Mine Development
(MN-2006)
Mid Term – I
Sir Padampat Singhania University,
Udaipur, Rajasthan 1
Lesson Plan : Mid Term - I
Sl. Content No. of
No. Lectures
1. Introduction to primary and secondary mine development 3
2. Mine Entries: Choice, location and size of mine entries 2
Shafts, inclines, declines and adits; their merits and
3. applicability 2
4. Mine Structures: Construction and layouts of structures 3
5. Shaft insets, ore and waste bins, skip-pockets 2
Sir Padampat Singhania University,
Udaipur, Rajasthan 2
Mine Development
Mine Development: The operations involved in preparing a mine for ore
extraction. These operations mainly includes …
Tunneling
Sinking
Cross-cutting
Drifting
Raising etc.
Two types of Mine Development
• Primary and
• Secondary development.
The main difference between is the life expectancy of the development
Sir Padampat Singhania University,
Udaipur, Rajasthan
Mine Development
Primary Development :
• Long life and are item like shafts, decline and other mine access, main
tunnels, haulages, crosscuts, ore and waste passes, crusher chambers etc.
• It is permanent feature of the mine.
• Developed early in mine life,
• Relatively long life span.
Sir Padampat Singhania University,
Udaipur, Rajasthan
Mine Development
Secondary Development :
• Temporary in nature
• Associated with the needs of a particular production unit or units
• Consumed as production proceeds
• Lifetime for this type of development is 1 or 2 years or even less than this
Sir Padampat Singhania University,
Udaipur, Rajasthan
Mine Development
Mine development serves number of purpose, which include
• Accessing the mineral deposit
• Provision of accurate geological information to aid the production process
• Providing the accurate information on other technical needs such as
i. geotechnical characteristics of the rock
ii. water inflow rate
iii. ventilation pollutant inflow etc.
Sir Padampat Singhania University,
Udaipur, Rajasthan
Mine Development
Development requirement are influenced by number of parameters, some
important parameters are listed below :
• Ore-body type
• Ore-body depth
• Mining method selected
• Economics
• Ore-body extent
Sir Padampat Singhania University,
Udaipur, Rajasthan
Mine Development
Excavation method:
Development openings in mines can be excavated in one of two ways
• Drilling and blasting
• Mechanical excavation
Techniques are used for various types of development openings and have its
own advantage and disadvantageous.
Sir Padampat Singhania University,
Udaipur, Rajasthan
Access to the Mineral Deposit
The selection of the proper size, configuration, arrangement and type of opening
required to develop a new underground ore body is a complex and difficult
engineering problem. Each opening has it own characteristics and requires an
accurate evaluation of all factors that may affect the design to access the ore body.
The basic design parameters that should be considered are as follows:
• Lowest capital expenditure
• Lowest operating cost
• Safe and reliable operating system
• Flexible and efficient system
• Supports the mine planning
• Provides fast access to the ore body to promote early cash flow.
Sir Padampat Singhania University,
Udaipur, Rajasthan 9
Access to the Mineral Deposit
Some of the design criteria that need to be considered are:
• Geology and mineral resources
• Hydrology
• Depth of ore body
• Flexibility for changes to mine plan, mining method, or expansion of project
• Production tonnage requirements
• Geotechnical inputs
• Ventilation requirements
• Capital and operating costs
• Schedule completion i.e. commencement of cash flow
• Availability of skills and labour requirements
• Safety
• Productivity and management of system.
Sir Padampat Singhania University,
Udaipur, Rajasthan 10
Types of Entries to Mineral Deposits : Adit
Adit : Derived from Latin aditus, is an entrance to an underground mine which is
horizontal or nearly horizontal, by which the mine can be entered, drained of
water, ventilated, and minerals extracted at the lowest convenient level. In short it
can be defined as a level, horizontal drift or passage from the surface into a mine.
Sir Padampat Singhania University,
Udaipur, Rajasthan 11
Types of Entries to Mineral Deposits : Adit
• Adit is used when a deposit is at higher level than the general ground level and
outcrops , then the access is through rising roadways from the ground level.
Example Kurasia, Chirimiri etc. mines are approached by adits.
• Adits are used to exploration of mineral veins.
• Adits are driven into the side of a hill or mountain, and are often used when
an ore body is located inside the mountain but above the adjacent valley floor
or coastal plain. When the mineral vein outcrops at the surface, the adit follow
the lode or vein until it is worked out and in this case the adit is rarely straight.
• When adits is used for the extraction of ore, it is called drift mining.
• Adits can only be driven into a mine where the local topography permits.
• There will be no opportunity to drive an adit to a mine situated on a large flat
plain area. When the ground is weak, the cost of shoring up a long adit may
outweigh its advantages.
Sir Padampat Singhania University,
Udaipur, Rajasthan 12
Types of Entries to Mineral Deposits : Incline
Incline : An incline is a sloping road driven from the surface to the deposit through
the alluvium and the rocks overlying the mineral deposit.
An incline is usally steeply dipping at 1 in 4 or 1 in 5
Incline
Sir Padampat Singhania University,
Udaipur, Rajasthan 13
Types of Entries to Mineral Deposits : Incline
• When mineral bed are at shallow depth.
• Open at along the true dip of the deposit, sometime shape of the property
necessitate its drivage along an apparent dip.
• Mineral bed upto depth (vertical) of 200m can be approached by inclines.
• The size of an incline is usally 4.2m wide x 2.0m high for endless haulage, belt
conveyor or rope haulage
• When it is used for travelling the size is as small as 2.4m wide x 2.0m high
Sir Padampat Singhania University,
Udaipur, Rajasthan 14
Types of Entries to Mineral Deposits : Shaft
Shaft : A vertical openings sank into the earth’s crust in order to access mineral
resources which are too deep to mine economically using open cut methods.
The design parameters are based on depth of shaft, ore and waste tonnage to be
handled, shift handling (work force), materials handling, mining machinery
handling, ventilation requirements, capital costs, operating costs, and the selling
price of the mineral.
Shaft are generally circular in shape & the finished dia varies from 4.2 to 6.7 m.
Two shafts are separated by minimum 13.5m, generally 30 to 60m.
Each seam have atleast two openings (as per regulation),
Unless the two shaft are connected no development work are permitted under law.
One shaft for mineral winding and the other for ventilation , man riding, material
transport.
Sir Padampat Singhania University,
Udaipur, Rajasthan 15
Types of Entries to Mineral Deposits : Shaft
Schematic of head frame
1. hoist
2. cable
3. wheel
4. sheer
5. false edge
6. hoist room
7. mineshaft
Sir Padampat Singhania University,
Udaipur, Rajasthan 16
Types of Entries to Mineral Deposits : Shaft
Shafts are generally used for the following functions:
• Access an ore body
• Transport men and materials to and from underground workings
• For hoisting ore and waste from underground
• Serve as intake and return airways for the mine (ventilation)
• Provide a second egress as required by mining law
• Storage of nuclear waste
Sir Padampat Singhania University,
Udaipur, Rajasthan 17
Applicable Condition
Sir Padampat Singhania University,
Udaipur, Rajasthan 18
Comparison
Opening Selection Criteria Advantages Disadvantages
Highly skilled labour required
Quick access to deep ore body High labour cost
Steep dipping ore body Efficient at depths exceeding 500m High initial capital costs
Shaft Cheaper per metre as depth High maintenance costs
Deep ore body increases Require headgear Limited hoisting
Early return on investment capacity
Require constant power supply
Can be mined in the strike or dip
direction of choice Longer distance to ore body
Easy access to shallow ore body Only economical to 500m vertically
Flat dipping ore body Low initial capital costs (no Excessive travelling time to ore body
headgear) Trackless hauling is slow and
Ramp
Low operating costs Construction congested
Shallow ore body skills and equipment readily Heat pickup from rock over length
available
Slower return on capital invested
High hoisting capacity with Water handling can be problematic
conveyor belts
Sir Padampat Singhania University,
Udaipur, Rajasthan 19
Comparison
Opening Selection Criteria Advantages Disadvantages
Derailments
Shaft maintenance & repairs time
Flat dipping ore body Limited development to ore body consuming
Inclined
Shallow ore body Short ore pass system required Spillage cleaning is time
consuming
Limited hoisting capacity
Sir Padampat Singhania University,
Udaipur, Rajasthan 20
Mine Development
Mechanized mining excavation has the following advantages:
Higher advance rates/development rates
Smooth development profile and superior rock stability (tunnel boring machine
and mobile miner circular profile in particular)
Minimum ground support
Reduced over break
Less surface disturbance
Less noise
Lower running costs
Continuous haulage system such as conveyor
Automation haulage systems,
Less labour required
Automation
Precise direction control (laser guidance),
Safety (no explosive)
Sir Padampat Singhania University,
Udaipur, Rajasthan
Mine Development
Major disadvantages associated with mechanized mining excavation are -
Costly
Difficulty in dealing with variable ground condition
In hard & abrasive rock high rate off wear and tear on the cutters leads to
i. high operating cost
ii. long period of downtime for cutters
iii. Frequent replacement of cutters
iv. High maintenance cost
Sir Padampat Singhania University,
Udaipur, Rajasthan
Mine Structures: Construction and layouts of structures
Mine structure are constructed to service subsurface mining operation and is made up of
three groups distinguished by their location namely
i. Surface Plant
ii. Shaft Plant
iii. Underground Plant
Surface Plant : Consists of access roads and parking, transportation facilities, power supply,
service and maintenance building, mineral processing plant, bulk storage, waste disposal,
facilities for air, water and solids.
The surface facilities unique are the shaft collar, enclosure, headframe(dominant structure
towering over the rest of the surface plant, houses drive, idler sheaves connecting the shaft
conveyance to the hoist), bins and hoist house. In coal mining it includes tipple and mineral
processing facilities.
Sir Padampat Singhania University,
Udaipur, Rajasthan 23
Shaft Plant : Consists of the facilities installed for materials handling of the ore, coal or
stone associated waste and the means of transport for the miners and material. It also
include arrangement for ventilation, drainage, power supply and communication. In the
shaft sinking stage and the period of horizontal development underground before
connection to the second access opening is made, it is necessary that the main access serve
all function including providing fresh air and discharge exhaust air. When the connection
between the two surface has been completed then permanent arrangement has to be
made to meet all the development and exploitation requirement placed on the shaft.
Conveyances called skip are suspended in the shaft on wire rope, operated in balance with
one another i.e. one descends when the other ascends. Personnel and material are
transported in cage in tandem with skip or another shaft.
Sir Padampat Singhania University,
Udaipur, Rajasthan 24
Application of mine access alternatives:
a. Vertical shaft with hoisting: For deep horizontal (< 30o), vertical or steeply inclined (> 70o)
deposit, bad natural condition, high production, long life.
b. Inclined shaft with hoisting: For moderately inclined (30o to 70o), deposit, moderate
condition, low to moderate production life, shortens horizontal development and allow
exploration during sinking.
c. Slope or decline with haulage (conveyor or truck): For shallow horizontal deposits, good
to moderate conditions, moderate to high production, long life, can install rope hoisting
and use with rail haulage, limited to 12o with trucks and 20o with conveyor unless high
angle.
d. Drift or adit with haulage (conveyor, truck, rail etc.): For shallow, outcropping, horizontal
deposit or steeply deposit in area of high relief, varied conditions, high production, long
life
Sir Padampat Singhania University,
Udaipur, Rajasthan 25
Underground Plant: There is a group of specialized opening, underground plant, required at
the shaft like:
• Horizontal opening intersect with vertical ones
• Transition from haulage to hoisting occurs (this location is called shaft station)
At the junction of two different material-handling system, arrangements for fast, efficient, safe
transfer of material. Facilities on each level for at the shaft station to handle personel and
material.
Sir Padampat Singhania University,
Udaipur, Rajasthan 26
Shafts: A primary vertical or non-vertical opening in a mine -
• excavated from the top downward
• through mine strata
• used for ventilation or drainage and/or for hoisting of personnel or material.
Winze : A minor connection between different levels in an underground mine. When sunk
downward from a higher level it is called winze.
Raise is a vertical or sub-vertical opening in a mine that is excavated from the downward top
Important features :
• It connects the surface with underground workings
• Internal construction within mine connecting vertically separate workings as well as levels
• Important capital openings for deep mines
• Provide all the services for underground operation which includes:
i. fresh air to working face,
ii. transport of ore supplies,
iii. personnel transport,
iv. power,
v. communications,
vi. waste supply
vii. Drainage etc.
Sir Padampat Singhania University,
Udaipur, Rajasthan 27
Shaft Selection
1) The depth of the shaft has direct influence on the total time to develop a mine
2) Shaft sinking account upto 60% of the total development time
3) Proper selection of the shaft sinking method to
• Minimize sinking time and
• Ensure uninterrupted operation
4) Have to consider shaft diameter and hoisting depths requires consideration of future
mining needs
5) better to over design the shaft in the initial stage of the project life span
Sir Padampat Singhania University,
Udaipur, Rajasthan 28
Following need to be taken into account while designing the excavation :
• Site geology (including a description of the of the geological column, usually in a table
form identifying the rock strata then geotechnical parameters, groundwater levels
including water heads, inflow rates and chemical contamination)
• Determination of the shaft diameter,
• Choice of shaft sinking technology,
• Description of the shaft lining (list of lining section with their thickness details)
• Shaft foundation including their location and dimension, shaft collar depth, foundations,
thickness and material to be used (the type and number of openings with a description
of their function, dimension and elevation details),
• Shaft sump, depth structural characteristics pumping arrangement & cleaning system,
• Calculation of ground and water pressure acting on the shaft lining
• Time table of construction
• Cost specification,
• Engineering drawing etc.
Sir Padampat Singhania University,
Udaipur, Rajasthan 29
Shaft shape and diameter:
Numerous factors need to be considered such as:
• Shaft duties and purpose :
i. Rock hoisting
ii. ventilation and
iii. worker and materials transport.
single purpose or variety of purpose,
Quantities involved
• The amount of water to be handled,
i. number of pipes and the
ii. diameter of pipes are important parameters as is the method of hanging these
within the shaft
• Ground conditions
• Size of mining equipment to be handled by the shaft
• Expected lifetime of the shaft
Sir Padampat Singhania University,
Udaipur, Rajasthan 30
• The majority of shaft in modern mining are circular in shape because of
i. Inherent strength and
ii. Advantages of minimum perimeter for a particular cross-sectional
• Rectangular cross section common in past and more poplar within metaliferous mine.
• Other shape used such as square or elliptical
• Elliptical shaft used where a significant horizontal stress field acts in a particular direction
the major axis of the ellipse is aligned to the direction to enhance the shaft strength
Sir Padampat Singhania University,
Udaipur, Rajasthan 31
Shaft Lining
• Shaft lining support the shaft equipment and walls of the excavation.
• The minimum lining required to support the shaft equipment is about 200 mm.
• The thickness of the shaft lining depends on number of factors like ground pressure
acting on the circular shaft, vertical or hydrostatic stress etc.
• Water seepage into finished shaft causes corrosion of steel installation
• Controlled using polyethylene or other shat liners installed at the rock-lining interface
• The thickness of a shaft lining can be determined by
Sir Padampat Singhania University,
Udaipur, Rajasthan 32
Shaft Collars
• Upper portion of a shaft
• Anchored to the first footing and to the bed rock
• The size of the collar depended on the load in the immediate surrounding area from the
shaft & associated equipment. These load include winding equipment and associated
dynamic load loading impacting from surface facility
Sir Padampat Singhania University,
Udaipur, Rajasthan 33
Shaft Collars
Dimensions of the collar depends on
• Depth
• Cross section
• Thickness
• The function of the shaft
• Overburden rock
• Hydrological conditions
• Ground pressure
• Sinking method
• Structural factor
• Additional loading condition etc.
Sir Padampat Singhania University,
Udaipur, Rajasthan 34
Shaft Insets and Sumps
Shaft insets be designed to minimize airflow resistance.
Sumps: At the base of a shaft and at intermediate levels to minimize pumping. Periodic
cleaning be designed to increase the holding capacity of the sump
Sir Padampat Singhania University,
Udaipur, Rajasthan 35
