1.2 Km Overland Conveyor
Continued - page 2 -
Detailed design was carried out at Nippon Conveyor’s head office in Osaka, Japan over a four months period. Special attention was paid to idler spacing and inclination to cope with high tension imposed onto idlers at tight curved area. To realize stable operation balancing high tension created by inward belt tension and outward force created by idler configuration under both loading and unloading condition, inverter control with elaborate programming was employed.
Also taken into consideration was decreasing coefficient of friction between belt and idler due to frozen belt surface in winter season. Located in one of the foremost heavy snowfall area in Japan the construction site, conveyor was totally enclosed to prevent snow falling onto conveyor component.
Total installation period was 20 weeks. Conveyor commissioning started March 2005 and handed over to the client in April 2005.
2. Conveyor Design
2.1 Conveyor Arrangement
The 1.2 km-long conveyor was designed to be put along existing road having seven horizontal curves. The smallest radius is 300 meters and the largest 750 meters. To minimize land grading, careful study was carried out for optimum solution.
For the purpose of easing belt tension at carrying side so that small radius curve can be realized, booster drive unit is installed between head and tail section.
The idler spacing for linear portion of carrying side is 1500mm and curved portion is 750 mm. For return side, idler spacing is 3000 mm for the full length of the conveyor both linear and curved portion.
Fig. 2:
300 m radius curve
Attachments
■
1.2 Km Overland Conveyor
Continued - 3 -
2.2 Conveyor component
To cope with belt movement in lateral direction at curved area, employed length of center roller is 265mm in conjunction with 315mm-long wing rollers for both sides.
The conveyor capacity is 700 t/h with 750mm width belt of ST-500. Each 110kW drive units are installed at discharge end and intermediate part of the conveyor.
Belt safety factor is 10.2. Cover thickness is 8.0mm for top cover and 4.0mm for bottom.
Belt trough angle is 45 degrees for carrying side and 10 degrees for return side.
Idler roll diameter is 114.3mm for both carrying and return sides.
Gravity take-ups are located adjacent to the conveyor discharge point. Due to minimizing discharge station height, double take-ups of 2.5m stroke were employed.
3. Operation
It has past more than one year since the start of commercial operation having experienced heavy snowfall in first winter.
Although minor modification to seal joint gap to prevent snow gets inside had to be done, no major malfunction has occurred so far.
Fore more information on Nippon Conveyor Co., Ltd. please visit:
https://edir.bulk-online.com/profile...n-conveyor.htm
Fig. 3:
Curve conveyor passover
Attachments
■
1.2 km Overland Conveyor with Tight Horizontal Curves
1.2 km Overland Conveyor with Tight horizontal curves of 300 meter radius
Nippon Conveyor Co., Ltd.
Japan
1. Abstract
Nittetsu Mining Co., Ltd. (Nittetsu) is a leading Japanese limestone mining company having several mines all over Japan.
The company also owns copper mine in Chile.
Shiriya Mine, which is located northernmost part of Japan among several limestone mines owned by the company, produces 4.5 million ton per annum of limestone and ships to customers throughout Japan.
Production commenced in 1958. Narrow gauge rolling stocks pulled by diesel locomotive hauled the product.
Long-lasting transportation with narrow gauge railway was replaced with conveyor system in 1994 as part of streamlining.
Several years later, as production progresses, new conveyor line was planned to connect between new limestone stockyard and nearby cement factory in 2003.
Existing several horizontal curves and cement factory facilities on the path of conveyor travel, originally planned conveyor system consisted of seven straight line conveyors for connecting 1.2km distance to avoid obstacles.
The innovative design of connecting the stockyard and the factory with single- flight-horizontally-curved conveyor was offered by Nippon Conveyor for more economical solution and ease of maintenance.
Nippon Conveyor is Japan based conveyor specialist since its establishment in 1949. At an early stage in 1950s the company achieved several-hundred-meter long single flight conveyor despite then perception that even a-hundred-meter long conveyor was considered to be long distance one. Thereafter the company has been supplying high-volume basic materials industries worldwide with conveyor systems.
After the in-depth study carried out by Nippon Conveyor, Nittetsu Mining Co., Ltd. approved configuration of conveyor line with seven horizontal curves ranging from 300 to 750-meter radius in 2004.
Fig. 1:
General arrangement drawing
Attachments
nippon_1 (JPG)
■