undreeground metal mining

2. The focus areas of Lecture-4 are:
1. Mine development:
a. Important definitions & introduction to various types of
excavations
b. Mine access
c. Elements of captive and track mine mine
d. Elements of Trackless mine

3. DECIDING FACTORS FOR DEVELOPMENT OF
MINE
All detailed parameter of the deposit are to be
examined.
Shape & depth of the deposit.
Type of the deposit.
Highest Flood Level.
Surface topography and terrain.
Natural and geological conditions
Availability of capital
Operating cost
Demand of mineral
Scale of mining and mining method.
Choice of machinery.
Law of the country.
Environmental and safety factors

4. STRUCTURES TO BE DEVELOPED
MINE ENTRY : ADIT, SHAFT,DECLINE,
INCLINE
DRIFT
RAMP
DRIVE
RAISE: End Raise , Stope raise
ORE PASS
CROSS CUT

5. •ADIT
•SHAFT INCLINE
•SHAFT VERTICAL
•DECLINE
Mine Entry

6. FACTORS FOR DESIGNING OF MINE
ENTRY
Rock mechanics/ stability issues .
Operational procedure/Method
Degree of mechanization
Supporting pattern.
Excavation rate.
Gradient and curvature of the decline.
Economics.
OH&S Management
Environment Protection

7. DECIDING PARAMETERS FOR
MINE ENTRY
• Location:
• HFL
• Surface Topography
• Geological factors.
• Near by water bodies.
• Water seepage rate.
• Dimension:
• Mining Machinery
• Ore hauling system
• Rock mechanical properties.
• Layout of air and waterline.
• Layout of electrical cable
• Drainage system.
• Operational :
• Material handling
• Method of mining
• ventilation

8. STABILITY OF MINE ENTRY
Stability of the mine entry is influenced by:
 LOCATION AND GEOLOGICAL ASPECTS
 DYNAMIC STRESS DISTRIBUTION.
 HYDROLOGICAL CONDITION
 SIZE OF PILLAR(SHAFT PILLAR, ROCK PARTING)
 SUPPORTING SYSTEM
 BLASTING PRACTICE
 PARTING WITH OTHER EXCAVATION
 MACHINE AND EQUIPMENTS
 TECHNICAL EXPERTISE

9. DECLINE
Generally at 6 to 11 degree
Spiral or near spiral suitable
for trackless.
Rectangular in cross section
with arch or flat back.
Generally suitable for ore body near surface
Suitable for any ore body, flat, incline, steeply
dipping.
Has to start from surface by box cut / open cut

10. OPERATIONAL CHALLENGES
Low vertical extension rate.
 Increased Ventilation requirement due to use of diesel equipment.
Ground control and Supporting system.
Communication and emergency response.
Maintenance of decline
Drainage system and pumping arrangement.
Waste rock excavation is high and large dumping area requirement

11. DECLINE ADVANTAGES
Decline allows early starting of the mine
production. Shorter gestation period
Easy man & material handling
Decline allows free movement of
machines, better utilization.
High productivity from mines.

12. DECLINE DISADVANTAGES
Hoisting through decline is costly from greater
depth.
Entry time for the mine goes up with
increasing depth.
Decline road needs constant maintenance.
Break down of one machine blocks road.

13. Mine entry- Adit
Simplest mode of entry.
Feasible for ore body in hill.
Deposit is at higher level than
Ground.
Entry does not extend beyond
the ore body.
Rectangular in shape.
Near surface area has to be
supported.

14. ADVANTAGES - ADIT
 Cheapest
 Gentle slope in favour to
load.
 Costly machines like winder
etc are not required.
 Easy access for persons by
walking.
 Water drains out with gravity.
 Combination of adits provides ventilation.
 Track less & track mounted machinery to be used.
 Possibility of using surface equipment.

15. DISADVANTAGES - ADIT
Applicable for specific ore body only.
Only limited portion of ore body can be
mined.
Filling up of stopes are difficult.
Ore body
Adit
Outcrop
Mineable through Adit

16. ADIT 4 OF JADUGUDA MINES
1964,
• Used for
production of ore
• Intake for mine Air
2013
• Fitted with main
Mine fan
• Used as Emergency
Exit for mine

17. INCLINE
Entry for portion of ore body below surface
level.
Entry sloping downwards.
Incline equipped with track, steps, ladder
for movement.
Conveyance can move down by gravity.
Incline normally follow true dip, special
cases apparent dip.
Mouth of incline can be fitted with winder,
hoist etc.
Incline can be fitted with conveyor belt.

18. INCLINE ADVANTAGES
Easy to excavate.
Relatively cheaper.
Risk and hazard at the time of
construction is low.
Incline can be located in ore/ in foot wall.
Cross cut distances are short.
Maintenance of the fittings in incline is
easy.

19. INCLINE DISADVANTAGES
Excavation is slow.
Longer distance to be travelled for a certain depth.
Frequent maintenance of winder, rope haulage, rails
etc.
Handling material in incline is difficult and time
consuming.
House keeping of
the incline is difficult

20. SHAFT
Mine shaft is vertical entry for under
ground ore deposit
Can be circular, rectangular, square,
elliptical in cross section.
Suitable for deep seated, flat, incline ore
body.
Shaft Location is more flexible .
Can start from surface or under ground.
Need re-handling of material.

21. INCLINE SAHFT
Follows ore body so less development to access ore
body.
Easy sinking
Relatively shallow depth
Smaller requirements for shaft headgear and winder
installation.
Maintenance prone
Difficult in material handling
Longer length for same depth
Slow speed of excavation

22. VERTICAL SHAFT
Shorter length
Easy to maintain
Faster movement
Material movement is easy
Sinking risk high
Longer length of cross cut
Level mechanisation is high.

23. SHAFT ADVANTAGES
Shorter travel distance
Low energy consumption
Low maintenance
Stable entry.
High speed conveyance.
Minimum ventilation resistance.
Provides efficient manpower, ore hoisting
system.
Shorter cable, pipe length in shaft.
High level of automation is possible.

24. DISADVANTAGES OF SHAFT
Shaft sinking and equipping are costly.
Shaft can not be used unless entire system is
operational.
Risk for falling from height is high.
All fittings in the shaft has to be maintained
rigorously through out the year.
Special equipment is to be used in shaft sinking.

25. ADIT
ADIT
VERTICAL SHAFT
INCLINE
DECLINE
X- CUT
COMPARISON OF ENTRIES
OUT CROP

26. SHAFT HOISTING
• UPTO 120m DEPTH, HOISTING
THROUGH DECLINE.
• BEYOND 120m SHAFT HOISTING
SHAFT & DECLINE:
COMPARATIVE COSTS

27. DECLINE
SHAFT
SHAFT VS DECLINE

28. Deciding Parameters For Drive/Drift
• Location:
• Geometry of ore body
• Geological factors.
• Near by water bodies/excavations
• Water seepage
• Dimension:
• Dip of the ore body
• Size of the ore body
• Transportation Mining Machinery
• Rock mechanics properties.
• Layout of air and waterline.
• Operational :
• Material handling
• Method of mining
• Ventilation
• Support system
• Location of O.T
• supervision

29. Deciding Parameters For Ramp
• Location:
• Features of ore body/ other excavations
• Geological factors.
• Near by water bodies.
• Water seepage rate.
• Dimension:
• Mining Machinery
• Ore hauling system
• Rock mechanics properties.
• Layout of air and waterline.
• Lay out of Electrical Equipments and cables
• Drainage system.
• Operational :
• Material handling of ore
• Method of mining

30. RAISE
• Special purpose openings (ore passes,
ventilation raises , man ways) are similarly
located between levels.
• Raises are driven Manual ,by alimak , raise
borer or VCR technique.
• Incline entry in the ore body or out side
• Raise can be vertical or incline.
• Angle , dimension of raise is very important in
designing of raise

31. H.W. LODE
F.W. LODE
495 ML
555 ML
640 M
905 M
HEAD FRAME
HEAD FRAME
T
H
I
R
D
S
T
A
G
E
F
I
R
S
T
S
T
A
G
E
S
E
C
O
N
D
S
T
A
G
E

32. LAYOUT OF
NARWAPAHAR
MINE

33. STOPE DEVELOPMENT
STOPE IS A BLOCK OF ORE BOUND
BY:
 A DRIVAGE AT THE UPPER
LEVEL
 A DRIVAGE AT THE LOWER
LEVEL
 RAISES CONNECTING THE
UPPER &
LOWER LEVELS
METHOD OF MINING DECIDES
ADDITIONAL
DEVELOPMENT REQUIREMENT
i.e.
RAMPS & OT CHUTES
IT FACILITATES ACCESS & DRAWING OF ORE
FROM STOPES

34. STEPS OF WORKING
STEP 1 & STEP 2
Main Drive (Tramming Level)
Step - 1
Main Drive (Tramming Level)
Step - 2
Stope Raise

35. STEP 3 & STEP 4
Stope Drive ( 4.0m x 3.0 m )
815 M Level
6.0
m
Stope Drive Stipping
815 M Level
6.0
m
Rock bolts
Step - 3 Step - 4
Sill Pillar
Sill Pillar
Stope Raise

36. STEP 5 & STEP 6
1st. Slice of 2m high
815 M Level
6.0
m
Rock bolts
815 M Level
6.0
m
Rock bolts
Step - 5 Step - 6
Sill Pillar
Sill Pillar
Sand Fill 3m.
Stope Raise
Stope Raise

37. CUT AND FILL
SECTION

38. Upper Level
Lower level
Raise
Cut and Fill Mining Method

39. Ramp Length 400m.
DESIGN No. 1
SCHEMATIC DIAGRAM OF
HORIZONTAL CUT & FILL METHOD
A

40. Ramp Length =320m.
DESIGN No. 2
DESIGN OF HAULAGE RAMP

41. Most Precious thing
that comes out of mine
is “The Miners”