Cable (Electric) Shovel in Coal
Cable (Electric) Shovel in a Metal Mine
Note “raking” motion of dipper.
What does it do to selectivity?
More On “Raking”
Hydraulic Shovel
Are these different machines?
Note:
1. Positioning of both
2. Boom length
Note bucket motions: three directions!
Shovel / Backhoe Digging Range
Hauler & face to be within the digging envelope!
Loading Equipment Selection
Basic Considerations
1. Bucket / dipper size
2. Vertical and horizontal clearance
3. Cycle time
4. Ability to cope with site specific conditions
Loader Geometry
How Big A Loader ?
1 Bucket size
a. bench height
b. selectivity of mining
c. loading rate
d. size of transport equipment
2. Bucket reach
a. vertical reach: clear the edge of the truck box
b. horizontal reach: reach at least to the truck box center
Note 1: For a given loader there is a trade-off between the bucket size and its reach (determined by tipping torque).
Note 2: Extended reach equipment is available; it trades bucket size for extended reach
Target Area ?
How Many Loader Buckets ?
1. Target area to allow unrestricted loading
a. Relative size of loader bucket and truck tray
2. Impact load not to damage the truck
3. Minimize truck loading time
a. Truck needs to move to earn money
4. Allow the required selectivity of mining
General guideline: 3 to 5 buckets
Terex
Selecting a Loading Tool
1. Determine the required production
2. Determine the number of working faces / benches
3. Determine loader cycle time and cycles per hour
(note: you need to assume the machine size to define cycle time)
4. Determine the required bucket payload
5. Determine the required bucket size and type
6. Select the machine using bucket size and payload as criteria (to meet the production requirement)
7. Check the tipping load, if loader
8. Compare the cycle time to that assumed; rework if a difference exists