit providing minimum torque, as per the table shown below.

Hammer Description
Minimum Torque (lb. ft.)
Terranox 3
Terranox 4
Terranox 5
Terranox 6
Terranox 8

A complete package from Atlas Copco

Casing advancement systems
Atlas Copco offers three casing advancement systems: Symmetrix, Elemex, and Odex. With these systems a casing pipe is installed simultaneously as the hole is drilled. The casing prevents the hole from collapsing. Using an Atlas Copco casing advancement system is particularly advantageous for foundation works or well drilling in urban areas. These systems offer high productivity even if the ground contains boulders, concrete blocks, or old foundations that are hard to penetrate; and they can easily drill a rock socket into the bedrock if required. When used for micropiling, cased piles can accommodate large load concentrations also from lateral forces.

The drilling principle is based on a pilot bit and a reamer bit, which together drill a hole larger than the external diameter of the steel casing. This enables the casing pipe to follow the drill bits down the hole. Odex has an eccentric reamer bit, while Symmetrix and Elemex feature a concentric reamer called a ring bit.

The concentric drill bit design gives Symmetrix plenty of benefits: incomparable hole straightness, deep drilling capability, and incredibly quick pile setting. Symmetrix is an ideal tool for all kinds of ground conditions and superior when there are big obstacles in the ground or sloping bedrock exists. For well drilling, the Symmetrix range offers drill-through systems. When the surface portion is cased and sealed in the overburden layer, the pilot bit can drill further into the bedrock without having to change drilling equipment. Symmetrix is also capable for all types of micropiling work whether there is an end-bearing or friction pile to be drilled.
The Elemex system design is based on the Symmetrix concentric system, but is especially designed for DTH drilling in urban areas or sensitive ground. The unique concept behind the Elemex design is built on redirection of air flow. Once the air reaches the bit face, it is blown against the extended ring bit walls, which redirect the flow across the face. This way the air pressure is decreased just enough to allow an efficient flushing of the bit face without escaping to the surrounding ground. Elemex is gentle on the surrounding ground, but tough on the boulders that might come in its way.
Odex Odex
The eccentric retrievable Odex system is ideal for short holes up to 10 3/4" in diameter. Well drillers often have an Odex drill bit at hand for simultaneous casing of water and geothermal wells. Odex offers quick and cost-efficient drilling. When a casing has been installed, the complete drill bit is retrieved - ready to drill the next hole. The Odex system was originally developed, in the late 1960s, as a reliable method for micropiling with steel core piles, as is today still very popular when drilling in basic ground conditions.

Mustang geotechnical drilling rigs
Unigrout grouting platforms

Mustang geotechnical drilling rigs
The Mustang geotechnical drilling rings from Atlas Copco offer a flexible concept for drilling, well suited for most drilling methods on the market, DTH drilling being one of them. The Mustang range is based on four families - the Mustang 4, 5, 9, and 13. Each family has been designed for a range of uses and environments, based on many years of experience. We use standard modular components - feeds, rotary heads, boom systems, and basic frames - all of which can be combined on a large variety of carriers.

In low access areas and confined spaces, the flexible and compact Mustang rigs offer high performing solutions. Thanks to its modular design, the Mustang rig not only handles micropiling, slope stabilization, and well drilling, it can be your partner of choice in basically all geotechnical drilling operations. This flexibility of use provides a unique possibility to optimize your operations and keep lifetime costs low.

Unigrout grouting platforms
The Atlas Copco Unigrout range offers a range of grout systems designed to seal, strengthen, or consolidate formations and structures by preparing and injecting grout. The platforms are operated by fully hydraulic power units, with electric or diesel drive.

For urban applications the Unigrout range provides a set of very compact, high performance grouting units that are safe to operate, highly reliable, and easy to clean and service.

In micropiling operations controlling grouting parameters is a must. For a full monitoring of grouting treatment the Logac electronic grout recorder can be added on to the original design or at a later stage.

Secoroc drill bits
Atlas Copco compressors
Secoroc drill bits
In geotechnical applications and in combination with Atlas Copco's casing advancement systems, Secoroc drill bits are especially suitable for continuous drilling in homogeneous formations. Atlas Copco Secoroc offers a wide selection of bit head designs suitable for different rock formations.
Atlas Copco compressors
Atlas Copco is the leading manufacturer of portable compressed air machines in the world. Used in a wide variety of industries, Atlas Copco has developed a set of machines that successfully walks the line between size, output, and capacity.