2. Types of Mine Cars, their design & Possible choice factors.
Granby Ore or Mine Cars are a robust proven design. The cars are amongst the most robust resulting in long
service life. They tip to the side with a dolly wheel engaging a ramp. They are not suitable for sticky ore as it
can build up in the ore box. Granby cars can be supplied in sizes anywhere between 2m3 and 8m3. The
traditional type Granby mine cars are widely used in underground mining operations where extraction requires
high volumes at low cost. They have a side wheel which helps in side dumping. At dumping site a special type
of slope is made as shown in the figure just on the contrary of the dumping side. When the car reaches the site,
the wheel runs on the slope, tilting the car in result & that tilting is the dumping phenomena in this case.
1. Greater Capacity (40-180 ft3
2. Per unit cost is less.
3. High speeds.
4. Feasible for smaller gauge curvatures.
5. Suitable for non-sticky ore.
6. One side dumping.
3. 7. Automatic dumping.
8. Can handle heavier ores as well.
9. Wider gauge width (27”-36”).
10. No uncoupling required while unloading.
Among the smaller capacity cars, the most popular and most widely used are the gravity dump types, such as
rocker dump, designed so that the weight of the load tips the body when a locking latch is released by hand.
The body of this type is balanced to right itself after the load is discharged. Rocker dump cars range in capacity
from 1 yd3 (0.76 m3) hand loaded types, to units of 10 yd3 (7.6 m3) for power shovel loading. It is a V shaped
car which is rounded at the bottom & can dump on either side. After dumping it can come back to its upright
1. No material leakage along haulage ways.
2. Track gauge is small (18”-24”).
3. All types of material can be transported (sticky, dry, etc).
4. Both Side dumping.
5. Useful for low Capacity of 20-40 ft3
6. Less maintenance cost.
7. Tight body therefore long lasting.
9. Feasible for more gauge curvatures.
4. End Dump Car
There are different types of End dump cars such as scoop cars, S shaped, Z shaped. The dumping takes place at
the back side instead of the side. There is a door on the back side, which opens when the bucket of the car is
lifted backward, therefore unloading takes place in such a way. This bucket is attached with the bottom by a
rear; there is a hook on the front side which is attached with the bottom when loaded, while unloading this
hook is detached. This type of car is usually used for hand tramming in small mines.
1. Low capacity (11-28 ft3
2. Narrow gauge (18”-24”).
3. Manual dumping usually.
4. Small mine over heads.
5. Good for non-sticky material.
7. Low maintenance cost.
5. Gable-Bottom Car
It is W shaped in cross-section and unloading takes place at both ends via doors. They can be built for large
capacities even with narrower gauges. Different gauges as well as various capacity gable bottom cars are
available. There are several door mechanisms and doors are made of very strong material because of the fact
that they are used severely, so they are braced strongly. These door mechanisms include hinges, spring draft
gears & internal or external bracing by means of which the door is opened or closed.
1. Variable capacity cars (18-180 ft3
2. Variable gauge (18-36 ft3
3. Variable heights complimenting the height of the drifts & mine.
4. Suitable for non-sticky ore.
5. Greater lifetime.
6. Two way dumping.
7. Even unloading.
8. Greater capacity to gauge ratio.
Solid or Box type Cars.
This type of car is the strongest with no doors, it usually is short in height & less in width too but it is long,
thus making it less suitable for tracks with more curvature. Their unloading phenomenon is rotary dumping.
Cars can be dumped either as a single uncoupled unit or by using swivel couplings.
1. High capacity.
2. Narrow gauge.
3. Greater lifetime.
4. Low maintenance cost.
5. All types of material can be used.
6. Low in height.
Other quantitative figures are similar to the Granby mine car.