Building a Forest Access Road with a Komatsu PC200-3

[MikePhua]

The Komatsu PC200-3 and Its Role in Land Development
The Komatsu PC200-3 hydraulic excavator, introduced in the late 1980s, was part of Komatsu’s third-generation lineup aimed at improving reliability, hydraulic efficiency, and operator comfort. Komatsu, founded in 1921 in Japan, had by then become a global leader in construction equipment, rivaling Caterpillar in many markets. The PC200-3 featured a robust undercarriage, a 6-cylinder Komatsu engine delivering around 125 horsepower, and a hydraulic system capable of precise control in forestry, excavation, and road-building applications.
Though production of the PC200-3 ceased decades ago, thousands remain in service worldwide, especially in rural and owner-operated settings. Its mechanical simplicity and durable frame make it ideal for tasks like clearing land, grubbing stumps, and shaping terrain for access roads.
Clearing and Grubbing in Mixed Forest Terrain
Constructing a half-kilometer access road through dense forest requires more than brute force—it demands a methodical approach to clearing, grubbing, and base preparation. In this case, the operator began by harvesting large maple and birch trees for firewood, then transitioned to stump removal using the PC200-3’s thumb-equipped boom.
Grubbing refers to the removal of stumps, roots, and organic debris from the soil. This step is critical: leaving organic matter beneath a road base can lead to settling, instability, and premature failure. The operator stripped the topsoil and organics down to clay, exposing a layer of shale roughly 4–6 feet below the surface.
Culvert Installation and Drainage Planning
A 20-foot culvert was installed to span a small creek, which had been eroded by ATV traffic. Proper culvert bedding is essential to prevent sagging and washouts. The recommended method involves:

• Excavating below grade to allow for a gravel base
  
• Compacting ¾-inch crushed rock under and around the pipe
  
• Using riprap (large angular stone) at the inlet and outlet to prevent scour
  
• Holding the culvert in place with the excavator while backfilling
  

This approach ensures that the culvert remains stable under load and resists erosion during heavy rains. In regions like Nova Scotia, where freeze-thaw cycles and seasonal runoff are common, culvert integrity is vital to long-term road performance.
Shale as a Road Base Material
The site had access to clean shale ranging from sandy fines to larger, easily fractured rocks. Shale can be an effective road base if properly compacted and mixed. However, its performance depends on moisture content and clay ratio. Dry shale behaves like cement, but excessive clay can make it slick and unstable when wet.
To optimize shale use:

• Mix clay and shale during excavation to create a uniform fill
  
• Use the excavator to break up larger chunks and walk them in
  
• Run a loaded dump truck over the fill to identify soft spots
  
• Rework any depressions with fresh shale and compact again
  

In one example from Pennsylvania, a contractor used a similar shale-clay mix to build a logging road. By alternating passes with a dozer and loaded trucks, they achieved a firm surface that held up for over a decade with minimal maintenance.
Equipment Synergy and Operator Ingenuity
The road-building effort relied on a 1988 Komatsu PC200-3, a 1970s White Constructor dump truck, and a farm tractor for fill distribution. While lacking a dozer, the operator used the excavator’s thumb and boom to manipulate material and compact the base. This kind of improvisation is common in rural builds, where budget constraints and equipment availability shape the workflow.
The thumb attachment proved invaluable for handling brush, logs, and rocks. It allowed the operator to sort debris, place riprap, and manipulate culvert sections with precision. In forestry applications, thumbs dramatically increase productivity and reduce the need for manual labor.
Topsoil Removal and Subgrade Preparation
Stripping topsoil is a non-negotiable step in road construction. Topsoil contains organic matter that decomposes over time, leading to voids and instability. Beneath the topsoil, the clay layer was exposed and used as a subgrade. While clay can be problematic when wet, it provides a stable base when dry and properly compacted.
Recommendations for subgrade preparation:

• Remove all organic material, including roots and humus
  
• Grade the clay layer to promote drainage
  
• Avoid building on wet clay—wait for dry conditions or stabilize with lime
  
• Use geotextile fabric if mixing materials or bridging soft spots
  

In areas with high water tables, additional ditching may be required to prevent saturation. In this build, only a short section needed ditching to direct runoff toward the culvert.
Lessons from the Field and Practical Advice
This road-building effort highlights several key lessons:

• Use what you have, but understand its limits
  
• Plan drainage early—water is the enemy of road longevity
  
• Mix and compact materials thoroughly to avoid future repairs
  
• Monitor the road during and after construction to identify weak spots
  

One operator from Saskatchewan noted that shale roads can be hard on tires, especially when large fragments are left unbroken. Regular passes with the excavator or tractor can help crush and settle the surface.
Conclusion
Building a forest access road with legacy equipment like the Komatsu PC200-3 is a testament to resourcefulness and mechanical know-how. With careful planning, proper material handling, and attention to drainage, even a modest fleet can produce a durable road capable of supporting farm tractors and light vehicles. As landowners continue to develop remote properties, the principles demonstrated here—clear grubbing, culvert bedding, shale compaction, and adaptive equipment use—remain timeless.