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Show Coal Handling 3.1 Delivery Delivery to power stations and other large users is mostly by rail, using permanently coupled trains. Rapid loading and discharge systems have been developed with trains forming a 'merrygoround'. About 5% of coal output is transported from mines in the north east to power stations in the south east by sea. Coal for domestic and most industrial use is taken to private distribution companies, either directly by road or rail or via strategically located storing depots. The distribution companies then transport coal to the user by road. Three types of delivery vehicle are available: tipper lorry, conveyor lorry and pneumatic delivery lorry. Because of their versatility and relatively low operating and maintenance cost, tipping lorries are the most economical. Conveyor lorries incorporate a hydraulically driven belt conveyor located at the back of the vehicle which can swing through 180 and deliver coal to a height of 2.8 m thus providing greater flexibility than the tipper. Pneumatic delivery lorries use a positive displacement blower to provide conveying air enabling the coal to be transported, via 125 mm diameter flexible pipe, to storage hoppers up to 40 m from the vehicle. This method is particularly suitable to the smaller consumer because it can deliver coal to a service hopper from where it can flow by gravity to the boiler. A novel method of delivery currently being evaluated is supplying coal in closed containers! Specialised unloading and coal extraction systems are required at the customer's premises but the cost of this should be offset by improved vehicle utilisation. Reduction of site contamination makes this an environmentally acceptable method. 3.2 Reception and storage The conventional method for receiving coal at a site is for it to be discharged from the rail track or tipper lorry into a reception bunker below ground. From this bunker the coal is conveyed, mechanically or pneumatically, either to the point of use or to medium or long term 20-21 |