Top Hammer Drilling Rig VS DTH Drilling Rig, What are ... - JK Drilling

Drilling is an important part of mining mines. The equipment used is mainly the top hammer drilling rig or DTH drilling rig. These two are suitable for different mining operations, and the wrong use will cause huge losses. If you want to know the difference between these two rigs, keep reading.

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Different Working Principle

Operation Schematic Diagram(a: top hammer drilling rig; b: DTH drilling rig)

Top Hammer Drilling Rig

The impact force of the top hammer drilling generated by the piston of the pump in the hydraulic drilling rig is transmitted to the drill bit through the shank joint and the drill rod, which is the most different from the down-the-hole drill. At the same time, the percussion system drives the drilling system to rotate. When the stress wave reaches the drill bit, the energy is transferred to the rock in the form of penetration by the drill bit. The combination of these functions can drill holes in hard rock.

However, top hammer drilling is usually used for the maximum diameter of 127mm, and the depth of the hole is less than 20M, which has high efficiency.

In Top Hammer Drilling the hammer produces a percussive force on the drill rods or tubes, which is transmitted to the drill bit. The feed device is usually attached with a hinged boom to a mobile unit. The percussive system strikes the drill rod, for example 2,000-5,000 strikes per minute, and the rotation speed can be, for example, 60-200 rounds per minute. Together these elements make it possible to drill holes in the hard rock. The excess material (cuttings) is flushed up from the bottom of the hole by means of pressurized air or water. Top hammer drills are primarily used in mining, construction and quarrying of rock material. Top hammer drilling, combined with the “drill and blast” method, makes the whole excavation process extremely efficient.

DTH Drilling Rig

The down-the-hole drill uses compressed air to drive the hammer behind the drill bit through the drill rod. The piston directly hits the drill bit, and the hammer cylinder provides a straight and stable guide for the drill bit. This keeps the effects of energy from being lost in the joints and allows deeper percussion drilling.

In addition, the impact force acts on the rock at the bottom of the hole, which is more effective and straighter than other drilling operations.

DPH drilling is more suitable for large holes in hard rock drilling, especially for rocks with a hardness of more than 200Mpa. However, for rocks below 200 MPa, not only energy will be wasted, but also the drilling efficiency will be low, which will cause serious wear on the drill bit. This is because when the hammer's piston strikes, the soft rock cannot fully absorb the impact, which severely reduces the efficiency of drilling and slagging.

In DTH drilling, the percussion mechanism – commonly called the hammer – is located directly above the drill bit. The drill pipes transmit the necessary feed force and rotation to the hammer and the bit, along with the fluid (air, water or drilling mud) used to actuate the hammer and flush the cuttings. The drill pipes are added to the drill string successively behind the hammer as the hole gets deeper.

The hammer is fully fluid actuated. It is composed of two mobile parts: a valve, controlling the flow and a piston that strikes on an impact surface directly linked to the bit. The hammer body gives straight and stable guidance of the drill bit.

Differences of Adaption 

JK410 Crawler Mounted Pneumatic Tophammer Drill Rig

Top Hammer Drilling Rig

ㆍThe most suitable for hole diameter between 25–127 mm.

ㆍGenerally, the hole depth is less than 25 meters.

ㆍAdapt to a stable and uniform hard rock.

ㆍThe slag flushing medium is compressed air or water.

ㆍHigh efficiency in shallow holes drilling, the deeper the lower efficiency.

JK650 All In One DTH Drilling Rig

Down the Hole (DTH) Drilling Rig

For more information, please visit DTH Drill Bits.

ㆍThe most suitable hole diameter is 100–254 mm, in special applications can be up to 2M And the minimum can be around 50 mm as well.

ㆍTheoretically drilling depth is limited by back pressure only (can be up to several kilometers).

ㆍAdapt to hard rock and rock formation conditions (compared to top hammer).

ㆍMainly use pressurized air for slag flushing, and sometimes air foam for special application.

ㆍHighly efficient in hard rock drilling.

In summary, each drilling rig has its own advantages. When choosing the equipment, you can first look at the actual situation of your project, and decide which type of rig to choose according to the rock formations, geological formations, and working environment of the construction site.

JK Drilling is a large enterprise specialized in the development and manufacture of all kinds of DTH Drilling Equipment. The major products include All-In-One type and separate type DTH rock drilling rigs, DTH well-drilling rigs, and construction drilling rigs. 

Top hammer drilling rigs are essential tools in the mining and construction industries, known for their efficiency and effectiveness in drilling operations. These rigs utilize a unique mechanism that combines the power of a hammer with the drilling process, making them ideal for various applications.

Top hammer drilling rigs are designed to deliver high-impact energy to the drill bit from the top of the drill string. This is achieved through a series of components, including a hydraulic or pneumatic hammer, drill rods, and a drill bit. The hammer strikes the drill bit, creating a rapid succession of impacts that break the rock, allowing for efficient penetration.

Key Features of Top Hammer Drilling Rigs

1. High Penetration Rate : One of the most significant advantages of top hammer drilling rigs is their ability to achieve high penetration rates. The impact mechanism allows for quick and effective drilling, making them suitable for various geological conditions.

2. Versatility  :Top hammer rigs can be used for a wide range of applications, including exploration drilling, production drilling, and construction projects. They are effective in both soft and hard rock formations.

3. Mobility : Many top hammer drilling rigs are designed to be mobile, allowing them to be easily transported to different job sites. This flexibility is particularly beneficial in remote locations or where access is limited.

4. Cost-Effectiveness ue to their efficiency and speed, top hammer drilling rigs can help reduce overall project costs. Faster drilling means less time spent on-site, which can lead to significant savings in labor and equipment rental.

5. Improved Safety : Modern top hammer drilling rigs are equipped with advanced safety features that minimize risks for operators. Automated systems and remote control capabilities enhance safety and reduce the need for manual intervention.

Top hammer drilling rigs are widely used in various industries, including:

Mining: These rigs are crucial for mineral exploration and extraction, allowing miners to drill blast holes efficiently.

Construction: In construction, top hammer rigs are used for foundation drilling, rock excavation, and other earthworks.

Geotechnical Engineering: They are employed in geotechnical investigations to obtain soil and rock samples for analysis.

Top hammer drilling rigs are powerful and versatile tools that play a vital role in various drilling applications. Their high penetration rates, mobility, and cost-effectiveness make them a preferred choice for many industries. As technology continues to advance, we can expect further improvements in the efficiency and safety of top hammer drilling rigs, solidifying their importance in the future of drilling operations.