Reference no: EM13380198

1. Draw a plan of a typical strip mine showing all operational features and equipment.

2. Answer the following:

a. Why is the working slope of an open pit usually much flatter than the final slope?

b. Provide a sketch to show the difference between the final and the working slopes.

c. Why do operators try to steepen the final slope to an allowable safe maximum angle?

3. Define the following

1. swell factor :-

a. Swell factor

b. Struck Capacity c. HeapedCapacity d. Fill Factor

e. Rolling resistance

f. Bank cubic metre

g. Loose Cubic metre

4. Compare the performance of a hydraulic excavator and an electric shovel.

5. Discuss the factors that favour the use of scrapers over the use of trucks and loaders.

6. Discuss the following:

a. List all the major mining operations that are associated with surface mining.

b. List all the auxiliary operations that are associated with surface mining.

c. Define production scheduling

d. How does production scheduling affect the process of mine planning and design?

e. Name and discuss the overall constraints for production scheduling

7. Answer the following

 a. Define materials handling in surface mining

 b. Name the different types of operations in materials handling

 c. Name the different types of machine used in these operations

 d. Name and discuss the major factors that determine the selection of excavation equipment.

 e. Define the idealised output of a power shovel

8. For the following data for a shovel-truck operation calculate the idealised output in m³/hr.

i. Required production per bench = 5,000 tonnes/shift

ii. Operating period = 2 shift/day (10 hours per shift)

iii. Material = well blasted rock

iv. Working time = 55 mins/hr or 7.5 hrs/shift v. Operating factor = 80%

vi. Specific weight of rock = 2.0 tonne/m³

Calculate the actual shovel production in tonnes/hr given the following: i. Material weight (bank) = 2 tonnes/m³

ii. Swell factor = 30%

iii. Bucket size = 11.5m3 iv. Fill factor = 0.85

v. Cycle time = 30sec vi. Availability = 83 %

9. Answer the following:

a. Discuss the factors that are considered in the selection of a truck as a haulage unit.

b. In determining the cycle time of a haulage unit name the factors in relation to the haulage road that need to be considered

c. Define the following

i. Grade resistance

ii. Rollin resistance

iii. Total resistance

d. Define traction

10. A 90 tonne rear dump truck travels on an 8% grade loose gravel road. Determine the traction and total resistance

i. On the way up when the truck is loaded

ii. On the way up if the truck is empty

For the following conditions:

?Rolling resistance factor = 100 kg/tonne

??Coefficient of friction = 0.35

?Vehicle weight empty = 700 kg/tonne of rated capacity

?Gross vehicle weight = dead weight + capacity

?Grade resistance factor = 10 kg/tonne

?Load distribution = 33 % on front tyres and 67% on rear tyres.

Download:- SURFACE MINING.rar