The challenges drillers face when drilling in mines and quarries are well documented the world over. Drilling in fractured rock; what to do with an uneven rock floor following a blast; holes that collapse due to an influx of water; heavily fractured rock that eventually collapses; filling a hole, partly or completely, with explosives. Sounds familiar?
With DTH drilling becoming the preferred method in foundation works, well and geothermal drilling, TerraRoc offers a wide range of high-performance equipment for these sensitive and challenging areas.
Terranox DTH hammers are designed for optimum performance in low pressure operations. 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 often be accomplished during restricted drilling hours. Reducing down time is critical. Terranox hammers are rugged, reliable and, when damaged, easily repaired or replaced. Together with TerraRoc’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
The Terranox DTH hammers are designed to work with our well proven casing advancement systems: Symmetrix, Elemex and Odex. Together they form a unique in-house turnkey solution for your geotechnical drilling operation, offering reliable and safe geotechnical drilling.
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 DTH hammers | |||||||||||
| Description | Thread Connection | Outside diameter | Rec. hole size | Shank Style | Length without bit | Weight without bit | Part number | ||||
| mm | inch | mm | inch | mm | inch | mm | inch | ||||
| Terranox 3 | API 2 3/8 Reg PIN | 79 | 3 1/8 | 88 - 105 | 3 7/16 - 4 1/8 | DND | 902 | 35 1/2 | 30 | 66 | 8393082635 |
| Terranox 4 | API 2 3/8 Reg BOX | 92 | 3 5/8 | 105 - 127 | 4 1/8 - 5 | DND | 1049 | 41 5/16 | 39 | 86 | 8393082640 |
| Terranox 5 | API 3 1/2 Reg PIN | 115 | 4 1/2 | 130 - 152 | 5 1/8 - 6 | DND | 1166 | 45 7/8 | 69 | 152 | 8393082650 |
| Terranox 6 | API 3 1/2 Reg PIN | 137 | 5 3/8 | 152 - 216 | 6 - 8 1/2 | DND | 1255 | 49 7/16 | 103 | 227 | 8393082660 |
| Terranox 8 | API 4 1/2 Reg PIN | 181 | 7 1/8 | 200 / 270 | 7 7/8 - 10 5/8 | DND | 1443 | 56 13/16 | 177 | 390 | 8393082680 |
Service and tuning kits
In abrasive drilling conditions, partly external components of the DTH hammers are subject for excessive flush blasting and is wearing out before the internal parts reaches their fatigue limits. Wear often appears on the chuck itself or on the cylinder at the chuck-end. For this reason, many of the Terranox hammers are designed with reversible cylinders.
With help of defined service kits, the hammers can be rebuilt, and most internal parts re-used 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 service and tuning kits | |||
| Description | Part number | ||
| Hammer | Service kit | Tuning kit | |
| Terranox 3 | 8393082635 | 8393082723 | 8393082728 |
| Terranox 4 | 8393082640 | 8393082724 | 8393082729 |
| Terranox 5 | 8393082650 | 8393082725 | 8393082730 |
| Terranox 6 | 8393082660 | 8393082726 | 8393082731 |
| Terranox 8 | 8393082680 | 8393082727 | 8393082732 |
| A rule of thumb for use of service kits | ||
| Rock formation | Hammer life | Action |
| Highly abrasive | < 5,000m | Use service kit to rebuild the hammer 1-2 times |
| Medium abrasive | 5,000 - 10,000m | Consider service kit to rebuild the hammer 1 time |
| None abrasive | > 10,000m | Rebuilding not recommended, risk that internal parts might fail before the service kit is worn out |
Terranox hammers are, for optimized drilling performance and hole cleaning, fitted with choke plugs to enable an ultimate tuning of the hammer for each occasion and use. Replacement choke plugs are included in the Terranox tuning kits.
For easy logistics defined kits containing the vital parts are available for each hammer as to below table.
Matching hammer and casing diameter
For proper selection of Terranox hammer to match casing diameter, please use cross reference table below. Casing size and drilling conditions will be decisive factors when selecting casing advancement system.
| Hammer description | Casing diameter range | |
| mm | inch | |
| Terranox 3 | 114.3 | 4 1/2 |
| Terranox 4 | 139.7 - 152.4 | 5 1/2 - 6 |
| Terranox 5 | 168.3 - 177.8 | 6 5/8 - 7 |
| Terranox 6 | 193.7 - 244.5 | 7 5/8 - 9 5/8 |
| Terranox 8 | 244.5 - 323.9 | 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 the 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) | |
| l/s | scfm | |
| Terranox 3 | 239 | 506 |
| Terranox 4 | 292 | 618 |
| Terranox 5 | 358 | 760 |
| Terranox 6 | 459 | 973 |
| Terranox 8 | 725 | 1538 |
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 | |
| Nm | lb ft | |
| Terranox 3 | 600 | 440 |
| Terranox 4 | 1500 | 1020 |
| Terranox 5 | 2000 | 1480 |
| Terranox 6 | 3000 | 2210 |
| Terranox 8 | 8000 | 5900 |