Blocking a Crusher: Techniques, Tools, and Tales from the Field

[MikePhua]

Introduction
Setting up a crusher on uneven terrain is a routine yet critical task in aggregate and mining operations. Proper blocking ensures stability, safety, and operational efficiency. While traditional wooden blocks remain the go-to method, operators have long sought faster, more adaptable solutions. This article explores various blocking techniques, the physics behind load distribution, and real-world innovations that blend practicality with ingenuity.
Fundamentals of Crusher Blocking
Blocking a crusher involves elevating and stabilizing its frame to ensure level operation. This process affects:
• Material flow: A level crusher promotes even feed and consistent output.
• Structural integrity: Uneven loads can stress frames and components.
• Safety: Proper blocking prevents tipping and vibration-related hazards.
Terminology Notes
• Blocking Points: Designated contact areas under the crusher frame used for support.
• Cribbing: Stacked support materials (often wood or steel) used to elevate and stabilize heavy equipment.
• Hydraulic Leveling Legs: Integrated or external hydraulic supports used to adjust elevation.
• Laser Transit: A surveying tool used to measure elevation and ensure level setup.
Traditional Methods: Wood Blocks and Stone Bedding
Wooden blocks remain the most common blocking material due to their availability and compressive strength. Operators often:
• Lay down a bed of ¾" crushed stone to create a stable base
• Use a laser transit to identify the lowest leg
• Level that leg first, then match others to the same elevation
• Stack blocks in a crisscross pattern for added stability
This method, while time-consuming, offers reliability and adaptability to uneven terrain.
Innovative Alternatives and Field Modifications
Operators have experimented with various alternatives to speed up the process:
• Semi-Trailer Jacks: Welded to the frame for quick elevation adjustments
• Receiver Hitch Slides: Square tubing with threaded rods for manual leveling
• Steel I-Beam Cribbing: Cut to length and boxed at ends for strength and shimming
• Hydraulic Jacks: Used temporarily during setup, then replaced with static blocks
These modifications reflect a blend of necessity and creativity, especially in remote or high-volume operations.
Field Anecdote: The Two-Hour Setup
A contractor in Ohio reported leveling an eight-legged crusher in under two hours using a combination of stone bedding, laser transit, and pre-cut wooden blocks. By offsetting the transit from the front and side, they could measure all legs efficiently. With two workers, the setup became routine, reducing downtime and improving throughput.
Historical Context: Evolution of Portable Crushing Plants
In the 1970s and 1980s, portable crushers were often mounted on trailers or sleds, requiring manual blocking at each site. As demand for mobility grew, manufacturers introduced hydraulic leveling legs and modular frames. However, many legacy units remain in service, relying on traditional blocking methods.
In 2010, a safety bulletin from a Canadian mining firm emphasized the importance of proper cribbing after a crusher tipped during setup due to uneven blocking. The incident led to revised protocols and mandatory use of laser leveling tools.
Modern Implications and Safety Considerations
Improper blocking can lead to:
• Frame distortion and misalignment
• Vibration damage to bearings and shafts
• Increased wear on conveyor belts and screens
• Safety hazards during maintenance and operation
Operators are encouraged to:
• Use non-compressible materials for final blocking
• Avoid makeshift supports like cinder blocks or unboxed lumber
• Inspect blocking points for rust, deformation, or weld fatigue
• Document setup procedures for repeatability and training
Recommendations for Efficient Blocking
• Pre-cut blocking materials to standard dimensions
• Use laser transits or digital inclinometers for precision
• Consider semi-permanent jacking systems for frequent relocations
• Train crews on load distribution and cribbing safety
• Maintain a blocking kit with shims, wedges, and leveling tools
Conclusion
Blocking a crusher may seem like a mundane task, but it’s a cornerstone of safe and efficient operation. Whether using time-tested wood blocks or custom-fabricated jacks, the goal remains the same: stability, precision, and reliability. Through shared experience and continuous innovation, operators continue to refine this essential practice—one block at a time.