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DTH Drilling Machine Bit Wear? Reduce Cost 50% with Proper Selection & Operation

In mine blasting hole construction, drill bits are the most consumable wear parts – many mine operators report that drill bits need to be replaced on average every 3-5 days, resulting in high wear costs. Our Xinhao Drilling Rigs service to mining clients nationwide has found that 80% of excessive drill bit wear is not due to quality issues, but rather to mismatches between the geological formation and the drill bit selection, or improper operating parameters.

By mastering the core method of "selecting drill bits according to the geological formation + standardized operation," drill bit wear can be reduced by more than 50%. The following section provides practical techniques for handling common mining formations.

I. Different Mine Formations: Precise Drill Bit Selection is Key to Wear Prevention

The root cause of drill bit wear is "using the wrong drill bit against the wrong formation." Common mine formations such as hard rock, weathered rock, gravel layers, and soft rock require different types of down-the-hole drill bits. Specific matching solutions are as follows:

1. Hard Rock Formations (Granite, Basalt, hardness ≥ 8)

Wear Pain Points: The drill bit teeth come into direct contact with hard rock, easily resulting in tooth tip chipping and excessively rapid wear of the drill bit body.
Suitable Drill Bits: Select wide-pitch carbide ball-tooth drill bits (such as the Xinhao XH-Q320 model). The ball teeth are made of tungsten carbide alloy, increasing impact resistance by 40%. The wide pitch design distributes the force on each tooth, reducing wear.
Avoiding Common Mistakes: Avoid using ordinary alloy blade drill bits, as their tooth contact area is small, and the tooth tips will wear down within one day in hard rock.

2. Weathered Rock Formations (Sandstone and Shale weathering layers, hardness 3-5)

Abrasion Issues: Weathered rock is loose in texture, and rock powder easily enters between drill bit teeth, causing "abrasive wear" and leading to rapid thinning of the drill bit body.
Suitable Drill Bits: Select double-row wid

e-groove down-the-hole drill bits with a slag groove width ≥18mm to quickly remove rock powder and prevent powder from abrading the drill bit. Xinhao drill bits of this type also have a wear-resistant coating on the surface of the drill bit body, improving abrasion resistance by 30%.
Selection Tips: Avoid closely spaced drill bits, otherwise rock powder will clog the grooves, doubling the wear rate.

3. Gravelly Layers (Mining Blasting Zones, Fractured Zones)

Wear Issues: Gravel impacts the drill bit teeth and outer wall, causing tooth breakage and scratches on the drill bit's outer wall.

Suitable Drill Bits: Select thick-walled, impact-resistant down-the-hole drill bits with a wall thickness ≥12mm. The teeth feature an embedded design to prevent tooth loss due to gravel impact. Use Xinhao's custom-made drill bit protective sleeves to reduce outer wall wear.

Selection Tips: Avoid using thin-walled, lightweight drill bits, as they are easily deformed and worn through by gravel impacts. 4. Soft Rock Formations (Mudstone, Coal Seams, Hardness ≤ 2)
Wear Pain Points: Soft rock adheres to the drill bit, forming "mud pockets," causing drill bit slippage, friction between the teeth and mudstone leading to increased temperature, and accelerated aging of rubber seals.
Suitable Drill Bits: Select sparse-tooth diamond composite drill bits; the large tooth pitch makes them less prone to mud adhesion, and the diamond blades are wear-resistant and dissipate heat quickly.
Selection Avoidance: Avoid multi-tooth alloy drill bits, as they are easily clogged by soft rock, increasing ineffective wear.

II. Three Operating Techniques to Reduce Drill Bit Wear During Construction

Choosing the right drill bit is only the foundation; proper operating procedures can further extend drill bit life. The following three practical, field-tested techniques can reduce unnecessary wear by 50%:

1. Precisely Adjust Drilling Parameters to Avoid "Forceful Drilling"

Hard Rock Formations: Drill pressure controlled at 18-22kN, rotation speed 80-100r/min, air pressure 2.0-2.4MPa. High air pressure combined with low rotation speed reduces the friction time between the drill bit and the rock.
Weathered Rock/Gravel Layers: Drill pressure 12-15kN, rotation speed 100-120r/min, air pressure 1.8-2.0MPa. Quickly remove cuttings to prevent rock powder abrasion.

Soft rock formations: Drilling pressure 5-8kN, rotation speed 120-150r/min, air pressure 1.5-1.8MPa. Low pressure and high speed prevent the drill bit from getting buried in soft rock and forming a "mud bag". Xinhao DTH drilling rigs have a built-in parameter memory function, allowing preset parameters according to the formation, making it easy for even beginners to control precisely.

2. Adopting a "segmented drilling + hole cleaning" mode reduces ineffective wear

In mining construction, many operators try to speed things up by drilling "all the way to the bottom," leading to rock debris accumulation in the hole. Repeated grinding of the drill bit with the rock debris exacerbates wear.

Correct practice: After drilling 3-5 meters, stop drilling and open the high-pressure air hole cleaning system for 10-15 seconds to blow out the rock debris. When working in gravel layers, shorten the cleaning interval to once every 2 meters to prevent rock debris from grinding the drill bit at the source. 3. Conduct daily drill bit inspections and maintenance to prevent damage.

Before operation: Check for loose drill bit teeth and cracks in the bit body. Repair any minor damage by welding immediately to prevent small problems from escalating into overall wear. After operation: Clean the drill bit surface with high-pressure air to remove rock debris, apply special anti-rust lubricant, and store in a dry place to prevent the bit body from rusting and corroding. Important reminder: If the drill bit tooth tip wear exceeds 3mm, or the bit body thickness decreases by 20%, it must be replaced immediately. Continued use will lead to drill pressure imbalance and damage the drill rod.

III. Core Summary of Drill Bit Wear Control in Mining

The solution to rapid drill bit wear in down-the-hole (DHH) drilling rigs essentially boils down to "selecting the right drill bit for the geological formation and reducing friction during operation": hard rock relies on "impact-resistant drill bits + low pressure and low speed," weathered rock relies on "wide-groove drill bits + high-frequency hole cleaning," gravelly layers rely on "thick-walled drill bits + impact protection," and soft rock relies on "sparse-tooth drill bits + anti-mud packing."

Xinhao Drilling Rigs has developed a complete set of drill bit adaptation solutions for different geological formations in mines and provides operational training to customers. The average lifespan of drill bits in partner mines has been extended from 3 days to 7 days, directly halving wear costs. For mining construction, selecting the right drill bit and operating it correctly is far more cost-effective and efficient than frequently replacing drill bits.

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