A skilled operator should always be aware of the soil or rock type and its strength during drilling. Choosing the right drill rod, drilling tool, and drilling method is crucial for efficient operation, minimal wear, lower load, and maximum drilling speed.

Based on ground conditions, rotary drilling rigs generally use four main drilling methods: cutting, crushing, scraping, and grinding.

1. Cutting Method

In cutting drilling, bucket teeth and a double-bottom sand bucket are used with a friction Kelly bar. This method works well in soft, low-resistance layers with an unconfined compressive strength up to about 400 kPa, such as clay, silt, or sandy soils. The bucket teeth rotate to cut through the material, reducing resistance and increasing drilling speed.

2. Crushing Method

The crushing method uses pick teeth and a double-bottom rock bucket. Depending on the ground strength, either a friction Kelly bar or a locking Kelly bar can be used. This method is suitable for harder formations with a strength of 500–1000 kPa, such as gravel layers, mudstone, sandstone, shale, or moderately weathered rock. Additional crowd force is applied, and the pick teeth break the material through the carbide tips.

3. Scraping Method

The scraping method can be used with either a double-bottom sand bucket or a double-bottom rock bucket fitted with special teeth. This method is ideal for formations like cobble layers, where pebbles are irregularly arranged and cannot be easily cut or crushed. The operator lifts the drill rod using the main winch and gently scrapes or loosens the cobbles with the bucket teeth. Once the material is loosened, the bucket is lowered to collect it. This reduces the impact force and avoids excessive vibration.

4. Grinding Method

The grinding method uses rock core barrels and roller bits together with a locking Kelly bar. It is suitable for rock layers with uniaxial compressive strengths ranging from a few MPa to several tens of MPa, typically for end-bearing rock-socketed piles. A core barrel cuts and grinds into the rock by ring cutting, or a roller bit grinds the rock surface. Depending on the rock’s strength, brittleness, and fractures, some crushing may also occur during this process.

Summary

By selecting the appropriate drilling method according to geological conditions, operators can work more safely and efficiently, extending the equipment’s life and improving overall project quality.

Over the years, Doosan has released quite a few new models — from the toy-sized DX20Z to the giant DX1000 you have to look up at. But when it comes to real classics, their 20–30 ton class excavators are still the go-to choice. Today, I’ll share my experience with the DX270LC-9C.

Background

The DX270 is an upgraded version of the older DX260LC-9C. For those familiar with Doosan’s -9C series, you’ll know they’ve always been solid performers. So how does the upgraded 270 hold up?

I mostly do earthwork and rock excavation, and the 270’s positioning is just right for my projects. Ever since I started in this business, I’ve used Daewoo and Doosan’s old 300H and the later -9C series. Never had any major breakdowns — so I trust Doosan’s machines and honestly, I’m just used to them. When it came time to add a 27-ton machine to my fleet, going with Doosan again was a no-brainer.

Impressions

Just look at that familiar Doosan orange — I’ve gotten used to seeing it all these years. Sure, it gets dirty quickly on site, but every time I wash it and see it gleaming under the sun, it really lifts my mood. The more I look at it, the more I like it.

The engine? Nothing much to say — it’s Doosan’s six-cylinder paired with premium imported key components. Just use it and don’t worry about it.

The 1.5 cubic meter bucket is more than enough. It breaks ground fast and loads trucks quickly. On site, smart operators always pick the 270 for loading because it’s so efficient. The sales rep mentioned that the 270 uses the latest electronically controlled hydraulic system — I don’t know the technical details, but in practice, it’s super smooth and noticeably more fuel-efficient. Plus, Doosan’s own power optimization and smart control really do save fuel without sacrificing performance.

One Year In

I’ve been running it for almost a year now — so far, zero issues. It’s classic Doosan style through and through, though I guess we’ll have to get used to calling it Diwanlon from now on. But honestly, I don’t care what it’s called — as long as they build solid machines that make money for us operators, I’ll keep buying them.

To Fellow Earthwork Operators

For those of you also working in earthmoving, what machines are you running? Let’s share some experiences! Wishing everyone good business and good vibes out there — may we all prosper!

Here’s a quick comparison of 10 popular 6-ton class mini excavators:
Doosan DX60-9C, Kobelco SK60-8, Hyundai HX60, Caterpillar Next Gen 306, Komatsu PC60-8, Hitachi ZX60-5A, SANY SY60C, XCMG XE60DA, Liugong CLG906D, and Volvo EC60D.

Doosan DX60-9C

The DX60-9C is slightly slower but operates smoothly. The bucket is a bit small but digging force is relatively strong, and fuel consumption is average. It’s one of the few models not using a Yanmar engine — instead, it has a slightly higher power output. The cab is very comfortable with ample legroom. However, the steel quality could be better and undercarriage parts are not very durable. Overall detailing still needs improvement. It has excellent breaker capability, making it suitable for hammering work. In summary: strong digging force, fast swing, good for hammering, slightly slower movements, thinner steel plates, more minor issues, but relatively affordable.

Kobelco SK60-8

The SK60 is fast, with the quickest swing speed in this group. It’s fuel-efficient and does a good job for earthmoving tasks, with a moderate bucket size. It uses a Yanmar 94 engine with lower power and displacement, so it lacks power and has weak travel force. The cab is smaller and less comfortable than Doosan’s. The undercarriage is decent and the steel quality is among the better ones in this list. Overall, it’s cost-effective for hourly rental work and general earthmoving but not ideal for heavy-duty tasks. It has acceptable quality but tends to develop small issues over time.

Hyundai HX60

The new Hyundai uses an imported Yanmar 94 engine. The bucket is small, swing is slow, but travel speed is good and fuel consumption is low. It’s prone to minor problems but comes at a reasonable price. The cab is well-finished and comfortable. Good for hammering work. Overall: affordable, good speed, hammer-friendly, decent for daily rental.

Caterpillar Next Gen 306

The new 306 is powered by Caterpillar’s own C2.4 engine — the lowest power output among these ten. Fuel consumption is lower than the old version, but so is digging force. Travel speed is the fastest, even quicker than the Kobelco. It has a bulky rear end, making it prone to bumps and scratches. It features lots of advanced tech, a high-end cab, but has complex wiring which can be troublesome when repairs are needed. Best suited for light-duty tasks and rental work.

Komatsu PC60-8

One of the toughest machines in this group. It has a large bucket, comfortable operation, heavy weight, high power, and strong digging force — all translating to high work efficiency. The undercarriage is very durable. It’s great in almost every aspect except fuel consumption: it’s a gas guzzler, even higher than the SANY 75. In summary: very durable, few minor issues, high work efficiency, but very thirsty for fuel and on the expensive side.

Hitachi ZX60-5A

Has the highest engine power among these ten, relatively quick, quite fuel-efficient, and a larger bucket. Digging force is not as strong as the Komatsu. The cab is clear, user-friendly, and comfortable. The undercarriage sits low and small, making it prone to getting stuck. Compared to the older model, it’s slightly slower but with a nicer cab. Some reports of cylinder noise and a few minor issues on new units.

SANY SY60C

Fast, fuel-efficient, but movement coordination is not very smooth. Digging force is moderate, travel force is weak, and undercarriage parts wear out quickly. The engine may emit black smoke and has its share of small problems, especially with the undercarriage. However, it has the largest fuel tank, which is a plus. Overall: good for hourly rental and earthwork, well-priced.

XCMG XE60DA

The new XCMG’s performance is quite average. The design has some issues: no major failures but frequent minor problems. Movements are so-so, fuel consumption isn’t low, but pricing is attractive.

Liugong CLG906D

Decent digging force, but the fuel tank is quite small — only about 100 liters. Overall good for a domestic model. Travel speed is acceptable, bucket is slightly large, swing is not slow. Pricing is reasonable, though still behind joint ventures in overall refinement. Some small issues but no major flaws.

Volvo EC60D

Fast swing and quick compound action. Fuel-efficient, bucket size is moderate at about 0.23 m³. Digging force is similar to the Doosan. The fuel tank is also quite small at just 100 liters. Travel force is not very strong. Reportedly prone to some minor issues, but it’s relatively affordable for a joint-venture machine. In summary: solid overall performance, suitable for earthwork and rental use.

Final Thoughts

Each model has its pros and cons. Some stand out for durability, some for fuel economy, some for speed, and some for price-performance ratio. When choosing a 6-ton excavator, consider your main job type, fuel cost, and expected reliability to pick the one that best suits your needs.

Selecting the right hydraulic breaker (also known as a rock hammer) is a critical technical decision that directly impacts work efficiency, equipment lifespan, and overall cost-effectiveness. The key is to ensure that the breaker matches your excavator and actual working conditions for optimal performance.

1. Proper Match with the Carrier (Top Priority!)

1) Carrier Operating Weight
This is the primary basis for selecting a breaker model. Manufacturers typically specify a recommended carrier weight range (e.g., suitable for 15–25 ton excavators). It is essential to ensure that your excavator’s actual operating weight falls strictly within this range. Using an undersized or oversized breaker can damage the carrier or result in poor performance.

2) Carrier Hydraulic System Parameters

• Operating Flow (L/min)
  This is the most critical hydraulic parameter. The breaker requires a specific oil flow range to deliver optimal impact performance.

  • Insufficient flow: Weak impact force, low frequency, and poor efficiency.
  • Excessive flow: Overheating, seal damage, and possible internal failure of components (such as piston or valve).
  • Always verify carefully: The breaker’s recommended flow range must match the flow your excavator’s auxiliary (or attachment) circuit can reliably supply. Refer to your excavator’s operation manual for accurate data.
• Operating Pressure (Bar/MPa)
  The breaker has a rated working pressure requirement. Ensure that your excavator’s auxiliary circuit can provide sufficient maximum working pressure to meet this requirement.

3) Hydraulic Hose Connection Sizes
The breaker’s inlet (high-pressure) and return hose fittings must match the quick couplers or hard pipe fittings on the excavator arm exactly. Mismatched sizes can cause leaks, pressure loss, or inadequate flow.

4) Mounting Dimensions
The breaker bracket’s ear width and pin hole diameters must fit the excavator arm’s mounting dimensions precisely. Improper fitment can cause installation issues, instability, or serious safety risks (such as pin breakage or hammer detachment).

2. Match to Working Conditions (Efficiency Depends on It)

1) Material Hardness

• Soft/Medium-hard materials (e.g., soil layers, asphalt, limestone): Opt for breakers with higher blow frequency for better productivity.
• Medium/Hard materials (e.g., reinforced concrete, sandstone, granite): Impact energy becomes more important. Select models with higher impact energy for effective breaking.
• Very hard materials (e.g., basalt, quartzite): Choose a heavy-duty breaker with maximum impact energy and consider using specialized chisels (e.g., cone-type chisels).

2) Type of Work

• Demolition (concrete structures with rebar): Requires moderate impact energy and good frequency. Be mindful of rebar wrapping around the chisel.
• Mining/Rock Breaking: High impact energy is essential, along with excellent wear resistance and reliability.
• Frozen Soil Breaking: Needs good impact durability and relatively high frequency.
• Trenching/Slope Trimming: May require a more compact and slender breaker design, and sometimes a flat chisel for better precision.

3. Understanding Breaker Performance Parameters

1) Impact Energy (Unit: Joules)
Indicates the energy delivered per blow. It is the key metric for breaking hard materials — the higher the value, the better the capacity to break tough materials. Choose sufficient impact energy based on target material hardness.

2) Blow Frequency (Unit: Blows per Minute)
Indicates the number of blows delivered per minute. Higher frequency improves efficiency for breaking soft materials, ensuring smooth surfaces or quick material removal. Typically, higher impact energy models have lower blow frequencies.

3) Chisel Diameter (Unit: mm)
Directly affects the transmission of impact energy and the chisel’s wear resistance.

• Larger diameter: Higher energy transfer and wear resistance but heavier, requiring a larger carrier.
• Smaller diameter: More flexible and lightweight, suitable for smaller carriers and softer materials, but lower wear resistance and impact capacity.
  Select an appropriate chisel diameter according to carrier weight and material hardness/abrasiveness.

4) Accumulator Nitrogen Pre-Charge Pressure
The breaker’s internal accumulator must be charged to the specified nitrogen pressure. This directly affects impact force and frequency. Always charge and check it according to the manufacturer’s specifications — incorrect pressure can severely reduce performance and lifespan.

4. Quality and Reliability Considerations

• Manufacturing Quality and Materials
  Pay attention to critical components (cylinder body, piston, front/middle/rear housing, accumulator) — high-strength alloy steel and precision machining (heat treatment, surface finishing) are vital for durability and fatigue resistance.
• Sealing System
  The quality and design of hydraulic seals determine long-term reliability and help prevent oil leaks.
• Technical Maturity
  Understand the manufacturer’s technical background and the proven track record of the product series — mature and stable designs typically have lower failure rates.
• User Feedback and Market Validation
  Gather feedback from the industry or peers on the real-world performance, reliability, and common failure issues of specific models.

5. After-Sales Service and Long-Term Operating Costs

• Spare Parts Availability
  Confirm that wear parts (chisels, pistons, seals, accumulator diaphragms, hoses, etc.) are easily available, reasonably priced, and supplied promptly. Spare parts cost is a major factor in long-term operation.
• Local Technical Support
  Check whether the supplier or manufacturer has professional service staff or authorized service centers in your area, and whether they can provide timely installation support, troubleshooting, and maintenance.
• Ease of Maintenance
  Evaluate whether the breaker’s design facilitates routine maintenance and easy replacement of key parts — this directly affects uptime and maintenance costs.
• Technical Documentation
  Ensure that a complete and clear operator manual, maintenance guide, and parts diagrams are provided.

Conclusion:
A well-chosen hydraulic breaker matched properly to your excavator and work conditions will maximize efficiency, extend equipment life, and save you significant costs in the long run. Take time to evaluate both technical parameters and service support before making your purchase.

Life doesn’t give us endless decades — time is short, and wherever you invest your energy, whether or not it bears fruit, it always becomes part of your unique journey. Who can step into the same river twice? So, allow me to share my personal reflections over these years — a way to self-examine, to savor lessons learned, and to keep growing through trial and error.

In construction, machinery, and for us front-line workers, there’s little we can do to change the big picture. But within our own small circles, we can keep learning as we work, watching as we learn, and find calm amid an unpredictable current. If we can breathe steadily and find our own rhythm, maybe we can swim further, with a healthier body and mind.

When I was young, construction machinery was a rare sight, and most projects were small and scarce. Even basic tasks like widening and deepening irrigation ditches were done by sheer manual labor — what we used to call “ba gong” (digging by hand).

Go back even further: the Grand Canal running past my hometown was literally dug out by human hands. Imagine, with today’s know-how, building the Grand Canal would be so easy for modern Chinese people — almost effortless. From the economic boom of the 1980s to the few decades up until the pandemic, progress has been nothing short of astonishing. We all know the old phrase: “Which brand makes the best excavator?” — everyone’s heard it by now.

Just look at the rise of construction: state-owned giants, international deals, massive real estate booms — all blazing ahead like a rocket. But during the pandemic — triggered by an invisible microorganism — that rocket seemed to stall mid-flight. It didn’t exactly fall off a cliff, but if you look at the sales numbers of major machinery brands, you’ll see the trend clearly.

Where I work — here in a third- or fourth-tier city — things have changed dramatically in just a few years. Operator day rates skyrocketed to 400 yuan for an 8-hour shift, paid in cash. Even with fuel savings and fewer working hours, demand still outstripped supply. Sometimes you couldn’t even find a good operator, and mini excavators (which used to be cheap) were suddenly renting for 450 yuan per shift. This is the reality where I live and work.

These days, in my city, the going rate for a mini excavator operator is around 300–350 yuan for a day shift, while a full-day operating fee can easily reach 900 yuan — and you still have to take the job. One year, our local excavator association even organized a meeting to set the hourly rate at about 120–130 yuan, but in hindsight, that seems laughable. It’s like trying to set a house price at 10,000 yuan per square meter, but in practice you can only sell it for 7,000 or 8,000 — prices can crash overnight. Deals happen — or don’t — regardless of personal expectations. For ordinary people like us, all we can do is accept reality and keep moving forward.

Externally, we sometimes face restrictions. Internally, heated competition and lack of trust, along with weaker spending power, make things harder. I hope this downward spiral won’t continue. May every family connected to construction machinery find stability and peace in this “after the whale falls, all things thrive” moment.

I’m not being pessimistic or alarmist. Thankfully, a few buddies and I still run our mini excavators, taking shifts and earning around 10,000 yuan a month — not bad at all. Only January, December, and the rainy season are a bit slow; the rest of the year is manageable.

The most important thing is to do things the right way, to reflect on our actions from different roles and perspectives, and to take responsibility for problems when they arise. It’s not about whether the boss is good or whether you get approval. If you stay true to your conscience and keep a clear mind, whether you’re a boss, a shift operator, or any other worker on site, you’ll find work, earn trust, gain respect, and seize opportunities.

Let’s encourage each other and keep going!