MNC526 : Elements of Mining Technology
Chapter 5 : Sustainable mineral development,
best practices and global initiatives
Mining activity is, by its very nature, environmentally invasive.
Mining causes substantial changes to the landscape, air and
water in the vicinity of operations, consumes large amounts of
energy and produces great quantities of waste – in many cases
as much as 99 per cent of the material originally excavated.
Sustainable Development:
• development that meets the needs of the present
• without compromising the ability and potential of future
generations
• to meet their own needs
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How To Achieve Environmental Sustainability
A. Conservation of Biological diversity
B. Maintenance of capacities to produce
commodities /Mineral/material and energy systems
C. Maintenance of ecosystem health
D. Conservation and maintenance of air, soil, water (quality and
quantity) and physical geology (including quality, quantity and
form).
E. Maintenance of contribution to global carbon cycle
F. Legal, institutional and economic framework to support
sustainable development.
How to do Sustainable Mining
Mining can become more environmentally sustainable
by
• developing and integrating practices that reduce the
environmental impact of mining operations. These
practices include measures such as
• reducing water and energy consumption,
• minimizing land disturbance and waste generation,
• preventing soil, water, and air pollution at mine sites,
and conducting successful mine closure and
reclamation activities.
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Sustainable Mining Contd..
• The principles of sustainable development involve
integrating economic activity with environmental activities,
social concerns, and effective compliance of statutory
provisions i.e. Govt. systems.
• although mining itself may occur on a relatively small land
area, the associated infrastructure and pollution from mining
activities have the potential to affect the health of
ecosystems and reduce their ability to provide the goods and
services necessary for human and environmental well-being.
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Sustainable Mining Contd..
• In order to be more environmentally sustainable, mining
operations are increasingly conducted in a manner that
minimizes their impact on the surrounding environment,
and leaves mine sites in an acceptable state for re-use by
people or ecosystems.
• A number of management strategies and technologies are
being developed and used by the mining industry to reduce
the environmental impacts of mining,
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Water
• Water is used in a number of applications at mine
sites. By diverting surface water and pumping
groundwater, mining operations can reduce the the
quantity and adversely affect the quality of water
available downstream for aquatic ecosystems and
other industrial and municipal water users, especially
in areas with arid climates.
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ENERGY
• Mining and metal processing can be very energy-intensive
processes. For instance, diesel fuel is used by trucks and
excavators during mining, electricity is used to grind ore/coal.
The extraction of fossil fuels (coal, oil, and gas), and the
construction of infrastructure required for energy generation
have their own environmental impacts, including the
production of greenhouse gases and increased risk of
environmental contamination along the energy supply route.
• Reducing energy consumption at mines can reduce greenhouse
gas emissions and extend the life of fossil fuel reserves in
addition to reducing operating costs and therefore the cost of
the commodity being mined.
• Mining companies are also exploring renewable energy sources
including solar power to reduce costs and reliance on external
energy sources.
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Land disruption
• mining activities use land at every stage of the mine cycle,
including exploration, construction, operation, closure, and post-
closure. Vegetation is cleared for the construction of buildings,
roads, and powerlines, open pits or tunnels are dug to gain access
to the ore/coal, and waste storage facilities such as OB dumps,
tailings ponds are expanded over the life of the mine, potentially
leading to habitat loss and deforestation.
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There are a number of ways to reduce the land-use impacts of
mining. These include
• reducing the overall footprint of the mining area,
• minimizing the amount of waste produced and stored,
• maintaining biodiversity by transplanting or culturing any
endangered plants found on site, and
• planning mines around existing infrastructure where ever
possible.
• Although current technology requires ores/coal to be
excavated, research in areas offer the possibility of mining with
minimal land disruption in the future.
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Reducing Waste output
Waste
• Mine waste includes solid waste, mine water, and air
particles, which can vary significantly in their composition
and potential for environmental contamination. In addition
to preventing soil, water, and air pollution, waste
management plans are required in order to select and design
appropriate storage facilities for the large volumes of waste
produced at most of the mine sites.
• It is generally recognized that preventing pollution is more
economic and effective by reducing environmental impacts
than cleaning it up later on (i.e., leaving a legacy of
environmental degradation for future generations).
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Methods for minimizing and eliminating wastes in the
production of minerals and metal commodities include:
– Using cleaner production techniques
– Environmental control technologies
– Using waste as raw material, and
– Reducing the amount of waste produced through process
re-engineering.
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Surface Transport Systems:
• Truck/Dump truck Haulage
• Conventional belt conveying System/In Pit Crushing and
Conveying(IPCC)
• Pipe Conveyor system
• Cable/Rope Belt Conveying System
• Integrated Skip Conveying and Crushing System
Truck haulage
• Deposits and overburden are carried from
the bottom to the rim of the open-pit mine by
trucks on unpaved haul roads.
• Transportation on slowly rising ramps with an
inclination of merely up to 4.6°.
• Therefore the haulage distance of truck traffic
is enormous.
• The trucks weigh at least 106 up to 260 tons
whereas the payload on each truck is
between 136 and 400 tons. In fact the
conveying ratio is quite moderate.
• The average travelling speed of the train-like
vehicle formation as shown in the figure is
about 15-20 km/h.
• A fleet of several vehicles and truck drivers
including maintenance equipment are
necessary
• The haul roads have to be renovated
frequently due to wear and the progress of
mining.
ThyssenKrupp Resource Technologies
• The crusher-station is located at the bottom or on an intermediate level of the mine.
Conventional Belt Conveying system:
• • Conveyor inclination of around 13° requires several belt sections arranged in a zig-zag route
Dumping station/crushing station is located at the bottom or on an intermediate
onlevel of the surface mine
mine benches (several transfer stations).
• • Utilization of proven technology with a moderate
Because of limiting gradient of 13 inclination, also available with DirectDrive
0 a no. of belt conveyors arranged in a zig-zag
technology from Siemens and TKIS
route on mine benches (several transfer stations)
• At transfer points intermittent bunkerage may be required
In Pit Crushing and Conveying(IPCC):
• IPCC systems are another alternative to conventional truck haulage which
has limitations because of longer haulage distance and in deeper mines.
• This consists of a gyratory, impact, cone, or jaw crushers to feed an
overland conveyor belt that transports material to the beneficiation plant
or to the overburden dump
• IPCC may have mobile or semi-mobile crushing systems. Mobile systems
are crawler mounted and are often fed directly by an excavator. These
systems are usually found in small open-pit mines or quarries.
• Semi-mobile systems are mostly based on gyratory crushers fed either
directly from trucks or from truck fed apron feeders. They can only be
moved with specialized equipment, hence the name semi-mobile. These
systems are suitable for mines with very large production tonnages.
In-Pit Crushing and Conveying (IPCC)
Pipe Conveyor:
In the pipe conveyor, the belt is converted into a cylindrical shape in order
to fully enclose the material being transported. Benefits of this are the
following:
• Completely eliminates spillage and is more environmentally friendly
• Allows for sharper vertical and horizontal bends because there is no
risk of spillage
• Can take a more direct path when navigating irregular terrain
reducing civil works
• Can climb slopes 50% greater than trough belts
• The belt can be looped and the underside can be set up to transport
material in the opposite direction
by TKIS inPipe Conveyor integrated with In Pit Crusher:
partnership with ContiTech and Siemens
• Stationary pipe conveyor system linked to a crusher station at the bottom of mine. The tail
station (tension station) is based at the bottom and the head station (drive station) is located
at the rim of the open-pit.
• Depending on the inclination the pipe section of the conveyor bridges is mounted
perpendicular across to the benches of the open-pit.
• Steep angle inclination is up to 35° .
• A service cab driven by a rope winch is provided for maintenance and inspection along the
structure.
crusher service cab
station head station
pipe section
tail station
Cable Belt or Rope Conveyor:
The cable belt is a conveyor system where the belt is supported between two
steel cables on either side. In this variation, the cables absorbs the driving
forces of the belt. These conveyor systems can be covered to avoid pollution
Important Features of Rope Conveyor:
1. Transports material on a flat belt with corrugated side walls.
2. The belt performs the haulage function and is driven and
deflected by a drum in the head or tail station.
3. The belt is fixed to axles arranged at regular intervals to support
the belt.
4. Running wheels are fitted to either end of the axles. These run
on track ropes with fixed anchoring and guide the belt.
5. The track ropes are elevated off the ground on tower structures
6. An innovative conveying system for difficult terrain
7. Reliability that spans large distances
8. Specially developed for handling materials of all kinds.
Rope Conveyor :
9. This system has shown itself to be unbeatable – even in
impassable terrain. It can cross obstacles such as rivers, buildings,
deep valleys or roads without any problem.
10. Provides handling capacities of up to 25,000 t/h while occupying
a minimum structural footprint.
11. Low space requirements are the key features of this product.
12. Rope span length of approx. 1 km possible
Integrated skip conveying and crushing system by
TKIS
drive station truck
• A rope-driven skip runs on track rails to lift up
the complete uncrushed payload of a haul ramp
truck to the integrated crusher station.
• The conveyor consists of two skips with a sheaves
loading volume of 160 m³ that lifts up the
payload on a wall-mounted steel track with skip
an inclination between 55° and 80°.
crusher
• The skips are counterbalanced one to each
other by a rope system via tackle sheaves.
The skips are travelling inversely on
dedicated tracks.
travel track
• Drive and crusher station are located on the
top of the open-pit, close to the rim of the pit. truck
• The truck discharge station is placed on the ramp
ground level.
loading
• Truck ramps are provided on both levels
station
(top and bottom of the open-pit).
• Truck haulage is substantially reduced in
amount of trucks as well as in travel
distance.
SUSTAINABILE TCHNOLOGY
IN SECL –
A Case Study
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Economization/Optimization in Power Consumption:
A. Operational
• Specific Power Consumption
• Specific Diesel consumption
Particular 2011-12 2012-13 2013-14
Sp. Power Consumption 5.43 5.32 3.00
(Sp. Consumption of electricity/Cum of composite
production of coal and overburden) KWH/M3
Sp. Diesel Consumption 0.41 0.35 0.20
(Sp. Consumption of Diesel/Cum of composite
production of coal and overburden)Litre/M3
The trend shows that there is a reducing pattern in Specific Power and Diesel
Consumption. This indicates that company is heading through a sustainable path.
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B. Technology Indicators
• Using new eco-friendly technologies like installation of Belt
conveyors from pit bottom upto loading point to the customer for
transportation of coal
• Expansion in capacity with environment friendly coal transport.
• Using higher capacity HEMMs, which produce less pollution on
per unit production as compared to low capacity variants.
• Using continuous cutting technology avoiding drilling and blasting
and finally avoiding crushing
• Adoption of New Methodology with continuous monitoring of
carbon emission
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Skip Conveyor by TKIS – Skip discharge and drive
station
Skip Drive station
1 of 2 Skips
Emergency or
redundant
truck ramp
Gyratory crusher
with feed hopper
Discharge and
overland conveyor
General benefits of steep angle conveying
compared to conventional truck haulage
Reduction of transport costs in open-pit mines
Reduction of operational and personnel costs
Reduction of investment costs over the time
Reduction of maintenance and road refurbishment,
Narrow one way roads instead of wider two way haulage roads
System also keeps on working under rough weather conditions (fog, snow,
rain)
Significant minimizing of noise, dust and CO2 emissions
Extensive automation of the conveying process is possible
Comparison of haulage systems
Stipulation: conveying capacity of 3000 t/h, elevation to 220 m, operation time
7860 h/a
Trucks Belt Conveyor MegaPipe Skip Conveyor
Max. inclination 4.6° 13° 26° 55°
Travel way (one way) (m) 2 831 1 044 701 281
Energy requirement (kWh/a)43 mil. 19 mil. 21 mil. 19 mil.
Fuel consumption (l/a) appr. 12 mil. - - -
CO2 emission (t/a) 32 726 17 141 19 802 17 411
Travel speed (m/s) 3.6 ÷ 12.5 4.0 3.3 1.9
6 x 1 470 4 x 630 2 x 1 500 2 x 2 000
Installed Power (kW)
= 8 820 = 2 520 = 3 000 = 4 000
Manpower (w/o
23 1 1 1
maintenance)
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Rough comparison of steep angle haulage
technologies
3000 mt/h, 7860 h/a, 220 m
50 3000
million
2831
45
43 2500
40
35
2000
33
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Results
25 1500 energy requirement kWh/a
CO2 emission kg/a
20 21 energy costs USD/a
1044 20
18.4 19 19 1000 travel way (one way) m
15 17 17
701
10
500
5 281
2.2 2.5 2.2
0 0
6x CAT 789D (4.6°) Belt (13°) MegaPipe (26°) Skip (55°)
Haulage
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General benefits of steep angle conveying
compared to conventional truck haulage
Reduction of transport costs in open-pit mines
Reduction of operational and personnel costs
Reduction of investment costs over the time
Reduction of maintenance and road refurbishment,
Narrow one way roads instead of wider two way haulage roads
System also keeps on working under rough weather conditions (fog, snow, rain)
Significant minimizing of noise, dust and CO2 emissions
Extensive automation of the conveying process is possible
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Comparison Between Carbon Emissions From Coal Mining
Through Conventional Methods And Surface Miner System:
CARBON
Sr. No. PROCESS EMISSION
CONSUMPTION
( CO2 in T)
A1 DRILLING
A1.1 ELECTRICAL (KWh) 1567873 1081
A1.2 DIESEL (Litres) 156034 366
A2 CRUSHING (KWh) 12930109 8916
A3 BLASTING (Kg exp) 3103667 1471
TOTAL-Conventional ( CO2 in T) 11834
B SURFACE MINER 1608814 3778
Emission Reduction per Annum
8056
(CO2 in T)
Percentage Reduction in CO2
68%
Emission
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