6.3　Unloading of Bulk Materials

6.3.1　Unloading of bulk materials from rail cars shall comply with the following requirements:

a）If bulk materials are sourced from fixed suppliers in short distance，self-dumping rail cars should be used and underground material receiving troughs should be constructed.The number of standby selfdumping rail cars should not be less than 15%.

b）If daily unloading volume is more than 4000t，one tipper may be provided to unload rail cars，and if daily unloading volume is above 7000t，two tippers may be provided.

c）Rotary tippers（C-type）are preferred，and if ground water table is shallow，side tippers may be selected.

d）The unloading line equipped with tippers should be of turn-back layout，and shunting locomotives shall also be provided.If only one tipper is provided or there are non-typical rail cars that can not be tipped，appropriate unloading equipment shall be provided in addition to the cleaning provisions made for emptied rail cars.

e）If daily unloading volume is within 1000t-4000t，screw unloaders or chain bucket unloaders may be used.

f）Where screw unloaders are used，enclosed or semi-enclosed underground material receiving conduits shall be constructed，and normally，the length of such conduits should not exceed the total length of 10 rail cars.In regions with poor geological conditions and shallow ground water table，deep underground material receiving conduits should not be constructed.

g）If daily unloading volume is below 1000t，chain bucket unloaders or grab cranes may be used.

h）Where loading/unloading bridges or grab cranes are used for unloading operation，the volume of the grabs should not exceed 3m3，and the grabs shall be opened in the rail car length direction.The duty rating of grab cranes shall not be less than Class A6.

i）Where chain bucket unloaders are used together with loading/unloading bridges or gantry grab cranes for unloading operation，the chain bucket unloaders should be arranged at the side of the fixed leg of the loading/unloading bridges or the gantry grab cranes.

j）If the unloading line does not have enough length to allow all rail cars for arriving to the plant at a time，parking tracks and shunting facilities shall be provided.

k）In very cold regions，if bulk materials delivered to the plant by railway are frozen and difficult for unloading，de-freezing facilities may be provided，and gas fired infrared radiation de-freezing warehouses should be constructed.

l）Capacities of main unloading machines are given in Table 5.

Table 5　Capacity of Unloading Machinesunit:t/h

6.3.2　Unloading of bulk materials from ships shall comply with the following requirements:

a）Types of ship unloaders shall be selected based on various factors such as unloading volume，material properties and wharf types.Main parameters of ship unloaders shall be determined according to the design ship types and water level.

b）Bridge grab ship unloaders with towing tractors should be used，and if conditions permit，continuous ship unloaders or self-dumping ships may be used.

c）The tracks of traveling ship unloaders shall have enough length to ensure unloading from the fore cabin to tail cabin，and stops shall be provided at two ends of the tracks.