Background
A limestone quarry in Turkey was operating a three-stage conveyor system to move crushed limestone from the quarry floor to the primary stockpile at the plant entrance β a vertical lift of approximately 28 meters over a horizontal distance of 60 meters. The system used three separate flat belt conveyors with two transfer points, each with a transfer chute and corresponding dust emission points.
The operation had two recurring problems:
Dust. Each transfer point was a significant dust source. The quarry was located near a residential area and was receiving complaints about dust. A dust suppression system had been added but required constant maintenance and was only partially effective.
Transfer point maintenance. Two transfer chutes meant two points of regular wear liner replacement, two points of belt scraper maintenance, and two additional drive systems. Each transfer chute required liner replacement every 2β3 months.
The quarry manager was looking for a way to simplify the system and reduce dust.
Analysis
The geometry of the problem β 28 meters of lift over 60 meters of horizontal run β gives an angle of approximately 25Β°. This is within the capability of a chevron belt (which handles up to 35Β°) but would require a relatively steep configuration for a flat belt.
However, the quarry preferred to eliminate the intermediate transfer points entirely rather than simply reconfigure the incline angle. A sidewall conveyor belt was evaluated as a single-conveyor replacement for the three-stage system.
A sidewall belt configuration was designed: - 650mm base belt width - 200mm corrugated sidewall height - Cross-cleat spacing: 400mm (compatible with limestone top size of 80mm after secondary crushing) - Conveying angle: 35Β° - Belt length: approximately 90 meters (following the terrain rather than the straight-line distance) - Capacity: 300 tonnes per hour at 1.2 m/s
Installation
The three existing conveyors and two transfer chutes were decommissioned. A single sidewall conveyor was installed on new steel structure following the quarry access ramp terrain. The drive was positioned at the top (head end). A single loading chute was built at the quarry floor level.
Installation took approximately 3 weeks including structural work. The belt was pre-jointed in the workshop and installed as a complete loop.
Outcome
Dust: With a single loading point and enclosed material transport (sidewall belt encloses material between the sidewalls and cross cleats), dust at the intermediate transfer points was eliminated. Dust levels at the plant entrance stockpile were within acceptable limits without additional suppression.
Maintenance: Two transfer chutes, four belt scrapers, and two intermediate drive systems were eliminated. The single sidewall conveyor required: - Sidewall inspection quarterly (checking for cracking or delamination) - Cross-cleat inspection every 6 months - Drive system maintenance on standard schedule
Overall maintenance time for the conveying function reduced by approximately 65% compared to the three-stage system.
Carryback: The sidewall belt does produce carryback β material adheres to the cross cleats and releases on the return run. A return belt cleaner was installed at the head end to catch carryback before it reached the tail end. This is a known limitation of sidewall belts that was planned for in the design.
Key Points
Sidewall belts eliminate transfer points. In applications where dust and transfer point maintenance are the primary problems, consolidating multiple conveyors into a single sidewall conveyor often solves both simultaneously.
Carryback must be planned for. Sidewall belts cannot be cleaned as effectively as flat belts. Return cleaner placement at the head end is essential.
Sidewall belts are not for all materials. In this application, secondary crushed limestone at 80mm top size suited the 400mm cross-cleat spacing well. For different materials or particle sizes, the cleat geometry needs to match.
Elephant Rubber supplied the sidewall conveyor belt for this project.