Middle Trough for Underground Scraper Conveyors in Coal Mines
The middle trough is one of the core structural components of the scraper conveyor system used in underground coal mines. It forms the primary load-bearing section of the conveyor line and acts as the channel in which the scraper chain and material move. Designed to withstand harsh underground conditions, including high load, humidity, corrosion, and abrasive wear, the middle trough plays a decisive role in the conveyor's reliability, service life, and overall productivity.
The middle trough is typically fabricated from high-strength wear-resistant steel plates, such as NM400, HARDOX 450, or Q345B with additional hardfacing. It features a U-shaped or channel-type profile with thick sidewalls and a reinforced base. The inner surfaces are often treated with anti-abrasion coatings or replaceable liners to prolong lifespan. The structural rigidity is enhanced with welded ribs or press-formed profiles to minimize deformation under dynamic load.
Key design aspects include:
Chain path guidance rails
Recessed scraper guide tracks
Bolt or pin-type connecting flanges
Dust-sealed side channels
Drainage and debris ejection ports (optional)
Standard dimensions vary depending on the scraper conveyor model (e.g., SGB620/40T, SGB764/132, SGB1000/160), but typical lengths range from 500mm to 1750 mm per segment.
In operation, the middle trough supports the scraper chain, coal material, and the reciprocating motion of the scrapers. It must resist not only the vertical load of bulk coal but also the lateral forces generated by chain oscillation and directional shifts. Proper material selection and precise fabrication ensure low friction, low resistance transport, and minimal material carry-back.
Performance advantages:
High mechanical strength and load-bearing capacity
Superior wear resistance against abrasive coal particles
Compatibility with centralized lubrication systems
Modular structure for easy replacement and maintenance
Advanced models may incorporate intelligent wear monitoring plates, curved alignment sections, and adjustable guiding profiles to accommodate different operating layouts.
Depending on the application intensity, the middle trough can be produced in several material combinations:
Mild steel (Q345B or equivalent): Suitable for standard duty, low-abrasion environments
High-strength alloy steel (NM400, HARDOX 450): Excellent wear resistance for longwall operations
Bi-metallic composite panels: Replaceable inner liners made of ceramic or hardened alloy inserts
Surface treatments may include:
Hardfacing welding (e.g., chromium carbide overlays)
Hot-dip galvanization (for corrosion resistance)
Anti-corrosive paint coatings for humid mine environments
The production of middle troughs involves high-precision cutting (plasma or laser), CNC bending, robotic welding, and dimensional inspection. All welding joints are stress-relieved and quality-checked using ultrasonic or magnetic particle inspection (MPI). The assembly line ensures consistent quality, tight dimensional tolerances, and high throughput for bulk orders.
Each trough undergoes:
Raw material quality certification
Assembly fitting test
Final dimensional inspection
Surface treatment and packaging
Custom fabrication is available based on customer drawings, technical specifications, and interface requirements with head/tail sections and sprocket modules.
Middle troughs are connected by bolts, hinge pins, or quick-lock couplings, ensuring fast assembly underground. To reduce downtime, modular interchangeability allows defective sections to be replaced without dismantling the full conveyor.
Maintenance guidelines:
Regular inspection of wear surfaces, especially scraper contact zones
Lubrication of scraper chain to reduce friction and surface wear
Periodic cleaning of debris and coal fines from trough base
Tightening of joint bolts and inspection of alignment
Operators are advised to maintain a spare stock of 5–10% of total trough length for emergency replacement during scheduled or unscheduled maintenance periods.
Middle troughs are used extensively in coal mine infrastructure for material handling, particularly in the following systems:
Longwall face scraper conveyors
Gate road beam stageloaders
Transfer points between crushers and belt conveyors
Backfill and waste rock conveyors in narrow headings
We offer complete design customization including:
Trough length, width, wall thickness
Material selection and surface treatment
Connection flange types and hole patterns
Integration with wear sensors, monitoring units, and deflector plates
Our engineering team supports drawing reviews, on-site measurements, sample production, and flexible delivery schedules. We provide full documentation including material test reports (MTRs), welding certifications, and dimensional control reports.
Over 15 years of experience in scraper conveyor manufacturing
ISO and MSHA-certified materials and processes
Proven performance in over 500+ underground installations
Export-ready packaging and multilingual technical support
The middle trough is far more than just a steel channel—it is a mission-critical component in the coal mine transportation chain. A well-designed and properly manufactured trough ensures safe, efficient, and low-maintenance operations, directly impacting production continuity and worker safety. With our extensive manufacturing experience, technical support, and quality assurance system, we are your reliable partner for long-term scraper conveyor system solutions.
For further inquiries, drawings, or quotations, please contact our sales and engineering department.
