Overland Conveying Taking the Straight Line across Sand, River and Farmland
There is a number of obstacles which can make the transport of raw materials considerably more complicated and expensive. In many cases local factors such as mountainous terrain, heavily populated areas or wide rivers interfere with a smooth material flow. There is an alternative system of transport with which almost all obstacles can be overcome.
Long detours may make the transport of raw materials from the mining area to the processing plant considerably more complicated and expensive. In many cases, however, local factors such as mountainous terrain, heavily populated areas or wide rivers interfere with a smooth material flow. This report describes the situation of a cement plant in Sudan, where a direct, straight link between the mining area and the processing plant seemed impossible to establish. The report then goes on to present Ropecon as an alternative system of transport with which all difficulties could be resolved.
To meet the daily demand of 9000 t of limestone for Berber Cement Company's new cement plant, a modern crushing plant has been installed 8 km away from the processing plant on the western side of the River Nile. Land transportation of 9000 t per day encounters a massive natural obstacle: the Nile, the world's longest river and approximately 850 m wide in this area. The transport of the material from west to east can only be done by constructing a bridge across the river, by using small barges or by using a ropeway-type system, crossing the river between two towers.
At the time of the plant study, there was no existing bridge in the area nor were there any plans for constructing a new bridge. To overcome these difficulties and to find the most economic and reliable solution, a study was commissioned to investigate whether Ropecon might be a suitable alternative. The system is briefly described below, and the report then details the solution worked out for Berber Cement.
The Ropecon System Components
Ropecon is designed and manufactured by the Austrian company Doppelmayr Transport Technology. The system combines proven ropeway technology with the features of conventional belt conveyors. The continuous conveyor is elevated off the ground, thus reducing space requirements on the ground to a minimum. Ropecon easily crosses obstacles such as deep valleys, mountainous terrain, rivers, roads or other infrastructure, thus allowing for a straight route between the loading and the discharge point while avoiding unnecessary detours. The below description briefly explains the main components and features of Ropecon and highlights the potential of the system as well as possible applications.
Belt and Wheel Sets
Ropecon consists of a flat belt with corrugated side walls. The belt may be fabric-reinforced or a steel cord belt, depending on the application. The corrugated side walls are cold-bonded or vulcanized onto the belt. The individual belt sections are joined by way of vulcanization to form one continuous belt, just as on conventional belt conveyors.
The belt is fixed to steel axles arranged at regular intervals which support the belt. Polyamide running wheels are fitted to either end of the axles. These wheel sets run on track ropes and provide positive belt guidance while preventing the belt from skewing. The combination of polyamide wheels on steel track ropes minimises rolling resistance and therefore energy requirements.
Support Structure Components
The galvanised, fully locked steel track ropes on which the wheel sets run are of the type used for suspension bridges or ropeways. Ropecon uses 3 pairs of ropes: The bottom-most rope pair supports the bottom belt while the rope pair in the middle supports the top belt. The upper-most rope pair gives additional stability to the structure and serves as the travelling rope for the inspection vehicle by means of which each point along the line can be accessed. Track rope frames are fitted to the ropes at regular intervals to maintain the ropes in their relevant position and to distribute the loads. The ropes have fixed anchoring at both ends and are guided over tower structures, similar to passenger ropeways. Depending on the terrain and on the individual requirements of each project, different types of Ropecon tower structures are used.