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This paper answers the following questions –
Question 1
Since ore grades continue to get lower and lower it would seem that we will never run out of metals in the foreseeable future. Briefly analyse and comment on this statement.
Question 2
Dilution in mining is costly but having nil dilution may be even costlier than having dilution. Briefly analyse and comment on this statement.
Question 3
Discuss the points you would consider when selecting a production method or methods for a particular ore body. Indicate which points you consider to be the most important.
Question 4
An ore body is mined by sub level open stoping from a vertical shaft. Draw one or more simple sections to show the following details:
• Ore/waste pass systems
• Stope development
• Extraction level or levels
• Sub-levels
• Slot raises
Question 5
Use sketches to illustrate the rubber tyred block caving stoping system. Where applicable use real examples to illustrate particular elements of the systems.
Question 6
In sub-level caving what are the important criteria in planning the layout of development and supervising extraction?
Question 7
What are the implications in the mining and treatment of sulphide ore, which tends to oxidise readily? What methods could be used to mine such ores?
Question 8
Illustrate a modern longwall coalface including the face and a short section of the gates. Note show all equipment and label the diagram clearly.
Question 9
Compare and contrast room and pillar mining with longwall mining in terms of economics, safety, productivity and depth of cover.
Question 10
Describe a method of shrinkage stoping in detail. What are the advantages and disadvantages of shrinkage stoping over other methods of mining similar orebodies?
Question 11
To be successful in Sub-level caving, careful controlled drawpoint mucking must be practised. Discuss this from a point of view of:
a) An individual drawpoint
b) A group of closely spaced drawpoints
Question 12
Compare and contrast longwall advancing and retreating methods of coal mining.
Question 13
Explain with the aid of sketches the interaction between the powered supports, the AFC and the power loader on a longwall coal face.
Question 14
Describe in detail one method of pillar extraction in room and pillar mining.
Question 15
What methods of room and pillar mining can be applied to the mining of inclined ore bodies? Describe one such method in detail citing an example of its application.
Question 16
Backfill is becoming more widely applicable in underground mining. What methods of backfilling can be applied? Describe these in detail citing examples of their use, advantages and disadvantages of the method.
Question 17
With the aid of sketches describe the mining sequence applied in a mechanised cut and fill mining operation.
Question 18
In relation to underground metalliferous mining define:
a) Recovery
b) Dilution
What methods of sampling are available to determine each of the above?
Question 19
Detail the development and production sequence for a vertical crater retreat (VCR) stope. In what situations can VCR be applied?
Question 20
Describe the components involved in a traditional drill and blast mining cycle and those involved in a continuous mechanised mining cycle. What advantages and disadvantages do both systems of mining have?
Question 21
The diagram below illustrates the amount of coal that is left intact after mining in pillars and the amount of coal that is extracted in the rooms. If a1 = 20m, a2 = 22.5 m, b1 = 5m and b2 = 4.5m determine the recovery ratio in a 2.5 m coal seam.
Question 22
What do the terms transverse and longitudinal mean with respect to the direction of mining within an orebody?
Question 23
Show with the aid of diagrams the development, production and filling phases for a typical open stoping mining setup. What advantages does filling of the stope give?
Question 24
In designing underground accesses to allow entry to ore extraction areas what factors need to be taken into account?
Question 25
Define the following terms, diagrams may help:
a) Chain Pillar
b) Barrier Pillar
c) Crown Pillar
d) Sill Pillar
What other types of pillars are commonly used in mining?
Describe a method of pillar design suitable for the design of a room and pillar mining system. What are the main factors that influence the design of such pillars?
Question 26
Describe with the aid of sketches the layout of a typical South African longwall gold mining system. What particular advantages does this mining method have for mining at ultra-depths?
Question 27
Describe a highwall mining technique in detail, if possible giving details of productivity levels that can be achieved.
Question 28
Describe techniques that can be used to mine very thick coal seams citing examples of their use. Diagrams may be useful.
Question 29
Traditionally coal and metalliferous mining have been regarded as totally separate forms of mining. In recent years the distinction has blurred and some argue that in the modern mining world the differences between the two forms of mining no longer exist. Discuss this statement.
Question 30
In a typical block caving operation the following levels exist:
a) Undercut level
b) Draw or production level
c) Ventilation level
d) Transportation level
Describe the operations and requirements for each of these levels, citing examples wherever possible. What factors influence the spacing between these levels?
Question 31
Airblasting is not uncommon in block cave mines. Describe how a typical airblast can develop. How can airblasts be minimised and what engineering controls can be applied to ensure this?
Question 32
To ensure continuous production from a room and pillar type operation determine the minimum number of headings required to be operating if the production is to be undertaken using:
a) Traditional drill and blast production methods
b) Continuous miners
What methods of ore transportation are applicable with the above?
Question 33
Define the terms overbreak and underbreak. What methods can be used to determine these in a typical production stope and what steps can be used to minimise both?
Question 34
What factors need to be taken into account when designing a typical longwall coal extraction system? How do these factors influence the selection of the coal face equipment?