If you need equipment that moves quickly, handles rough terrain, and drills blast holes steadily, the DTH drilling machine is an ideal choice for mines, quarries, and earthworks. Both YG412 and YG420 are diesel-powered crawler drills. They support drilling at any angle from 0° to 90° and meet different hole diameter and depth requirements. Send us your rock hardness, hole diameter, hole depth, and project location, and you will get a suitable model recommendation and DTH machine price.
A DTH drilling machine is a percussive-rotary drilling machine. Unlike traditional top hammer drills, its hammer sits at the end of the drill pipe close to the bit, generating impact energy directly at the bottom of the hole.
This design cuts energy loss during transmission along the drill string. It improves drilling efficiency and keeps deeper blast holes straighter with a more stable hole diameter. For this reason, it works very well for hard rock, abrasive formations, and blast holes with large diameters.
How does a Down the Hole Drilling Machine Work?
The down the hole drilling machine carries out three actions at the drill bit at the same time:
1. Percussion – powered by the down-the-hole hammer.
Compressed air drives the piston inside the hammer, striking the top of the bit at high frequency. Since the hammer sits right behind the bit, nearly all impact energy goes into the rock. YG412 comes with a 3.5″ hammer and YG420 comes with a 4″ hammer.
2. Rotation – powered by the rotary head.
The rotary head slowly turns the drill pipe, repositioning the bit onto fresh rock between impacts. YG412 delivers 1,650 N·m rotation torque while YG420 delivers 2,200 N·m — higher torque matches larger bits and hammers. Rotation speed follows the same logic. YG412 runs at 100–220 rpm, and YG420 runs at 0–150 rpm. Larger hammers run slower. In DTH drilling, rock breaks from impact instead of cutting. Rotation only repositions the bit. A bigger hammer delivers stronger single blows and needs more time for the bit to reset.
3. Cuttings removal – using exhaust air.
The same compressed air that drives the piston flows through the bit and exits at the hole bottom. It carries rock cuttings up the annular space around the drill pipe out of the hole. Continuous flushing prevents the bit from regrinding broken rock debris.
The DTH drilling machine is widely used by mines, quarries, and construction contractors because it combines mobility, high drilling efficiency, and good adaptability to difficult ground.
Fast relocation: The crawler undercarriage allows quick movement between working positions.
High drilling efficiency: The hammer works downhole for direct energy transfer, ideal for medium-hard and hard rock.
Flexible drilling angles: Drills at any angle from 0° to 90°, including horizontal holes.
Good rough-terrain performance: 25° gradeability and 2.5 km/h travel speed suit mines and uneven sites.
Diesel power: No reliance on site power supply, perfect for remote mines and field projects.
Built for blast holes: Widely used to drill blast holes in open-pit mines, quarries, and other surface works.
Application Scenarios of the Down the Hole Drilling Machine
A DTH drilling rig is used wherever blast holes need to be drilled into rock at set angles and depths. The YG series fits:
Metallurgy & Mining
Open-pit blast hole drilling in metal mines and quarries — the main application of this type of equipment.
Building Materials
Drilling for limestone, sandstone and aggregate quarries to support the construction materials industry.
Railway Construction
Rock excavation and blast hole drilling for cuttings, tunnel portals and subgrade works.
Hydropower Projects
Rock excavation, slope stabilization, and foundation blast holes for dams and water conveyance projects.
National Defense Works
Rock excavation projects requiring blast hole drilling.
Earthworks & Open-air Projects
Blast hole drilling for site leveling, road construction, and other rock-breaking works.
Underwater Drilling & Reef Blasting
Both models are also suitable for underwater drilling and reef blasting.
Price depends not only on the drill itself, but also on configuration, wear parts, shipping method, and after-sales service. When sourcing, do not compare bare machine quotes only. Evaluate the total investment and long-term operating cost of the full drilling package.
Main factors affecting DTH machine price:
Drilling capacity: Larger hole diameter, deeper holes, and harder rock usually require higher-spec drill rigs, hammers, and air compressors.
Air compressor matching: DTH drilling needs stable air pressure for impact and cuttings removal. Undersized compressors slow drilling and speed up bit wear.
Power and hydraulic setup: Diesel engine power, hydraulic capacity, and chassis design affect machine performance and purchase cost.
Included accessories: Whether drill pipes, hammers, bits, lubrication units, and common spares are included directly changes the total price.
Shipping & import costs: Ocean freight, insurance, destination charges, customs duties, and inland transport should all be included in your budget.
After-sales support: Spare parts supply, technical guidance, warranty, and operator training affect downtime and total cost of ownership.
From a purchasing perspective, evaluate projects by total cost per drilled meter instead of machine price alone. Fuel consumption, compressor efficiency, bit and hammer wear, labor, maintenance, and downtime losses all shape your actual project cost.
Q1: Can a DTH drilling machine drill horizontal holes?
Yes. Both models drill at any angle between 0° and 90°, including horizontal holes. You must secure the rig properly to keep operations safe. For horizontal and steep-angle drilling, the limiting factor is rig stability rather than drilling capability.
Q2: How long does a hammer last?
About one week with 8 hours of operation per day.
Q3: What is the service life of a drill bit?
Around 3 days with 8 hours of operation per day.
Q4: What is the drilling speed?
20 to 30 meters per hour. Actual speed depends on ground conditions. Harder, more abrasive rock brings the rate toward the lower end.
Q5: How does the rig move between hole positions?
It travels on its crawler chassis at 2.5 km/h, with 25° gradeability, 310 mm ground clearance and 40 kN traction force. The YG420 additionally has ±10° crawler frame oscillation to adapt to uneven ground.
Get Your Down the Hole Drilling Machine Quotation
A properly configured down the hole drilling machine helps mining and engineering customers boost blast hole productivity, cut relocation time, and handle tough rock drilling conditions. Choose YG412 for medium or softer rock formations, or YG420 for harder rock and larger holes. Model selection should match your actual geology and project requirements.
To get customized recommendations and DTH machine price, please provide the information below:
Rock type and hardness
Required hole diameter
Required hole depth
Project country or region
Whether you need drill pipes, hammers, bits, or spare parts
Our team will prepare a suitable equipment configuration plan based on your working conditions.
