Rapid Environmental Impact Assessment Study for the Proposed Capacity
Expansion of Bauxite Mines from 3.0 MTPA to 8.5 MTPA at Baphlimali Plateau
Chapter-2
Proposed Mining and Sources of Pollution
2.0
PROPOSED MINING AND SOURCES OF POLLUTION
2.1
Introduction
This chapter deals with the geology of the mining lease area, exploration details,
evaluation of the deposit, estimation of reserves, method of mining, machinery,
phase wise mineral extraction details, details on infrastructure, various sources of
pollution and the control measures.
2.2
Description of the Mines
The general and technical details of the mining operations are given in
Table-2.1.
TABLE-2.1
DESCRIPTION OF MINES
Sr. No.
I
1
2
Parameter
General Mine Features
Latitude
Longitude
Site and its surroundings
3
4
5
Pre mining landuse
Distance from proposed refinery
Streams / Nallahs
6
Nearest stream / river
II
1
2
3
4
5
6
7
8
9
10
11
Mine Technical Features
Method of mining
Proposed Production from
mine lease
Expected total Overburden
Total ML area
Mineable Reserves
Extent of mechanization
Type of Blasting
Type of drilling
Power requirement
Source of Power
Water requirement
12
13
a
b
C
14
A
Water source
Waste water Generation
Domestic waste
Industrial waste
Mine water discharge
Waste Water Treatment
Sanitary waste
b
15
Industrial waste
Noise Levels
VIMTA Labs Limited, Hyderabad
Description
the
19o18' N to 19o22' N
82o57’ E to 82o59' E in Toposheet 65 I/15
Site is a hillock with plateau top, ground slope
varies between 1:40 and 1:5 and at few places
slopes are steeper than 1:10.
Barren and waste land
16.0-km (Aerial)
Nil on plateau top, except a few rain-fed run-off
channels
Khandabindha nallah, a major tributary of
Indravati River (0.5-km, N of plateau bottom)
Opencast mechanised mining
3.0 MTPA (Before expansion);
8.5 MTPA (Total after proposed expansion)
153.42 Million Tonnes
1388.74-ha
194.5 Million Tonnes
100%
Deep hole blasting with delay detonators
Down the hole drilling
3000 kW
From CPP of alumina plant
720 m3/d (Before expansion)
2000 m3/d (Total after expansion)
San river water
40 m3/d (Total after expansion)
220 m3/d (Total after expansion)
Nil
The sanitary waste from the mine service yards
is treated in Sewage Treatment Plant
Vehicle wash water and workshop wastewater
will be treated in oil water separator and sent to
STP
Maintenance of HEMM to keep the noise levels
<85 dB(A)
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Sr. No.
16
17
18
19
2.3
Parameter
Ground vibration
Solid waste generation
Fire Fighting System
Stripping ratio
(ore : overburden)
Description
Within the safe limits
Overburden – 6.2 MTPA
Adequate fire fighting systems will be provided
on all HEMM
1.4 : 1
Geology and Hydrogeology
2.3.1 Physiography
Baphlimali plateau forms a part of Eastern Ghat hills. The plateau top is generally
flat and the elevation varies from 990-m to 1093-m. The plateau is devoid of
vegetation in most part. The ground elevation in the plains is about 750-m.
2.3.2 Existing Drainage
The Baphlimali plateau top has a relatively flat relief with slopes towards the
fringes of the plateau.
The plateau top has no streams or nallahs, except the run-off of rainwater during
monsoon. A number of springs originate from the foothills of the plateau at about
100-150m below the plateau top. The streams originating from the foothills of the
Baphlimali Plateau have been assessed for its quality and quantity. These streams
originating from Baphlimali either join Khandabinda nallah on north or San nallah
on the south of the deposit.
River Indravati, the main water course in the region, flows in SW direction on the
W side of the deposit at a distance of 7.5-km. The Khandabinda nallah, a major
tributary of Indravati River, flows at about 0.5-km in N. San nallah is flowing at
about 7.5-km in S direction from the plateau.
Surface water flow measurements indicate that the flow is gradually decreasing
from December to April. Earlier, flow measurements indicate that the flow in
these streams decreases further and the minimum flow is observed during first or
second week of May. However, the streams are perennial in nature.
Quality of both surface water and groundwater is good without high concentration
of pollutants. The pre mining surface drainage pattern of the mine lease area is
shown in surface map under Figure-2.1.
2.3.3 Geology
2.3.3.1 Regional Geology
The lateritisation of the east coast bauxite deposits was developed at the expense
of gneisses and schists. The dominant rock assemblage in the region, comprise
khondalites (quartz-garnet-potash-feldspar-sillimanite gneisses with or without
graphite) and its variants. These are high grade metasediments of argillaceous,
arenaceous and calcareous nature. The other group includes charnockites
(hypersthene-diopside granulites) and its equivalents, porphyritic granite
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gneisses etc. of Precambrian age. The general stratigraphic succession is as
follows:
Recent alluvium and soil
Recent
Ferruginous and aluminous laterite and
Tertiary
bauxite (on hill tops)
------------------------------------Unconformity-----------------------------------Garnetiferous porphyritic granodiorite and
Precambrian
gneiss
with
later
leuco-granite
(Charnockite suite)
Garnetiferous
quartizite,
graphite
sillimanite - garnet B quartz gneiss
(Khondalite suite)
2.3.3.2 Geology of the Deposit
The deposit occupies the crest of Baphlimali Parbat, a hill in the Eastern Ghats.
The hill is essentially composed of khondalites with charnockites occurring in the
south-eastern part of the hill. The formations have NE-SW trend and steep southeasterly dips of 50-80 degrees.
The important characteristics in the profile of Baphlimali deposit are summarised
below:

Top soil is mostly lateritic in nature varying between 0-2m in thickness and
covers almost 50% of the plateau area.

The laterite is more ferruginous and siliceous at the top where it is hard and
has cloggy, cavernous look. It gradually becomes more soft with depth where
it is aluminous in nature grading into bauxite. The clay bearing areas and
clayey laterites, occurring on the surface, are marked by growth of dwarf palms.

The bauxite shows gradational contact with overlying laterite and has a fairly
sharp contact with the underlying partially leached parent rock.

Roof of bauxite, due to gradational contact with overlying laterite, is a
chemical boundary and thus becomes a function of cut-off grades adopted by
the user.

Floor of bauxite has a sharp contact with underlying partially lateritised
Khondalite (PLK)/partially Kaolinised Khondalite (PKK). The undulations on
bauxite floor are rapid and sharp as compared to those on the roof.

There are some occurrences of PLK/PKK mixed bauxite and also aluminous
laterite patches within the bauxite column as inside waste.

The average thickness of overburden and bauxite globally for the deposit is
estimated to be 9.84-m and 11.51-m respectively.

There is a gradual decrease in hardness and compactness of bauxite from top
to bottom.
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There are few small patches of no-ore zones (non mineralised areas) which have
been confirmed by drilling. These no-ore zones are formed either due to
exposures of Khondalite on the surface or due to non-enrichment of alumina in
the entire lateritic/ bauxitic column.

Geomorphology - Surface Features
The laterite cover occupies the crest of the hill between 990-m and 1093-m RL
with a relief of about 103-m, Baphlimali is characterised by a relatively flatter
profile when compared to other bauxite plateau in the east coast region. The
ground slope varies between 1:40 and 1:5. Slopes steeper than 1:10 are rare.
Nearly half of the peripheral length of the plateau (29.5 km) is marked by scarps
(2-17 m height) with an average of 8-m. The scarps are better developed in the
eastern side where the maximum thickness of bauxite has been observed. The
scarps are generally aligned sub-parallel to the strike of the formation. The
ground slopes do not show any diagnostic relationships with ore characteristics.
However, they may be broadly correlated as follows:
The surface of the plateau is largely covered with lateritic soil. There are,
however, a few impersistent narrow exposures of pisolitic laterite (essentially
ferruginous) dissecting the capping at places and a few weathered khondalite
exposures restricted to the high topographical zone. Some partially lateritised
khondalite patches (PLK) could be seen with laterite exposures. Most of the
scarps expose only the partial thickness of the laterite/bauxite column and a few
others do expose the PLK/weathered khondalite.
Bauxite is considered to have been derived by the in-situ chemical weathering of
the khondalites. It occurs as a gently dipping or near horizontal blanket capping
over partially lateritised or weathered khondalite. Both laterite and bauxite show
relict foliation
The average thickness of ore body is arrived at by weighting the thickness of the
bauxite zone indicated by exploration points spaced at regular grid intervals
against their areas of influence. Narrow discrete partings of non-ore intervening
with bauxite have been included in bauxite for practical considerations. Where
thickness is so high as to convert the quality of material into non-ore if combined
with bauxite, only one subzone, generally the top one, has been accepted as
bauxite. The reserves of zone below the non-ore partings have been estimated
separately. The various lithounits adopted for the current exercise are as follows:
DETAILS OF LITHOTYPES
Litho Unit
Number
1
2
3
4
5
6
7
Lithology
Soil and soil mixed laterite
Hard Laterite with very high
slilica
High silica aluminous laterite
Low silica aluminous laterite
Bauxite
PLK/PKK mixed with bauxite
PLK/PKK and Khondalite
VIMTA Labs Limited, Hyderabad
Thickness
Range (m)
0-2
2-5
Average
Thickness (m)
0.5
3
2-3
1-2
6-41
Deeper
Deeper
2
1
13
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The detailed description of different lithotypes is as follows:
Lithounits 1 and 2 essentially form a part of overburden at the top. Lithounit 3 is
predominantly occurring as overburden below the lithounit 2. However, there are
few occurrences of lithounit 3 within the ore column as inside waste. Lithounit 4
occurs equally as inside waste within ore column and as bottommost layer of
overburden just above the ore-roof. Lithounit 5 is typical bauxite and forms more
than 90% of the ore column. Lithounit 6 invariably occurs just below the ore
column within one to two meter horizon. However, there are few instances of
lithounit 6 occurring as inside waste within the ore column. Lithounit 7 is
essentially a bottom waste below the lithounit 6 and thus is not significant from
point of view of mining/ wining the ore.
From the above it is obvious that litho units 1, 2 & 7 are not expected to mix with
ore during mining. Thus litho units 3, 4, 5 and 6 are important for defining ore
column and mineable column in individual drill holes.
2.4
Exploration and Exploitation
Drilling is the most important exploration activity undertaken during this
exploration, especially since most of the deposit is covered under capping of soil.
The pattern and type of drilling for proving a given deposit depends on the
topography, shape, size, extent, compositional variation, attitude of beds and
structure of the deposit. Taking these parameters into consideration, scientific
drilling was adopted.
The lease area has been extensively explored in detail by Geological Survey of
India (GSI) (during 1976-77), Mineral Exploration Corporation Limited (MECL)
(during 1978-81), INDAL (during 1992) and MECL (during 1998-99) to establish
mineral reserves. Details of exploration carried in the lease area are described
below:
TABLE 2.2
SUMMARY OF TOTAL EXPLORATION WORKS
Sr. No.
1
Agency
GSI
Year
1976-77
2
MECL
1978-81
3
INDAL
1992
4
MECL
1998-99
VIMTA Labs Limited, Hyderabad
Summary of Works
Drill holes: 52
Meterage : 1445.65
No. Of drill hole samples : 1240
Drill Holes : 530 (504 vertical + 26 inclined)
Meterage : 17843.55 (16758.15 vertical + 1085.40
inclined)
No. of Samples : 21837
Deep pits : 33
Meterage : 955.40
61 m3 of trenching
341 samples studied for petrology & minerology
Moisture and Density determinations
Redrilling of 30 holes by vacuum suction located on MECL
bore hole points, meterage 792
Resampling of 6 nos. of MECL pits
Drill holes : 45
Meterage : 1228
No. of samples : 1209
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2.4.1 Exploration as done by MECL
Based on the resource evaluation studies done by GSI, MECL planned and
executed detailed exploration programme at the instance of Govt. of India. The
methodology followed by MECL has been described in the following sections.
2.4.1.1 Method of Exploration done by MECL
a) Topographical Surveying
Triangulation and levelling survey was carried out over the entire bauxite plateau
and a network of 26 Triangulation stations was laid down. All GSI bore holes
were also connected to these stations.
A central axial line and cross-section lines at every 200 m interval (or less in
selected areas) were laid from the nearest triangulation station. The survey grid
was connected to Survey of India Triangulation Station T-10 at 1093.22 m (Topo
Sheet No. 65 I/15). The base plan for geological mapping was developed on
1:2000 in three parts covering the entire plateau top.
b) Geological Mapping
The detailed geological mapping was done to demarcate:






Lithological boundaries;
Outcrops of laterite based on visual;
Bauxite estimation;
Clay estimation;
Khondalite (including Kaolinised and partially lateritised khondalites); and
Structural features, viz.
o Attitudes of foliation in khondalites and relict foliation
o Plunges of minor folds
Apart from visual examination, limited shallow pitting was also carried out to
demarcate contact between bauxite and non-bauxite.
c) Drilling
Since the experience with wet drilling in other East-Coast Bauxite deposits did not
yield acceptable core recovery, conventional rotary dry drilling techniques using
tungsten-carbide tipped casing bits (NX in first 5m and BX in the rest) was
adopted to ensure full recovery. Core by this method was obtained in the form of
powder or chips. Air flush coring method was used in a few cases where hard
laterite was encountered particularly in the top layers.
A total of 504 Vertical and 26 inclined holes were drilled covering 17,843.38-m
drillage. 33 deep pits were also used. The depth of vertical holes ranged from
18.65-m to 55.10-m and depth of inclined holes ranged from 24.50-m to
57.67-m.
After studying the lithomaps of pit walls, it was concluded that the bauxite grade
revealed in pits is inferior to the ones revealed in corresponding bore holes and
this dilution is mainly caused by fluctuations in ore-floor and partly by fluctuation
in ore-roof over the areal extent (2.5m x 2.5m) of the pit.
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2.4.1.2 Resource Evaluation by MECL
Surface geological studies and voluminous sampling data obtained from bore
holes, deep pits, trenches and scarps formed the basis for MECL to determine
spatial characteristics of Baphlimali bauxite & overburden and chemistry of
bauxite and associated rocks. These were used subsequently in estimating
reserves and grades of bauxite.
2.4.1.3 Results of Reserve Estimation by MECL
The overall in-situ reserves and grades of Baphlimali bauxite deposit following the
above procedure by MECL using chemical cut off at +40% Al 2O3 and -5% SiO2 has
been estimated as under:
Total surface Area explored: 9.466 km 2
Overburden: Mean Thickness is 9.84-m and Total Quantity is 153.33 MT
Bauxite:
Mean Thickness is 11.51-m and Total Quantity is 186.43 MT
Average Quality of Bauxite: Al2O3 -44.95%; SiO2 -1.9%; Fe2O3 -26.34%; TiO2 2.07%; and LOI -24.19%
The surface plan for the mine lease is furnished as Figure-2.1. The geological
plan for the lease area applied for renewal on 1:2000 scale is given as Figure2.2.
2.4.2 Geological Sections
A total of 41 vertical sections running at right angles to the general strike
(N40030'E) of Khondalite were drawn interactively on the graphic screen where
for each hole OB column, ore column and their respective grades were displayed.
One longitudinal section trending N40030'E was additionally drawn for evaluating
the mineral continuity. The geological sections drawn on 1:5000 are shown in
Figure-2.3.
2.4.3 Adequacy of Exploration Done
Based on the experience of a similar working mine now in operation, it may be
concluded that the level of exploration done is adequate for an investment
decision at Baphlimali Plateau. This is reflected from the fact that this working
mine was drilled at 200-mx200-m to 200-mx400-m grids at the time of
investment decision and the working experience has shown broad conformity with
subsequent phases of global estimation without any surprises.
It is thus clear that the present level of exploration in Baphlimali deposit by MECL
provides adequate confidence in taking an investment decision to develop mines
for supplying bauxite to the alumina plant, with a consistent quality.
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FIGURE-2.1
SURFACE PLAN OF MINE LEASE AREA
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FIGURE-2.2
GEOLOGICAL PLAN OF MINE LEASE AREA
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FIGURE-2.3(A)
GEOLOGICAL LONGITUDINAL SECTIONS OF MINE LEASE
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FIGURE-2.3(B)
GEOLOGICAL TRANSVERSE SECTIONS OF MINE LEASE
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2.4.4 Future Exploration
At the first instance the deposit, as a whole, needs to be covered by 100m grid
spacing to generate sufficient information necessary for basic engineering. This
permits block-wise estimates for the deposit for blocks of 100-mx100-m with
sufficient accuracy, and would help in drawing up an accurate enough mining
programme adapted to the deposit characteristics.
This step should be followed by a closer grid of say 25-mx25-m in the immediate
area of interest to generate short and medium term plans as the project
progresses. Smaller grid spacing, can only study a restricted area of the deposit,
but with greater accuracy. These should, therefore, be distributed in the areas at
least one and a half years ahead of mining faces in order to have advance
information before mining takes place in the area.
All the future drilling campaigns (Phases I, II & III) will need to be undertaken
concurrently at varying paces. No of holes required annually for Phase I & II
drilling is 123, based on a time frame of 2 years for Phase I and 5 years for Phase
II drilling. Phase III drilling should however be at a much faster pace and should
start one and a half years before start of overburden removal. This lead should
continue throughout so that advance information is available on small dimension
blocks. The annual meterage required to be drilled works out to 3,33,900 m.
2.5
Reserves
2.5.1 Categorisation of Reserves
Under UNFC classsification, the total deposit reserves need to be reported under
the following eight categories:
A Mineral Reserve
1. Proved Mineral reserve (111);
2. Probable Mineral Reserve (121 & 122).
B Remaining Resources
1.
2.
3.
4.
5.
6.
Feasibility Mineral Resource (211);
Prefeasibility Mineral Resource (221 & 222);
Measured Mineral Resource (331);
Indicated Mineral Resource (332);
Inferred Mineral Resource (333); and
Reconnaissance Mineral Resource (334).
2.5.2 Estimation of Reserves

Geological Reserves
Summary of global resources based on 2D kriging is given in Table-2.3. While
estimating grades from their accumulation, the kriging variance of the estimated
grade is computed as per standard method.
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TABLE-2.3
SUMMARY OF RESERVES OF BAPHLIMALI BAUXITE DEPOSITS
Over Burden
Sector
A
B
C (North)
C (South)
Total
Total
Area
(Km2)
1.18
4.49
1.65
2.46
9.78
Minera
lised
Area
(Km2)
1.17
4.28
1.57
2.42
9.44
Thickness
(m)
Tonnage
(Millioins)
Al2O3
SiO2
% Grade
Fe2O3 TiO2
8.23
8.84
8.93
7.64
8.55
18.28
91.64
26.59
35.51
153.42
37.24
36.69
36.96
36.35
36.67
12.06
10.84
6.91
10.76
10.14
Miner
alised
Area
(Km2)
1.17
4.28
1.57
2.42
9.44
Thickness
(m)
Tonnage
(Millioins)
Al2O3
SiO2
15.47
13.16
10.67
11.71
12.66
32.58
101.38
30.15
51.01
215.12
44.89
44.90
44.53
45.30
44.95
1.72
1.88
1.82
2.00
1.88
28.97
30.96
34.03
31.38
31.58
1.84
1.98
1.89
1.92
1.95
LOI
19.29
19.05
19.58
19.04
19.14
Bauxite Ore
Sector
A
B
C (North)
C (South)
Total
Total
Area
(Km2)
1.18
4.49
1.65
2.46
9.78
% Grade
Fe2O3 TiO2
26.65
26.31
26.78
25.74
26.28
1.96
2.17
2.10
2.14
2.12
LOI
24.24
24.16
24.06
24.27
24.19
A total of 215.12 Million Tonnes of Bauxite reserves (Al 2O3: 44.95%) have been
assessed in this mining lease area, with an estimated total overburden of 153.42
MT.

Mineable Reserves
The geological resources of the deposit have been presented in above sections.
The mineable reserves are different from and lower than in-situ reserves and are
essentially due to non mining patches, leaving out areas having high stripping
ratio (more than 2), loss of ore trapped in unmined peripheral barrier and losses
and dilutions during actual mining on account of undulations in floor and roof
outlines of bauxite layer. A detailed study has been made to estimate mineable
reserves for each block of 25 m x 25 m by modelling the ore body behaviour in
terms of roof and floor.
The total geological and mineable reserves of the deposit are given in Table-2.4.
For the purpose of estimation of reserves, the Tonnage Conversion Factors of 1.8tonne/m3 is applied. The summary of reserves (category wise) is given in Table2.5.
TABLE-2.4
MINERAL RESERVES AS ESTIMATED
Geological Reserves (MT)
215.12
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Mineable Reserves (MT)
194.5
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TABLE-2.5
CATEGORY WISE SUMMARY OF RESERVES
Geological Reserves
(Million Tonnes)
Proved
Probable
133.96 ( 111 )
81.16 (121& 122 )
Mineable Reserves
(Million Tonnes)
Proved
Probable
121.12 ( 111 )
73.38 (121& 122 )
Note: The figures in the parenthesis are UNFC codes
2.5.3 Anticipated Life of the Mine
The anticipated life of the mine is relative and would depend on the quantum of
production. The deposit has about 194.5 MT of mineable reserves of bauxite. With
the approved mining production of 3.0-MTPA, the life of mine will be about
65-years.
Proposed Bauxite excavation is 8.54 MTPA, after the mine got fully developed,
i.e., from 9th year of plant operation. During these nine years of production ramp
up about 37.54 MT of bauxite will be excavated. Balance 156.96 MT will last for
the next 18 years at 8.54 MTPA. Thus the deposit will have a life of 27 years.
2.6
Proposed Mining Technique
Mining is proposed to be done by trench method of mining, which is the most
suitable for such blanket type deposit with undulating floor. This method is being
followed at Panchpatmali bauxite mine of NALCO also and is quite successful for
such deposits. The mining technique is described below.
2.6.1 Topsoil/Overburden Removal
This operation is done in two phases, the topsoil removal and then lateritic
overburden waste excavation. Fertile topsoil wherever occurs is excavated
separately by scraping with dozer and the heaps so formed is lifted by loader
dumper combinations to be spread on top of backfilled areas for land reclamation.
Overburden is to be excavated after loosening by ripper dozer or blasting by a
combination of hydraulic shovel, loader, dumper combination. The overburden
waste is then backfilled into mined out areas as part of land reclamation scheme.
The scheme of backfilling is planned for the entire life of the deposit. During initial
three years backfilling is not implemented as mined out area is not available.
During this period, the overburden is dumped on southern part of the deposit,
and later re-handled gradually from 6th year to 18th year to backfill into mined out
areas. The process of rehandling overburden dumps may be expedited so as to
complete it before the scheduled period, as and when area for dumping is
available.
2.6.2 Bauxite Removal
In view of the special bauxite disposition character, the deposit is excavated by
trench mining method comprising of a number of parallel trenches with staggered
faces. Mining in each trench takes place in two distinct slices. The system of this
method is given below.
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Mass mining of bauxite top layer (Slice-1) (almost consistent thickness):
Bauxite is loosened either by ripper dozer or drilled & blasted. Excavated by
hydraulic shovel/loaders, dumpers and transported to the nearest In-pit crusher.
The average thickness of this Slice-1 is about 10-m.
Selective mining of bottom bauxite (Slice-II) (undulating floor): Bottom
bauxite is normally not very hard and does not need any blasting. It can be
excavated by a backhoe standing on the bench above. However, wherever it is
hard or compact it is loosened through ripping or blasting. The bauxite is then
loaded with the help of loader or back-hoe (if space is constrained) and
transported by dumpers to the nearest in-pit crusher. The average thickness of
this Slice-2 is about 4 to 5-m.
Ripper dozer of 770 HP is proposed to be used to rip open the strata and then
dozed to form a heap. Various studies carried out on Baphlimali hill have given
sufficient indication that 70% of the strata can be loosened by ripper dozer of
770-HP. Very hard patches of strata need to be drilled and blasted, some of the
soft areas in selective bottom bauxite can be straight away excavated without
either ripping or blasting.
2.6.3 Reclamation
Land reclamation envisages backfilling of overburden into mined out areas and
topsoil spreading evenly, plantation of local species is proposed after suitable
treatment, soil amendments and enrichment of reclaimed land.
A sketch indicating the various mining operations in an isometric view is
presented in Figure-2.4.
The proposed mining techniques to be adopted are given in the Table-2.6.
TABLE-2.6
PROPOSED MINING TECHNIQUES TO BE ADOPTED
Material
Overburden
Excavation
70% by ripping 30%
by drilling & blasting
Rehandling of
overburden from
external dump
-
Loading
100% by combination
of wheel loader and
Front shovel
Transport
100% by rear
Dumper
100% wheel loader
100%
Dumper
by
Top Bauxite
70% by ripping 30%
by drilling and
blasting
100% by combination
of wheel loader and
Front shovel
100% by rear
Dumper
Bottom Bauxite
30% by ripping 10% by
drilling
and
blasting/balance needs no
rock breaking
30%combination
of
wheel loader and Front
shovel 70% by back Hoe
100%
Dumper
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FIGURE-2.4
ISOMETRIC VIEW INDICATING THE VARIOUS MINING OPERATIONS
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2.7
Mine Development and Production
Mine production will proceed with the advance of trenches, each trench at
different floor level maintaining close to floor. Each trench will have about 80 to
100-m width. The overburden front is mostly planned to have an advance of
about 80-100 m ahead of bauxite front, overburden excavation is carried out in
single bench of about 8-m on an average, however bauxite excavation is
proposed to be carried out in two slices, the top slice (about 10-m thick) will
involve unhindered mass-mining, the bottom slice, usually about 4 to 5-m thick,
is required to be mined selectively to exclude the non-bauxite high silica zones on
the floor. At places with high bauxite thickness, the unhindered mining of bauxite
layer may be mined in two slices, so as to leave only about 4 to 5-m or even less
for selective mining.
The area around first mine cut will be developed to a width of about 1000-m, so
as to have about 10-12 trenches advancing parallel to one another. The semimobile crusher will be set up in the central trench so as to have equal distance
from the farthest trench. The second crusher will be located during the seventh
year of mine operation on the Northern part of the deposit. From 9 th year
onwards the two crushers together will deliver full production of 8.5 MTPA of
bauxite to the alumina plant. Each crusher will have a capacity of 4.25 MTPA.
The mine development involving excavation of overburden and bauxite for initial
period of five years is given in Table-2.7. The overburden excavated during the
first three years is totally dumped on the southern plateau top. The overburden
excavated in the fourth year is partly (2.10-MT) dumped in the designated OB
dumps and subsequently backfilled into mined out areas. The year-wise detailed
development and production schemes are described in the following sections.
TABLE-2.7
YEARLY EXCAVATION OF OVERBURDEN AND BAUXITE
Year of
operation
Overburden
Removal (MT)
Bauxite
Mined (MT)
1
2
3
4
5
6-8
9
2.14
1.00
2.15
3.10
3.02
21.78
6.95
1.24
1.60
3.08
3.70
3.98
23.94
8.50
Grade of
Bauxite (%)
Al2O3
SiO2
44.21
2.02
44.63
2.10
44.34
2.13
44.43
2.14
44.78
2.12
44.46
2.16
44.28
2.29
Cumulative
Bauxite (MT)
1.24
2.84
5.92
9.62
13.60
37.54
46.04
2.7.1 Year-wise Development and Production for the First Five Years of Operation
Year-wise detailed mine development drawings and excavation schedules are
prepared for the first 5 years. During the first five years 67-ha of area is
excavated of which 15-ha area will be backfilled and reclaimed. In the first five
years total of 11.41 MT of overburden will be excavated and during the same
period 13.60 MT of bauxite will also be excavated. Conceptual mine development
drawings at the end of 5th year of operations is given in Figure-2.5.
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2.7.1.1 Mine Development during First Year
During first year, apart from opening of the deposit, various construction
activities of buildings such as office, workshop, other facilities area, access road,
electrical transmission line and distribution network, water pumping, supply,
storage and distribution etc will be completed. During this period, 2.14 MT of
overburden will be excavated from an area of 14-ha and the overburden so
excavated will be dumped in a designated area on the southern part of the
plateau top. This will expose about 3.0 MT of bauxite for excavation from different
mine faces. Incidental bauxite that will be excavated during the first year will be
1.24 MT, which will be stocked close to the proposed Semi Mobile Crusher.
During this period a Semi-Mobile Crusher also will be installed at the floor of
bottom bauxite such that the hopper level and the floor of top bauxite are at the
same level.
2.7.1.2 Mine Development during Second Year
The second year of mine development coincides with the Alumina plant
commissioning. Excavation is carried out around the initial mine opening during
the second year.
The quantum of bauxite excavation during second year will be 1.6-MT. This,
together with the bauxite stockpiled during the first year (1.24-MT) totaling to
2.84-MT, will be crushed and conveyed to Alumina plant through a long distance
conveyor.
The overburden excavated during second year will be 1.00-MT with mine fronts
advancing westwards. The overburden excavated is planned to be dumped as in
the first year on the southern part of the plateau top since, sufficient mined out
area is still not available for backfilling of overburden. Additional 7.0-ha area is
exposed during the second year totaling to 21-ha (including 14-ha of the first
year).
2.7.1.3 Mine Development during Third Year
By this period, the Mine will be sufficiently developed to excavate the desired
capacity of bauxite. Excavation and mine advancement progress towards west in
parallel trenches following the bauxite floor.
The quantum of bauxite excavation during the third year is 3.08-MT, which will be
crushed and conveyed to Alumina plant through the long distance conveyor.
The overburden excavated during the third year will be 2.15-MT with mine fronts
advancing westwards. The overburden excavated is planned to be dumped as in
the earlier years on the southern part of the plateau top since, sufficient mined
out area is still not available for backfilling of overburden. Additional 14-ha area is
exposed during the third year totaling to 35-ha (including 21-ha of the first two
years).
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2.7.1.4 Mine Development during Fourth Year
Excavation and mine advancement continues in parallel trenches towards west
following the bauxite floor. The quantum of bauxite excavation during the fourth
year is 3.70-MT, which will be crushed and conveyed to Alumina plant through the
long distance conveyor.
The overburden excavated during the fourth year will be 3.10-MT with mine
fronts advancing westwards. The overburden excavated is planned to be dumped
as in the earlier years on the southern part of the plateau top. However, during
the later part of fourth year sufficient bottom bauxite has been excavated and
mined out area is available for backfilling. Thus, the overburden excavated from
then onwards will be backfilled into mined out areas. Additional 19-ha area is
exposed during the fourth year totaling to 54-ha (including 35-ha of the first
three years). Land reclamation of mined out area by backfilling is carried out over
an area of 5-ha during the fourth year.
2.7.1.5 Mine Development during Fifth Year
Excavation and mine advancement continues in parallel trenches towards West
following the bauxite floor. The quantum of bauxite excavation during the fifth
year is 3.98-MT that will be crushed and conveyed to Alumina plant through the
long distance conveyor.
The overburden excavated during the fifth year will be 3.02-MT with mine fronts
advancing westwards. The overburden excavated is planned to be dumped for
backfilling into mined out areas available after the excavation of bottom bauxite.
Additional 13-ha area is exposed during the fifth year totaling to 67-ha (including
54-ha of the first four years). Land reclamation of mined out area by backfilling is
carried out over an area of 10-ha during the fifth year, thus cumulative area
reclaimed at the end of fifth year will be 15-ha.
2.7.2 Proposed Rate of Production, when mine is Fully-Developed
The proposed rate of production of the mine, when the mine is fully developed is
8.5-MTPA of bauxite. The bauxite mine production will increase from the initial
1.24-MTPA to 8.5-MTPA during the 9th year to suit the requirement of alumina
plant. The Semi Mobile Crusher Plant–I (SMCP-I), which is designed for
production of 4.25-MTPA and is commissioned during second year, will be in the
central part. To cater to the increase of bauxite excavation beyond 4.25-MTPA, a
second Semi Mobile Crusher Plant–II (SMCP-II) of similar type and capacity is
planned and commissioned on the northern part of the deposit, during the
seventh year.
During the seventh year the mined out area is sufficient to re-handle the
overburden from OB Dumps and backfill into the mined out area around SMCP–I,
in addition the overburden excavated around the SMCP–II area on the northern
part will also be backfilled into the area available around SMCP–I.
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In subsequent years, the bauxite excavation from northern part will further
increase and in the ninth year both the working areas near the two SMCPs will be
producing 8.5-MTPA of bauxite, simultaneously excavating about 7.0 MTPA of
overburden.
2.7.3 Conceptual Production Plan for Tenth Year Onwards
Mine development/excavation will be stabilized from 9 th year onwards to excavate
8.5-MTPA of bauxite. Mine Closure plan at 27th year of working is enclosed as
Figure-2.6.
The mined out area corresponding to Crusher-I will initially advance westwards
and then towards south. Accordingly, the crusher is shifted to a location on the
Southern part of the plateau. Crusher-I will thus be handling all bauxite in
Central, Eastern and Southern side of plateau and Crusher II will be handling all
bauxite on the Northern and Western part of the plateau.
Due care has been taken during mine planning for proper blending from both
mining areas to meet the plant feed grade of bauxite.
Year wise Mine plans prepared indicate the area excavated in sequence for
overburden excavation, mass mining (of top bauxite), selective mining (of
bottom bauxite) and area backfilled by overburden waste. The block krigged
values provide data on estimates of overburden thickness, bauxite thickness,
quantity, its grade etc for each block of 25-mx25-m. Almost equal quantity of
bauxite needs to be excavated from both the mining areas, depending on quality
of each 25-mx25-m blocks, areas are selected for mining each year in a
sequence so that the required plant feed grade is met.
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FIGURE-2.5
MINE DEVELOPMENT PLAN AT THE END OF FIFTH YEAR OF OPERATION
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FIGURE-2.6
MINE CLOSURE PLAN
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2.8
Equipment for Ripping, Dozing, Drilling, Loading and Transportation
2.8.1 Mining Equipment
The mining will be done with 100% mechanized opencast mining. Proposed
mining equipment along with other auxiliary equipment are presented in Table2.8.
TABLE-2.8
LIST OF MINING EQUIPMENT
Sr.
No.
Description
Capacity
No. of Units
Existing
After
Approved
Proposed
Capacity
Expansion
(3.0 MTPA)
(8.5 MTPA)
2
6
1
Ripper Dozer
770 HP
2
Rotary Drills
2
3
3
Rear Dumpers
150-165
mm
85 T
50T(16)
12
4
11.0 m3
4(4.2m3)
2
5
6
Hydraulic front
shovels
Front end loader
Hydraulic Back Hoes
11.5 m3
11.0 m3
2(5.5m3)
--
3
1
7
Hydraulic Back Hoe
3.2 m3
2
1
8
Track Dozers/bull
dozers
320 HP
2(250-300HP)
4
9
wheel dozer
300 HP
1
2
10
Motor Grader
300 HP
1(150HP)
2
11
Water Sprinkler
16 KL
2(28KL)
4
12
Vibratory Compactor
10 T
1
1
13
Mobile Hydraulic Rock
Breaker
15-20T
1(100HP)
1
Remarks
For
excavating
overburden, bauxite
For Blast hole drilling and
production
For hauling ore from
mine faces to crusher
Loading of top bauxite
Loading of top bauxite
Loading
of
bottom
bauxite
Loading
of
bottom
bauxite from constrained
areas
road
maintenance,
stockpile
handling,
levelling in backfill areas
etc
maintenance
of
haul
roads, ramps and service
road
maintenance of roads
and connecting ramps
sprinkling on haul roads
and other dust prone
areas
consolidation on haul
roads
To break large boulders
2.8.2 Ripping and Dozing Equipment
As explained earlier sections, ripper dozer will be deployed in conjunction with
wheel loader/Hydraulic Front shovel at overburden, top bauxite and bottom
bauxite benches. Based on the hourly ripping and dozing capacity of 470-tph for
Baphlimali bauxites using 770-HP class of ripper dozers six number of ripper
dozers required have been computed.
2.8.3 Drilling Equipment
A drilling pattern of 5m x 4.5m has been proposed and an effective drilling rate of
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15 m/h has been assumed for arriving at number of drills. Based on the annual
tonnage to be handled by drilling equipment, 3 Nos of 150-165 mm dia drills will
be required. One drill is proposed to have standard mast height for deployment in
bottom bauxite and other drill of single pass-tall mast type for drilling in
overburden and top bauxite. This, however, will be further reviewed at
implementation stage, when rippability of the deposit is better understood and
firmly quantified.
2.8.4 Sizing of Loading/Hauling Equipment
The choice on size of loading and hauling equipment is primarily done by
considering the quantum of material handling. Total of bauxite and overburden to
be handled is about 15.0-MTPA. A mine with such high material handling capacity
has to choose the mining equipment adequately so that too many work fronts are
not required to be operated.
2.9
Blasting Details
Approximately, 30% of the excavation of top bauxite and overburden, and 70%
bottom bauxite, which cannot be dislodged by the ripper, will be drilled and
blasted. For effective blasting of the strata, explosive is required to be kept
suitably for some amount of confinement. Therefore, it is to be kept within drill
holes and after proper stemming and tamping, the explosive will be detonated for
explosion.
2.9.1 Blasting Procedure
A maximum of 10-m deep blast hole will be formed by the help of Rotary drill of
150 mm diameter and an amount of 70-kg explosive will be loaded per hole. The
stemming length of blast hole is proposed at 2.75-m and the balance is for
explosive column. The ratio of high explosive to AFNO has been kept at 1:3. The
explosives column is to be blasted under “V” type blasting pattern initiated by
detonator fuse, detonating etc.
2.9.2 Blasting Hours
Atmosphere is hot during day time and comparatively cold in evening hours. In
hot atmosphere, instantaneous emitted dust particles from blasting are supposed
to spread over a large area than cold atmosphere. Therefore, blasting hours will
be restricted to noon hours i.e., 12 noon at 2 pm.
2.9.3 Broad Blasting Parameters
Burden : Burden is the perpendicular distance form the hole to the nearest free
face in the direction in which the displacement is required to achieve the
maximum effect of explosive, the burden is required between 20-50% of the
bench height. For Baphlimali bauxite deposit, 45% is considered to be the most
optimum figure for medium hard rock, which is also based on field practice of
other bauxite mines in the Orissa state. 4.5-m of burden will be provided.
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Spacing: Spacing is the distance between individual drill hopes. It normally
varies between 1.0-1.3 times of burden. Depending upon the nature of the rock,
degree of fragmentation required and method of initiation, spacing is proposed to
be kept at 1.1 times of burden. A spacing of 5.0-m will be maintained.
Sub-Grade Drilling: To prevent the formation of toe on the bench floor, it is
necessary to drill a certain depth more than the height of the bench and this
additional drilling, generally called as sub-grade drilling and normally varies
within 8-10% of the bench height.
Stemming Length: Increase in stemming length, decreases fly rock and noise
but increases ground vibration level. For the area under reference, stemming
length is proposed at 20 times of the diameter where compressive strength of
rock is approximately 400 kg/cm2.
Delay Interval: Minimum delay interval between holes will be kept at 4.5-m per
meter of burden.
The broad blasting parameters for the area are summarized in Table-2.9.
TABLE-2.9
SUMMARY OF BLASTING PARAMETERS
Parameters
Bench height (m)
Burden
Spacing
Sub-grade drilling
Depth of the Blast hole
Delay interval (minimum)
Stemming Length
Explosive column length
High explosive column
ANFO column
Material factor
Loosening of rock mass per hole
Details
8 to 10-m
4.5 m
5.0-m
1.0-m
11.0-m
25.0-m
2.75 m
8.25-m
2.25 m
6.0 m
1.8 t/cum
Bench Height x Burden x spacing=
9 x 4.5 x 5.0 = 202.5 cu.m
= 202.5 x 1.8 = 365 T
2.9.4 Type of Explosives
The most common type of explosives, which are readily available will be used in
the mine. The explosives will be:
1.
2.
Nitroglycerine based gelatinous explosives; and
Ammonium Nitrate Fuel Oil mixture (AFNO).
AFNO is an explosive formed by ammonium nitrate (94.0%) with diesel (6.0%)
as diesel oil. Ammonium nitrate is easy to handle and stable. It will be mixed
with diesel oil at site to produce the explosive mixture just prior to blasting.
Combination of these two types of explosives will be best suitable for effective
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blasting in the area. The annual consumption of explosives is given in Table2.10.
TABLE-2.10
ANNUAL EXPLOSIVE CONSUMPTION
Details
Ammonium Nitrate (AN)
Diesel Oil/Fuel Oil (FO)
High explosive
Detonating fuse
Ordinary detonators
Safety fuse
Detonating relays
Quantity
540 tonnes
40 KL
190 tonnes
220000 m
700 Nos.
2100 m
4125 Nos.
2.9.5 Storage of Explosives
Proper storage of explosives and accessories is important:



To ensure that these materials are kept out of the hands of unauthorized
persons (including anti-social elements);
To reduce the hazards of accidental explosions (due to unsafe and wrong
handling);and
To maintain them in good condition for use.
The capacity for storage to be provided will depend on estimated rate of
consumption of explosives. The magazine will be located at SW lobe of central
part of plateau.
The explosives will be stored in approved magazines, licensed by Controller of
Explosives, Nagpur. In addition, permission will be taken from Chief Controller to
use ANFO in the mines. The explosives will be transported using explosive van of
10-T capacity under the supervision of a competent person. Ammonium nitrate is
mixed with diesel oil with strictly safety precautions under the supervision of
competent person. All safety Rules and Regulations are followed while storing and
transportation of explosives. The magazine to store the explosives will have a
capacity of 25-tonnes.
2.10
Bauxite Crushing and Transportation
2.10.1 Crushing
The ROM bauxite needs primary crushing at the mine before transportation to the
alumina plant at Doragurha. It is proposed to have conveyor transport for
Baphlimali bauxite plateau. Primary crushing is necessary at the mine, while the
ROM bauxite is likely to have a size of 1000 mm.
The crushing system during initial years will consists of one Semi Mobile Crusher
(SMC-I) with a capacity of 4.25 MTPA. Later, during the 7th year of mining
operations, a second Semi Mobile Crusher (SMC-II) with same capacity and type
will be installed on the northern plateau. Thus, 8.5-MTPA of Bauxite to alumina
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plant will be mined, crushed and transported, considering alumina plants average
requirement of 7,08,332 tonne/month.
2.10.2 Crushing System
The flat topography of Baphlimali Plateau with its large areal extent suggests the
use of a crushing system which moves with the advancing mining faces. It was
therefore decided to make a comparison of fixed Vs mobile types of crushing
systems and it is proposed to use Semi Mobile Crushing Plant (SMCP), to have
advantages of mobility of system.
Semi-mobile Crushing Plant (SMCP)
Each SMCP consists of the following main equipments:





200 tonne capacity receiving hopper;
Apron feeder whose speed can be adjusted to control feed rate to the plant,
based on feed rate from mine;
Toothed double roll crusherl
Collecting belt conveyor to receive crushed ore, and feeding to bridge
conveyor whose length is to be adjusted based on the position of semi-mobile
crushing plant; and
Shiftable/ Extendable conveyor from SMCP to loading station.
The crushing equipment will be installed on a structure which is rendered mobile
by mounting on skids.
2.10.2.1 Description of SMCP
The description given here covers the system from ROM hopper to discharge end
of bridge conveyor for transporting crushed bauxite to loading station.
The ROM bauxite from mine is hauled by dumpers (85-T class) and discharged to
ROM Hopper. The inside of the hopper is lined with rails all around to withstand
impact/wear caused by discharge of bauxite boulders. In case larger/oversize
boulders (+1000 mm) are also dumped in to the hopper, these are likely to get
stuck at discharge point of hopper and may block the feed to Apron
feeder/crusher. A fixed type Rock breaker is provided at the crusher hopper to
break such boulders on Apron feeder and thus ensure free flow of bauxite to
primary crusher. However, mine will ensure that no oversize boulders of bauxite
are fed to the plant.
Water sprinkler arrangement is provided to suppress the dust generated around
the crusher area. Apron Feeder below the ROM hopper is of variable speed type
and its speed is adjusted to maintain uniform flow to Primary crusher based on
feeding rate of bauxite from mine. The Apron feeder is of robust construction and
can withstand impact of large boulders of bauxite discharged by dumpers from a
height, when the hopper is empty.
The Primary Toothed Roll Crusher has a gap setting of 150-mm between the rolls
during normal operation. However, this gap can be adjusted from 50-mm to 150mm. The rolls are fitted with replaceable wear-resistant teeth. The crusher
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reduces the size of bauxite from ‘D85’ of ‘-800mm’ to ‘D85’ of ‘-150mm’.
Toothed double roll crusher discharges the crushed bauxite to belt conveyor,
which in turn feeds to bridge conveyor. Bag filter type dust collecting system
mounted on belt conveyor will collect dust generated by discharge of crushed
bauxite on it. An EOT crane of 30/5 T capacity is provided for maintenance of
equipment. The equipment mentioned above except the bridge conveyor will be
installed on a structure rendered mobile by mounting on skids. Each crusher will
operate at 780 tph, but the crushers will be designed at 950 tph. Thus both
crushers together will operate at 1560 tph and will be designed for maximum
capacity of 1900 tph. The design margin is kept 20% higher to obtain an average
capacity of 1560 tph, which is required to meet the plant feed requirements.
2.10.3 Bauxite Transportation to Alumina Refinery
Based on various alternative modes of bauxite transport, it is proposed to adopt
transportation by single flight (without any transfer points in between) covered
conveyor from mine to plant. The conveyor is planned for a carrying capacity of
1560 TPH operating in three shifts per day and with 304 effective days of
operations in a year. The conveyor starts from the Semi mobile crusher located
on Baphlimali hill and is routed downhill over a distance of about 20-km to the
storage yard at the alumina refinery.
The conveyor connects loading point (altitude 1,000m) on the plateau top with
transfer tower-I (Angle Station) of Alumina plant at an altitude of 800-m. It would
follow the most favourable path determined by topographical maps and survey of
the region.
2.11
Mining Details
2.11.1 Mine Environment
The post mining configuration of the mining area will appear like a bowl shape
surrounded on all side by high walls. The mined out areas will largely be filled by
the over burden waste. Post mining operations, the profile of the plateau will be
changed and the plateau top will be lowered by 10 to 12-m.
2.11.2 Mine Drainage
One rain fed runoff is passing along the centre of southern part of the plateau.
Two smaller runoff streams are also passing through the plateau. These exist only
during monsoon season only and are not perennial sources. During mining
operations, the runoff stream will be initially diverted eastwards and later, the
runoff stream will not be in existence.
Some other streams and rills originating from the foothills of the Baphlimali
Plateau either join Khandabinda nallah on north or San nallah on the south of the
deposit. These will not be disturbed during the mining operations.
Groundwater level is at about 100 to 150-m below the plateau top. It is assessed
that the groundwater table is not likely to be intercepted during the mining
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operations up to bauxite-bottom, as the mining operations will be restricted to
only 25 to 30-m.
In addition to the mined out area being backfilled, parts of these areas are
proposed to be used as temporary water storage reservoirs to tackle direct
precipitation of rainwater in the active mining area. The floor of bottom bauxite is
not flat and has varying slopes on which the reservoirs are to be built. These
reservoirs will have a limited capacity and may be considered as short term
settling ponds for rainwater. The water stored in these reservoirs is most likely to
seep through the sub-stratum, which is sufficiently porous and water table is
much below the plateau top. Hence, further handling of the accumulated water is
not envisaged.
2.11.3 Exploitation and Utilization of Mineral
Maximum conservation and optimum utilization of mineral is the mission of the
mines management. The mine is captive to the Utkal Alumina Refinery and
therefore, entire mined out mineral will be consumed in manufacture of alumina
at the refinery site.
2.11.4 Waste and Sub-Grade Mineral Management
The lateritic overburden waste overlying the bauxite layer on plateau top has an
average thickness of about 8.0-m. The mining scheme envisages removal of
overburden waste and to use it for backfilling mined-out areas after bauxite
excavation in that area.
When the mine is fully developed to produce 8.5 Million TPA of bauxite, about 6.2
million TPA of overburden is required to be excavated. This overburden will be
dumped evenly throughout the mined out area, so as to regain the earlier
topography.
The overburden excavated during the initial years of mining needs to be stored
outside the active mining area, but within ML area only, until sufficient area is
made available for backfilling. As per the mining scheme proposed, backfilling
area is available from the fourth year. The quantity of overburden excavated prior
to commencement of backfilling will be about 7.39-MT, which needs to be
dumped/ stored outside active mining area (in ML area).
In order to facilitate rehandling of OB storage area later and from aesthetics point
of view, it is proposed to limit the height of these initial dumps to a maximum of
10-m. This will require an area of about 50-ha, considering the compacted
density of overburden at 1.65 t/m3. (compaction to about 80% of loose density).
The most suitable location for these overburden dumps is found to be on the
southern part of the plateau. This location has been selected because of
availability of sufficiently large area taking into account the direction of mine
advance, and the lead for rehandling and backfilling into mined out areas. The
overburden dumping is planned in two dumps leaving sufficient space in between
to allow the water to flow along its natural course, as there is a rain fed drainage
passing along the centre of southern part of the plateau.
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2.12
Reclamation and Afforestation Programme
2.12.1 Reclamation
It will not be possible to entirely restore the mined out land to its pre mining
natural conditions. It is envisaged to reclaim the mines once the available
reserves are exhausted suitably by way of plantation, creation of water reservoir
etc. Reclamation of mined out land is necessary for restoring the aesthetic beauty
of the area and also for putting the land back to better use.
The basic scheme for backfilling of overburden into mined out areas shall be to
regain the earlier surface profile, as far as possible. However, the void created by
the removal of bauxite layer cannot be entirely compensated by the dumping of
overburden and there is a likelihood of the topographic level going down on an
average by 10-m.
The aspect of varying thickness of excavation is taken into account while
computing the amount of overburden backfilled. The total tonnage of overburden
to be accommodated in each block of 25m x 25m is estimated from the area
available for backfilling and the combined excavation thickness of bauxite and
overburden in each block, using the tonnage factor of 1.65-t/m3 for compacted
overburden. Backfilling is carried out upto the mine boundary and peripheral
edge, leaving reservoirs at places where the depth of excavation is high. Direct
filling from OB front will resume from 4th year and rehandling from initial
overburden dumps will resume from 7th year onwards.
Topsoil would be utilised for intensive plantation and greenbelt development in
the non- mineral bearing areas, along haul roads, ultimate limit of benches and
all along the plateau periphery.
The overburden stored on the southern part of the plateau is envisaged to be
excavated gradually from the 7th year of mining upto the 18th year and backfilled
into mined out areas. Thus, at the end of 18 th year, all the overburden from these
dumps shall have been cleared. The re-handling from OB storage area has been
planned as a gradual process considering the area available for backfilling.
Apart from the above measures, entire overburden generated from the 7 th year
onwards will be utilised for concurrent backfilling.
2.12.2 Afforestation
Worked out pits would be suitably reclaimed by way of plantation and
afforestation. Plantation and greenery development will also taken up along lease
periphery, Plateau periphery, along haul roads and also in patches of area
identified for the purpose. For re-vegetation, plants and saplings as per soil
characteristics and site conditions are being selected in consultation with forest
department. In order to facilitate the proper growth of vegetation, suitable
measures like preparation of seed bed with suitable amount of fertilizers and
treatment with mulches have also been taken up. Vegetation cover around the
mine workings helps in dust control, enhancement of aesthetic beauty,
minimising run off and reducing noise.
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The afforestation will be carried out along the periphery of the lease in safety
zone, which will be of 15-m wide. Afforestation will also be carried out in
reclamation areas. The plantation, which is not surviving, shall be replanted
periodically prior to rainy season. The density of plantations will be about 1500 to
2500 saplings per hectare. The afforestation program proposed is as given in
Table-2.11.
TABLE-2.11
AFFORESTATION PROGRAMME
Period
At the
At the
At the
At the
At the
At the
Total
end
end
end
end
end
end
of
of
of
of
of
of
5th year
10th year
15th year
20th year
25th year
mine life
Backfilled
and
Reclaimed
Area (ha)
Number of
saplings
15.0
100
100
100
100
185
600
30000
200000
200000
200000
200000
370000
1200000
Greenbelt along
Periphery of ML
(Safety Zone)
Area
No.
(ha)
saplings
6.0
12000
8.75
14000
8.75
14000
8.75
14000
8.75
14000
41.0
14000
41.0
82000
Total
Plantation
42000
214000
214000
214000
214000
384000
1282000
2.12.3 Land Use Pattern
The present land use pattern in the lease area (prior to commencement of mining
operations) comprised of waste / barren land. Presently, the land is not is used
for any purposes. The details of the land use at various stages of the mining
operations are given in Table-2.12.
TABLE-2.12
LANDUSE PATTERN IN MINE LEASE AREA
Sr.
No.
Details
1
Area excavated or in active
mining
Storage for topsoil
Storage for overburden
Mineral storage
Infrastructure
Roads & Conveyor
Railways
Tailing Pond
Greenbelt including green cover
in Open Lands
Township area
Others (Explosive magazine)
Open / Vacant / undisturbed
Land
Reclaimed area of mined out
area
TOTAL (Excluding Sr. No. 13)
2
3
4
5
6
7
8
9
10
11
12
13
Existing
Land Use
-
Area (ha)
After 5 After 10 After 15
Years
Years
Years
67.0
277.0
487.0
At the end of
Mine Life
850.0
-
-*
50.0
1.0
11.0
10.0
6.0
-*
50.0
1.0
11.0
10.0
14.75
-*
50.0
1.0
11.0
10.0
23.5
-*
0.0
1.0
11.0
10.0
41.0
1388.74
0.5
1243.24
0.5
1024.49
0.5
805.74
0.5
475.24
-
15.0
115.0
215.0
600.0
1388.74
1388.74
1388.74
1388.74 1388.74
Note: *: Topsoil will be stored within the area to be excavated and concurrently used for reclamation
of the back-filled area. Accordingly, it is not quantified separately.
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2.13
Mine Closure Plan
Since, this is a proposal prior to opening up of the mine this is a Progressive Mine
Closure Plan and is described in the following sections.
2.13.1 Mined Out Land
It is proposed to reclaim the mined out area by backfilling of overburden waste in
the mined out area in a progressively sequential and scientific manner over the
life of the mine as depicted in year-wise mine development plans and mine
closure plan. In addition, the reclaimed land will be planted with native species,
so as to bring the original flora and & fauna back.
This will be done in the following manner:




Dump the overburden into mined out area in a layered manner;
Doze it to make it even or sloping as per earlier topography;
Cover it with fertile topsoil; and
Plantation on top.
This is considered as the most accepted and environment friendly manner of
disposal of overburden and reclaiming the mined out land.
Post plantation practices such as preparation of tree basins, partial trimming,
plant protection from insect & pest attacks, application of fertilisers & manures to
fulfil its nutrition requirements etc would be regularly taken up. In addition to
above, the practice of bio mass creation within plantation shall also be taken up
to enrich the soil by the nitrogen fixation. Manure would be provided by dried up
bio-mass decomposition etc. The summarised account of reclamation is given in
Table-2.13.
TABLE-2.13
THE SUMMARISED ACCOUNT OF RECLAMATION
Year of Working
1
2
3
4
5
6-10
11-15
16-20
20– Mine Life
Total
Opened up Area (ha)
14.0
7.0
14.0
19.0
13.0
210.0
210.0
210.0
153.0
850.0
Reclaimed Area (ha)
0.0
0.0
0.0
5.0
10.0
100.0
100.0
100.0
285.0
600.0
2.13.2 Waste Management
At Baphlimali bauxite deposit total waste rock generated over the life of the mine
is 139.23 MT while the quantity of bauxite mined is 194.5 MT. The waste rock is
lateritic in nature and is not known to contain any toxic or hazardous chemicals.
The overburden waste is proposed to be backfilled into mined out areas to reclaim
the land as described earlier.
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2.13.3 Topsoil Management
In view of the importance of topsoil in maintaining the fertility of the land, during
mining, the topsoil (wherever it occurs) will be first scraped out and preserved
separately. The total quantity of the topsoil in the ML area is estimated as
30 MT. After systematic backfilling of overburden waste into mined out areas, the
following measures are proposed:



Topsoil spreading evenly over the backfilled areas to regain the fertility of the
land;
Suitable soil treatment and making it worthy for plantation; and
Plantation in the reclaimed areas.
2.13.4 Tailing Dam Management
As no beneficiation of mineral is envisaged at mines, no tailing dam is envisaged.
2.13.5 Infrastructure
The mine is proposed to have two Semi Mobile in pit Primary Crushing units near
the mine working faces. The Alumina plant, which is located on SE of the deposit,
is connected to the mine by a 20-km long single flight long distance conveyor for
transport of bauxite from the mine. The Explosive Magazine is located on one of
the lobe of the plateau on the South Western side.
The various other mine facilities (Site Services) provided at plateau top for the
smooth operation. These facilities are located in an area of about 11-ha at the
eastern end of the plateau at 1010-m elevation. The approach road to the mine
on hilltop from the alumina plant is routed along the eastern foothill towards the
south eastern side of the hill gradually.
In view of the continuous plantation and concurrent reclamation of the mined out
area, on mine closure the entire mining complex would turn out with greenery of
plantation all around the plateau top interspersed with a number of small
reservoir ponds all over. It is envisaged that when the mine is closed, most of the
structures will have out lived their life. Any structure, which is not required at the
site after the mine closure can be dismantled or relocated to other group
company sites for further use. Some of the civil structures will be dismantled and
razed to the ground.
2.13.6 Disposal of Mining Machinery
Most of the mining machinery would have reached to end of their useful life.
However, some of the equipments, which are still in operating condition, are
proposed to be shifted to other locations or they will be sold off as second hand
mining equipment.
2.14
Mine Support Facilities and Utilities
The following facilities are proposed at Baphlimali plateau top:
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




















Mine office for general administration;
Workshop and Stores (servicing and repairing shop);
Explosive Magazine;
Ammonium Nitrate Storage;
Mixing shed for ANFO;
Pit Office including field maintenance shed;
Rest shelters;
Fuel filling station and lubricant store;
Fire Station & First-Aid Station;
Sample Preparation Station;
Canteen;
Training Centre;
Main Receiving Sub-station;
Environment, Occupational health & Safety;
Water Storage, treatment and pumping facilities;
Check-post & Rest rooms;
Storm water drains;
Magazine (for storage of High Explosives);
Toilet facilities;
First aid station (s); and
Weigh bridge.
The facilities will be located at hill top on one of the extension lobes of eastern
periphery of the plateau, approximately midway between its northern and
southern extremities. This lobe is nearly devoid of bauxite mineralisation, and is
separated from the main mining area by a buffer of trees. All the facilities have
been located within an area of 11-ha.
2.14.1 Access Road
The access road to mines starts from Tikiri-Kashipur road junction via refinery
site and Dongasil village upto mine top. From Kupakhal situated just downhill of
Baphlimali deposit, the road rises along the eastern escarpment to the entry gate
of facility area at 1010-m contour. The road also passes close to the water intake
point at Katkhal crossing the San River.
The road distance from mines top to the alumina plant is approximately 30-km.
The total length upto Tikri-Kashipur Road junction is 37-km of which about 14-km
will be totally new construction. This road will have a width of 9.0-m.
2.14.2 Work Shop Servicing and Repair Shop
A floor area of approximately 500-m2 covered by the structural steel construction
will house for servicing and repair centre.
2.14.3 Fire Station/First Aid Room
A fire station with all the fire fighting equipment and a fire tender will be
stationed at the mines facilities as per the safety norms. Integrated in the same
building a first aid room with attending doctor will be stationed.
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2.14.4 Electric Power
Since the mine will have mostly diesel operated mobile mining equipment, the
electrical load will be mainly on account of crusher system, workshop equipment,
mine lighting, office lighting and miscellaneous loads like water pumping etc. The
electric power required for mine to plant long distance conveyor has been
included in the alumina plant electric load. The power required for the Baphlimali
mine for all the above activities after expansion to 8.5-MTPA will be about 3000KW. The power requirement at 3.0-MTPA production level is estimated as about
1000-KW
The power will be drawn at 33 KV from alumina plant over a distance of 20-km
and received at electric sub-station located near conveyor loading station. Apart
from this, the mines will have a 500 KVA DG set for emergency power supply to
cater to various lighting loads and the computer centre.
2.14.5 Fuel Requirement
Since most of the mine equipment are mobile equipment, they operate on Diesel
(High Speed Diesel). Diesel will be required for the following areas:



Mobile mining equipment;
As Fuel Oil for ANFO Explosive; and
Emergency diesel generating set.
It is estimated that the daily diesel consumption would be about 32-KL per day
(after expansion to 8.5-MTPA) for which a storage of 2X70 KL above ground steel
tanks have been envisaged.
2.14.6 Water Supply/Requirement
Industrial water is required for mining operations/establishment mainly for
sprinkling on haulage roads and at faces for suppression of dust. Water is also
required for vehicle washing and servicing utilities for equipment and also for
green cover development.
Total water requirement after expansion to 8.5-MTPA is estimated to be about
2000-m3/day. Water will be sourced from San river water at Kathkal site. The
break-up of water requirement for different units is given in Table-2.14.
TABLE-2.14
WATER REQUIREMENT FOR MINES
Purpose
Dust suppression / sprinkling on haul roads
Vehicle washing
Workshop
Domestic water
Green cover development
Miscellaneous & others
Total
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Existing (Before
After Expansion
Expansion) (3.0 MTPA)
(8.5 MTPA)
525
1500
75
200
10
20
30
50
50
150
30
80
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2.14.7 Employment Potential
The mining establishment presents opportunities of employment, to various posts
and under various cadre viz. management, supervisory, skilled workmen, semiskilled workmen and unskilled workmen besides casual workmen.
The requirement manpower has been evaluated keeping in view the high level of
mechanisation and productivity proposed for the mines on 3 shifts schedule of
working for all 365 days. In order to have 7 days/week working, suitable number
of relievers has been provided for the operating staff. The total manpower
requirement (after expansion to 8.5-MTPA) is estimated at 290, of which 42 are
executives and 248 non-executives.
2.15
Lighting and Communication
2.15.1 Mine Lighting
The mine is proposed to work in 3 shifts. Depending on the nature of the working
area, either shiftable or permanent lighting arrangements will be required.
Lighting arrangements are proposed to be provided in the following areas:





Active mining fronts - shiftable type;
Dumping/backfill areas - shiftable type;
Haul road/access roads-permanent type;
Central Trench/Conveyor Route- shiftable or permanent lighting; and
Semi-Mobile Crusher Site - shiftable or permanent lighting.
Permanent illumination will be setup along the mine access roads, truck haul
road, crusher, workshops, conveyor route and other permanent infrastructure.
2.15.2 Communication
It is proposed to have a modern communication network at the mine-complex.
The mines will be connected to the alumina refinery by a hotline telephone link.
Other communication facilities may include:


2.16
Wireless communication within mines; and
Satellite link communication.
Sources of Pollution
Virtually, all surface mining methods for any ore/mineral produce some
irreversible impacts. These produce dramatic changes in the landscape due to
large scale excavation. The environmental pollution due to the open cast mining,
in general, could be broadly classified into the following categories:





Air pollution;
Despoliation of land;
Solid waste/overburden;
Water pollution (resources and quality); and
Noise pollution and ground vibrations.
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2.16.1 Air Pollution
Mining operations contribute towards air pollution in two ways: addition of
gaseous pollutants to the atmosphere and the dust particles. The gaseous
pollutants include NOx, SO2 and Hydrocarbons. The sources of pollutants from the
existing mining activity include:




Operation of Heavy Earth Moving Machinery (HEMM) which mostly run on
diesel;
Loading /unloading operations;
Transportation of ore/overburden in dumpers; and
Drilling, blasting and crushing operations.
The above points can be classified as follows:

Point Source/Single Source
These are stationary sources, which emit air pollutants into the atmosphere from
a certain fixed point. In the proposed mine, the following sources or activities
form the point sources, which emit large quantities of Suspended Particulate
Matter (SPM).
Drilling
Drilling is an important activity of mining process. It will be carried out by using
Rotary blast hole drill and Jack hammers. Power drilling will be carried out with
the help of compressors. This operation is one of point sources.
Loading and Unloading
This is another important activity in the mining operations. Loading of ore, raw
materials etc, takes place through diesel driven hydraulic shovel /back-hoe.
Dumpers and belt conveyors will be used for the unloading of ore, overburden
etc.
Crushing
After the bauxite is taken out, it is subjected to crushing. This is the first step
towards ore processing. This activity will be carried out in the Semi Mobile
Crushing Plant unit by apron feeder. The above activities contribute to air
pollution in the form of SPM.

Line Sources
These are normally mobile sources, which emit atmospheric pollutants in the area
through which they pass. The following are the sources of air pollution falling
under this category.
Transportation
Bauxite raised from the mine will be transported to the semi mobile crusher
house using dumpers and transportation from crusher to alumina refinery will be
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done through conveyor loading station. Transportation also includes movement of
other vehicles in the mine lease area. The traffic on the haul roads is likely to
contribute towards dust concentration in the area. However, this is more of a
localized phenomenon. However, due to increased production, there will not be
any addition to dust concentration in a significant manner.
Dozing
This activity is carried out with help of the dozers. This is other type of line
source.

Area Sources/Multiple Sources
These constitute pollution from various sources and activities situated in the mine
lease area:
Overall Mining
The total mine area with all its mining activities constitute the area source. These
include all the mining operation activities and equipment, which contribute to
atmospheric pollution from the various units/activities.

Instantaneous Sources
The instantaneous sources consist of air pollution due to sudden/instantaneous
activities like blasting in the mine area.
Blasting
Blasting process involves slackening of big blocks of rocks/ore from the mines.
This operation generates dust, which results in the increase of SPM concentration.
It also contributes to emissions of certain gases (Oxides of Nitrogen and
Ammonia) due to the use of explosives like ANFO and slurry explosives.
The size of the dust particles emitted into the atmosphere plays a major role in
deciding the distance to which they may be transported. Particles of larger size
fall fairly rapidly and closer to their source, because of gravitational settling.
However, the aerosols because of their small size may be held in suspension for
years in the atmosphere and may be transported to buffer zone. Eventually,
these smaller particles are collected in raindrops and fall on earth. The
composition of these particles largely depends on the composition of the ore
being processed.
However, adequate dust suppression measures like sprinkling of water, plantation
on/along the haul roads will be carried out in the mine lease. Plantation has been
proved as the effective sink for air pollutants as trees are known to absorb
gaseous pollutants and arrest particulate matter. Moreover, trees also act as
filters for air borne particles because of their large size, high surface to volume
ratio of foliage and rough surfaces of leaf and barks.
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In addition, the proposed air pollution control measures (as given in Chapter-5)
will contain the air pollution to a major extent during the operation of the mine.
2.16.2 Water Pollution
The proposed Bauxite mine is located at hilltop. Mining is proposed to be carried
out upto a maximum depth of about 20 to 30-m from surface level and ground
water table (150-m below plateau top) in the area is much below the ultimate
mining level. The average height of the hill from the surrounding valley is about
200-m. Therefore, ground water table is not likely to be disturbed during mining.
Thus, there will not be any disturbance to groundwater resources due to the
proposed mining.
The wastewater generated from mines will be 200-m3/day. It is proposed to treat
the wastewater in septic tanks and utilize for greenbelt development.
The plateau top has no streams or nallahs, except the run-off of rainwater during
monsoon. All the surface water bodies are found only in valleys and plains. Those
streams are tributaries of river Indravati flowing on the western side of the
deposit about 7.5-km away. Even though, the plateau top has no streams, the
rainwater emerging from the top joins the streams of valleys and plains, erosion
from the top may cause siltation of these streams. Sufficient measures as
described in Chapter-5 will be taken to avoid erosion from the hilltop.

Affect of Mine Dewatering, if any
Groundwater is not encountered upto ultimate mine depth on plateau top. Hence,
groundwater does not intrude into mine working. There can be only one source
of water in mines, viz. rainwater. Rain water will be diverted from entering into
mines through garland drains constructed ahead of mining faces. Thus, water in
unpolluted state joins the natural slopes and streams. Direct precipitation of rain
into mines water is very limited. However, the rainwater directly precipitated into
mines will be channelised away from mine workings into sumps located
intermittently. The water collected in sumps (in the mined out area) helps in
recharging groundwater as most of it will percolate down the strata. The water in
sumps can also be used to water the plants in backfilled area.
Due to the above measures and the peripheral barrier, water from mines will not
pollute the streams or springs in valleys.
2.16.3 Land Despoliation
Large scale excavations are the basic causes of land despoliation. In all the
surface mining methods, first the overburden has to be excavated in order to
reach the ore body. Substantially, bauxite will be mined. Generally, overburden
removed is much less when compared to the volume of the Bauxite ore
excavated.
Quantity of solid waste likely to be removed during first five years will be about 7
Mm3 (11.41 MT). However, initially, the waste will be disposed on the plateau top
at a distance of about 1.0-km from active mining area. Suitably and adequate
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Chapter-2
Proposed Mining and Sources of Pollution
land reclamation measures will be implemented. The overburden dumps will be
protected by using parapet walls around the dumps. Garland drains also will be
constructed to mitigate the damage due to land despoliation.
2.16.4 Disposal of Solid Waste

Nature of Waste
The solid waste likely to be generated from the mining project will be in the form
of topsoil and waste rock comprising of soil, laterite, clay, lateritised Khondalite,
and Khondalite. The overburden thus collected in dump yard during the initial
mining period will be disposed in the mined out pits as backfill from the beginning
of the fourth year. The surface area required to dump the overburden at different
stages of mining is estimated based on swell factor of 20% and a dump height of
10-m. The solid waste generation details are given in Table-2.8 above.

Method of Dumping
Loosened rock mass obtained from blasting or ripping will be dozed, excavated
and loaded into rear dumpers. The slopes of external dumps will be maintained at
a maximum of 280. There will be two dumps and the total dumping area will be
about 50-ha.

Environmental Precautionary Measures
During rain, there is a possibility of washing off of loose materials along the
plateau slopes. Therefore, following precautionary measures will be undertaken
for controlling the wash off.

Around the dump slope, terraces are proposed;

Check dams are proposed along the
by boulders. During rain, water
off/sediments are arrested. Settled
and check dam will be cleared up by

Shrubs are proposed to be planted along the terraces to prevent erosion; and

Top of the dump will be properly levelled and compacted to prevent seepage
of direct precipitated water.
lower contours, which will be constructed
passes through the dams and washsediments, in between the waste dump
the help of dozer or back-hoe;
2.16.5 Noise Pollution
With the introduction of the sophisticated machinery into the mining operations
noise problem has become an issue. It has been established that noise interferes
with speech communication, causes annoyance and distraction.
The proposed mining activity envisages using heavy earth moving equipment.
The anticipated noise generating equipment along with the noise levels is given in
Table-2.15.
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Chapter-2
Proposed Mining and Sources of Pollution
TABLE-2.15
NOISE GENERATING SOURCES
Sr. No.
Mining Unit Operation
1
2
3
Exploration
Top-Soil (OB) Scraping
Sub Soil (OB) and Bauxite Ore
Loosening
4
5
Excavation and Loading
Transporting
6
7
Size Reduction
Water Sprinkling System
Source of Noise
Core Drill
Dozer Operation
Ripper Operation
Blast Hole Drillers
Blasting
Shovels Operation
Dumper Movement
Conveyors Movement
Explosive Van
Service Vehicle
Crushing
Trucks
Expected Noise
Level dB(A)
95
98
90
95
90
95
90
85
75-110
75-110
110
75-110
2.16.6 Vibrations
Mining activity also generates ground vibrations during the blasting. Ground
vibration, fly rock, air blast, noise, dust and fumes are the deleterious effects of
blasting on environment. The explosive energy sets up a seismic wave in the
ground, which can cause significant damage to structures and disturbance to
human occupants. It causes major damages to the pit configuration too.
By adopting controlled blasting, the above said problems were greatly minimized
at other existing mines. The impact is also minimized by choosing proper
detonating system and optimizing total charge and charge/delay.
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