ABSTRACT
Production
from underground mines in India has been declining since eighties. The decline
has been consistent from the level of 77.10 Mt in 1981-21 to 34.31 Mt in
2023-24, while the percentage share of UG production has reduced from 75% in
1971-72 to 3.44% in 2023-24. All stakeholders feel concerned about this decline
and there is a need to reverse this trend and boost underground production. The
inventory of Indian coal resource also suggests that the share of UG production
needs to be increased for sustainability of domestic coal production in future.
Various underground mining technologies have been tried in Indian mines in the
past, but these have not yielded desired reduction in cost of production
compared to opencast mining and many of them have failed. As such, these could
not be replicated in other mines. Mass production technology with Continuous
Miner has taken late entry in Indian mines. Also, there is ample scope for
introduction of Highwall mining in many mines. Coal India Ltd. has prepared a
vision document for boosting underground production to around 100 Mt by 2027-28,
based on applicability of various modern suitable technologies in different
mines. Implementation of this vision with rigorous monitoring is the need of
time. This paper analyses various factors leading to decline in underground
production and suggests the way forward for reversal of this trend.
1.
Underground coal
mining in India – historical perspective
History of coal mining in India indicates that it was predominant by
underground mining till the year of Independence. Some opencast mines were opened
after formation of National Coal Development Corporation (NCDC) in the year
1956. Yet Underground Mining was the leader in coal production till the years
of nationalization of coal industry (1971-73). The underground coal production
in the FY 1973-74 was 58.37 Mt out of the total of 78.17 Mt, amounting to
nearly 75% (1, 1984).
With completion of nationalization of coal mines, the underground mine
production also grew up along with that of opencast mines and rose to the level
of 75.53 Mt out of the total of 138.28 Mt (1, 1984), reducing its share to
around 55%. Underground mine production started declining thereafter, while the
production from opencast mines grew fast. By FY 2004-05 the UG production
declined in quantity to 62.35 Mt (16.30% of the total) against the total of
382.61 Mt (2, 2014).
The declining trend continued year after year and in the next 19 years,
that is by 2023-24 the coal production from UG mines in India reduced to 34.331
Mt (3.44% of the total) against the total of 997.826 Mt (3, 2024). This
downfall in UG production is not only from CIL mines, the major producer of
coal but also from the SCCL mines, which had been so far considered as
substantial contributor to UG production. In the last two decades CIL’s UG
production has declined from 47.041 Mt to 26.021 Mt (44.7%) while SCCL’s UG
production has declined from 12.974 Mt to 5.931 Mt (54.3%) (2, 2014 & 3,
2024). The trend of Indian coal production since nationalization is shown in
Fig. 1 (constructed from data in 1,1984, 2,2014 and 3,2024).
It may be worth mentioning here that alarmed by the steep decline in UG
coal Production, Ministry Coal in 2007 asked Coal India to prepare a plan for
boosting underground coal production and set up a target for increasing it to
75 Mt per annum by 2011-12. A nice document was prepared which was also
monitored for some years, but unfortunately UG production in CIL further fell
to 38.39 Mt in 2011-12 from the level of 43.322 Mt in 2006-07.
All the foregoing indicates that despite best of promises from the coal
producers and the Government there exists a lack of thrust on the part of both
to even arrest the decline, what to talk of increasing the level. It is for
sure that the country could not have depended on UG production only for meeting
the requirement of coal for growing demand of energy. Advent of advances in
opencast mining came as a rescue for boosting production from opencast mines
and thereby meeting the country’s coal requirement. However, it is also equally
necessary to keep the underground mining alive and agile so that when opencast
mining becomes unviable due to increasing depth, alternative method of coal
production is also available in the country to replenish the shortfall.
There are valid reasons for decline in underground coal production. The
author, with his vast experience in coal sector, has tried to analyse the
reasons for the downfall and suggests some way forward to reverse the trend.
2.
UG coal production
should be given a priority for reversal - reserves and resources criteria
Total coal inventory of India is assessed at 389.421 Bt as on 1st
April 2024 (3, 2024). Depth-wise break-up of this resource is shown in Table-1.
Table-1
Depth-wise coal resource in India
(Resource in billion tonne)
|
Depth Range
|
Proved Reserve
|
Indicated Resource
|
Inferred Resource
|
Total
|
|
0-300m
|
140.921
|
57.845
|
7.512
|
206.277
|
|
300-600m
|
46.557
|
67.222
|
13.855
|
127.635
|
|
600-1200m
|
9.500
|
23.495
|
7.101
|
40.096
|
|
0-600m
|
15.229
|
0.154
|
0.029
|
15.413
|
|
Total
|
212.207
|
148.716
|
28.497
|
389.421
|
Considering about 50% of the resource in the depth range of 0-600m to be
available in 0-300m, the total resource in the depth range of 0-300m works out
to 213.983 Bt, accounting to 55% of the total. This means that 45% of the total
resource lies in the depths exceeding 300m, which is currently considered as
the maximum depth limit for economic and technically feasible opencast mining.
Further, all the resources within 300m depth of occurrence are not mineable by
opencast due to their availability in low thickness seam with high strip
ratios. Also, the resources shown in the depth range of 0-300m have been
extensively mined out over the years, which are not accounted for in the
resource estimates. All these facts indicate that the resources that cannot be
mined by opencast may be much more than the estimates above.
Current high production rate from OC mining and huge imbalance in
production from the two technologies are likely to lead to fast depletion of
mineable resource by OC method and the production from OC mining may start
declining not in far future. If, thrust on underground mines and increasing
production from underground mines is not put as a policy decision, the country
may land in a situation when it will not be able to meet the requirement of
coal and dependence on import may further increase.
Loss of expertise for underground mining is another concern for the
country. Underground mining requires special skills for establishing access to
the deposit, variety of technologies depending on geo-mining conditions for
development and extraction of coal, special skills for supervision and
maintenance of safety. Such expertise take time to develop and without a
special thrust, it cannot be developed overnight. Declining UG production has
led to loss of focus on indigenous manufacturing of equipment for UG production
too. Hence, there is a need to pay urgent attention on reviving underground
mines and increasing production from underground mines.
3.
Major Reasons for
Decline in Underground Production
To analyse the reasons for decline in underground coal production it
would be necessary to examine the geo-technical characteristics of Indian
Coalfields, the cost consideration for mining, capability of the technology to yield
bulk production to meet the country’s fast-growing demand for coal and the
safety of work force. Underground mining in India has not been able to compete
with opencast technology on any of these scales and has been given a back sheet
by the coal producers. In many coal companies UG mining has been continued to
be practiced due to compulsions of retaining the workforce engaged in them.
Many of the old UG mines have been converted to opencast both from the
conservation aspect as well as for making mining economically viable.
3.1
Geo-technical
characteristics of Indian coalfields
In most of the coalfield seams occur in multiplicity and in close
juxtaposition. Some of the seams have multiple splits with partings varying
widely. There is wide variation in seam thickness within a small mine take
area. Some seams are very thick posing challenges for extraction. Some coal
bearing areas like, Noth Karanpura and Rajmahal coalfields in Jharkhand,
Talchir and Ib Valley coalfields in Orissa, Moher Basin (Singarauli) in UP and
Madhya Pradesh, Korba and Raigarh coalfields in Chhattisgarh have predominantly
thick to very thick seams and extensive opencast mining is being practiced
there. Other Coalfields like Jharia, Raniganj, Central India Coalfields (CIC)
of Chhattisgarh and MP, Wardha and other coalfields of western India and
Singareni coalfield of Telangana and the north eastern coalfields in Assam,
Arunachal Pradesh and Meghalaya have potentials for mix of technologies of
opencast and underground mining.
Most of the coal resource lie in thicknesses more than 4m. At places
they are banded and are traversed by sills, dykes and intercalations. Faults
with varying magnitude of throws and fold are very common in all coalfields.
Strata inclinations are generally less than 200 but, in some areas,
it varies from 180 to 500. In the north eastern coalfield,
it goes up to 800 (1, 1984).
Nearly all coals are prone to spontaneous heating. The incubation period
varies from 3 to 12 months requiring both fast extraction rate and small panels
for extraction. In the past many underground fires have been caused by
spontaneous heating leading to diversion of attention of the mine management
from production to dealing with fire.
The above geo-technical limitations restrict the potential of high
production underground mines and affect the economics adversely.
3.2
Cost
Consideration
With the advent of mass production technologies for opencast mining like
large capacity Shovels and Dumpers and Surface Miners the cost of production from
opencast mines far outweighs that from UG mines. As of now, the cost of
production of OC mines, even with a strip ratio of 10 m3/t or more
is less than that from UG mines for the same grade of coal and hence makes it
more acceptable to the producer on cost consideration.
3.3 Surface right availability
Availability of surface right for mining has been a major hindrance to
maintaining or increasing UG production. As such, seams have been developed on
Bord & pillar system and have been left as such, waterlogged due to
non-availability of land for depillaring. Around 5 Bt of coal reserves are
blocked in pillars today without proper conditions for their extraction. It was
opencast mining that enabled extraction of a part of such reserves in shallower
depths. However, the deeper developed reserves pose a great challenge today, as
these are in stressed physical conditions and waterlogged and have no or less
access available for their extraction.
3.4 Initial thrust on intermediate
technologies
Though, mechanisation in underground mines was introduced in a few
mines in pre-nationalisation days, like, introduction of cutter loaders, shaker
conveyors, chain conveyors, gathering arm loaders, Lee Norse Continuous Miner
and Continuous Miners with electric shuttle cars, the pace of introduction did
not receive the same priority after nationalization of mines. Coal India tried
to introduce Longwall mining in some mines but most of the underground mines
practiced Bord & Pillar method of development and partly depillaring with
Side Discharge Loaders (SDLs) and Load Haul Dumpers (LHDs). These are low
productivity machines and their operation for coal clearance, being a cyclic
activity, depended on manual drilling and blasting of coal faces. Manufacturing
of such loading machines started within the country and their application
became wide spread basically for eliminating manual loading of coal in to mine
tubs.
3.5 Inadequate infrastructure
for handling production potential from mechanisation
Most of the mines inherited from the pre-nationalisation days had
inadequate transport infrastructure to handle any increase in production from
mechanization. In fact in such mines the coal lifter by the SDLs or LHDs had to
be transferred in to tubs to be transported out by hope haulages. It was not
even sufficient to handle the full capacity of intermediate technology
equipment. Mass production technology required completely new construction of
matching transport system and surface coal handling system. This required more
investment and given the cost consideration compared to opencast mining; such
decisions always took a back sheet.
3.6 Withdrawal of stowing subsidy
for depillaring under built-up areas.
Coal Mine (Conservation & Development) Act 1974 was enacted to
collect some cess from the coal raised to provide some assistance to the coal
producers for some defined activities. One of the defined activities was to
give assistance for sand stowing for protective works. This encouraged the coal
producers to depillar coal under built-up areas. The practice continued till
2010 or so after which such assistance was stopped and later the Act itself was
repealed. This action reduced the production with stowing substantially as the
cost of stowing has grown very much with time.
3.7 Adverse safety record of underground
mines
Safety record of UG mines is worse compared to opencast mines. Though,
poor safety record of underground mines has not been a tool for reducing the
number of such mines, given a choice, one would prefer to reduce the number of
accident-prone mines. Poor economics, high safety risks due to waterlogged
workings and non-availability of sufficient reserves has led to closure of
several underground mines, particularly in BCCL and ECL.
4.
Technologies adopted
in the past in UG mining
India has tried and introduced many underground mining technologies over
the years. Bord & Pillar method of Development of coal seams and
depillaring has been most predominant. However, several attempts were made to
work coal seams with Longwall technology in many mines but this could meet
success in only a few mines as stated above.
Various technologies tried in different mines can be summarized as
follows:
Ø Bord & Pillar
o
Depillaring with caving
o
Multi section
depillaring with stowing – several mines with thick seam
o
Wide Stall extraction
of pillars with stowing – Bhagatdih, BCCL
o
Knife-edge method with
caving – Banki, SECL
o
Partial extraction with
leaving stooks – Searsole, ECL
o
Continuous Miner with
Shuttle Cars – Initially 3 mines; now at several mines.
Ø Longwall with individual prop support
o
Single lift with caving
– Moonidih, BCCL
o
Multi lift caving with
artificial wire mesh roof – Giddi, NCDC
o Multi section with stowing – thick seams in several
mines
Ø Powered Support Longwall with caving Several mines at different
locations
Ø Powered Support Longwall with sub-level caving and integrated
caving in thick seam – East Katras, BCCL
Ø Special Methods in specific conditions
o Multi Slicing with Stowing in steep seams (350)
(Jankowice) – Sudamdih, BCCL; Chasnala mine of SAIL
o Room- Rise (Komora) method with stowing for very steep
seam (550) – Sudamdih, BCCL
o Horizontal Slicing (Kazimierz) in steep seam (300)
with stowing.
o Bhaska Method with caving (700)– Tipong,
NEC
o Drop shield method with caving (700) – Tipong,
NEC
Introduction of mass production technologies like, Continuous Miner with
Shuttle Cars and mechanized Roof Bolters started much later with mixed success.
First Continuous miner was introduced in Chirimiri mine of SECL followed by
Tandsi in WCL and Jhanjhra in ECL. Initial years saw mixed successes due to
poor roof conditions in Tandsi and high cost of the equipment set. With
introduction of Continuous Miner Technology, it was proved that given a
suitable seam gradient, strata conditions and matching out bye transport
system, this technology could boost the underground production. However, this
realization came much later when UG production level fell to all time low.
Though, individual prop support longwall technology had been practiced
in the NCDC’s Giddi and Banki- Surakachhar mines in the pre-nationalisation
days, that was the only technology available at that time for introduction in
Moonidih mine of BCCL. in early seventies.
Powered Support Longwall Technology was first introduced in Moonidih
mine of BCCL in 1978, whose application later extended to other mines in the
country, like Pathakhera in WCL, Curcha, Kumda, Balrampur & Rajendra mines in
SECL, Dhemo Main, Seetalpur, Jhanjhra & Kottadih mines in ECL, East Katras mine of BCCL and a
few mines in SCCL. The technology had to be aborted at most of the mines
except, Moonidih, Jhanjhra and GDK7 mine at SCCL, due to various geo-technical
issues. Hence, the thrust continued on low productivity SDL and LHD
technologies as per the seam gradient suitability.
5.
Present
Technological Status
The status of underground technology has remained same as earlier. The
method of work continues to be dominated by Bord & Pillar system. However,
there is a shift towards increased deployment of Continuous Miner machines in
Bord & Pillar system. CMs have largely replaced LHDs, wherever possible, as
the seam gradient condition for application of the two is similar. SDLs
continue to be used in steeper gradient seams, where deployment of CMs is not a
choice.
Longwall technology application has not increased at all, largely due to
the properties in existing mines, not amenable for its adoption. As on date
also there are three power supported Longwall faces being worked, one each in
Moonidih, Jhanjhra and GDK7 mines.
Highwall mining has found increased application in some mines and their
number is increasing. Though, Highwall Mining is not exactly an underground
mining technology, it is considered in UG mining in India, as it is under the
ground extraction of coal from surface.
As on 31st December 2024, the number of Continuous Miner
sets, Longwall sets and Highwall Miner sets in use in Coal India Mines is shown
in Table-2.
Table-2
Deployment of Continuous Miners, PSLW and Highwall
Miners in CIL Mines
(as on 31st December 2024)
|
Name of Company
|
No. Deployed
|
Production in FY 2024-25 (Mt)
|
Productivity range (Avg) (tonne/day)
|
|
Continuous Miner
|
|
ECL
|
12
|
4.599
|
439 – 1978
(1239)
|
|
CCL
|
1
|
0.564
|
1546 (1546)
|
|
WCL
|
3
|
0.616
|
885 (885)
|
|
SECL
|
18
|
7.556
|
420 – 2313
(1397)
|
|
CIL Total
|
34
|
13.335
|
1402
|
|
PSLW
|
|
BCCL
|
1
|
0.463
|
1269
|
|
ECL
|
1
|
0.048
|
539
|
|
CIL Total
|
2
|
0.512
|
1125
|
|
Highwall Miner
|
|
BCCL
|
1
|
0.534
|
1463
|
|
ECL
|
2
|
0.551
|
823-1250
|
|
SECL
|
2
|
0.055
|
1109
|
|
CIL Total
|
5
|
1.14
|
1218
|
There is an increasing trend of deployment of Continuous Miners in CIL
mines. Given a suitable working condition, this mass production technology can
produce as much as a longwall in India can produce or even more. This is
evident from the above Table.
6.
Technological options
available
Having tried various technological options for underground mining over
the years in different geological settings it is now established that
Intermediate technology cannot meet the increased demand of coal from
underground mines.
6.1 Powered Support Longwall
(PSLW)
Longwall technology is mostly not suitable for majority of existing
mines, as these have relatively smaller mining lease area and are largely
developed on Bord & Pillar system in upper seams. Further, large number of
faults in Indian coalfields prohibit application of PSLW, limiting the length
and width of panels to be extracted. In many situations the roof behaviour has
been unpredictable and quite a few powered supports have been lost due to roof
collapses.
6.2 Continuous Miner with
Shuttle Cars
Continuous Miner has succeeded in proving its applicability with mass
production in several situations. However, its sustenance requires the surface
area to be available for depillaring. Non-availability of surface rights for
caving has been a major issue for creation of pillared reserves, so far. To
make Continuous Miner technology sustainable in UG mining, it will be essential
to acquire surface rights for depillaring with caving so that faster extraction
of reserves in mass quantity can be adopted.
6.3 Paste-fill technology with
Continuous Miner
Paste fill technology is an emerging technology under built up areas.
Though, this technology has been practiced in metal mines in India too, its
application in sedimentary formation is yet to be tried in India. It is
believed that this technology is in use in coal mines too, but with high
investment. It will be necessary to try this technology in Indian coal mine to
establish its techno-economic feasibility.
6.4 Highwall Mining
Extraction of coal from the periphery of disused/uneconomic opencast
mines by Highwall mining technology has been practiced in USA and Australia in several
mines. The cost of this equipment, till its production started in India, was
very high. In the last 13-14 years, applicability of this technology has increased
quite a lot. Study of the existing status of OC mines indicate application of
Highwall mining at several sites. Hence, this technology will also have
increased potential boosting underground production volumes.
It is, therefore, suggested that coal producers should put thrust on
large scale application of Continuous Miner, Highwall Miner, Paste-fill
technology with Continuous Miner under built up areas and PSLW in
geo-technically suitable conditions in greenfield mines. Shortwall mining with
powered supports for depillaring pillars developed on Bord & Pillar has
also been a success in SECL in the past. This may also be adopted in suitable
areas.
7.
Coal India Ltd.
Plans for Boosting Underground Production
For boosting underground production, CIL has made a detailed document
named “The Underground Vision Plan of CIL, 2023”.
The Vision Plan envisaged boosting underground production to 100 MTPA by
2027-28 (4, 2023) by focusing largely on Continuous Miner and Highwall Miner. The
action plan envisages:
a.
Scaling up Highwall mines,
b.
Identifying reserves for Punch Longwall mining,
c.
Identifying mines for extraction through
Paste-Fill technology,
d.
Working through MDO mode,
e.
Identification and approval of large number of
CM/Short wall/Longwall mines,
f.
Planning high capacity UG mines,
g.
Conversion to CM or addition of CM in mines
currently using Intermediate technology,
h.
Efficiency enhancement of existing
mines/running mines, and
i.
Strengthening of UG wing at Subsidiary and
CMPDI.
7.1
Scheduled and actual deployment of equipment
The population of Continuous Miner and Highwall Miner sets to be
deployed in different mines is given in Table-3 (4, 2023).
Table-3
Summary of No. of Continuous Miner and Highwall Miners
Deployment program in CIL Mines
|
Equipment
Set
|
Status
|
2022-23 (Existing)
|
Population in Operation
|
|
2023-24
|
2024-25
|
2025-26
|
2026-27
|
2027-28
|
|
Continuous
Miner
|
Planned
|
21
|
33
|
55
|
87
|
120
|
142
|
|
Actual
|
21
|
29
|
34
|
|
|
|
|
Highwall
Miner
|
Planned
|
1
|
3
|
8
|
11
|
11
|
10
|
|
Actual
|
1
|
5
|
5
|
|
|
|
7.3 Envisaged production schedule
from different technologies
With the above strategies and the action plans made mine-wise, the
production plan envisaged vis-vis actual achieved in the last two years are
shown in Table-4 (4, 2023).
Table-4
Envisaged Production Plan vis-vis actual achieved from
UG mines of CIL
(Figures in Mt)
|
Sl. No.
|
Subsidiary
|
2021-22
|
2022-23
|
Progressive Capacity
|
|
(Act)
|
(Tgt)
|
2023-24
|
2024-25
|
2025-26
|
2026-27
|
2027-28
|
|
ECL
|
Planned
|
|
|
12.07
|
12.93
|
20.24
|
25.92
|
27.81
|
|
Actual
|
9.00
|
9.85
|
9.183
|
8.475
|
|
|
|
|
BCCL
|
Planned
|
|
|
1.50
|
4.29
|
7.53
|
10.08
|
12.48
|
|
Actual
|
0.810
|
1.000
|
0.766
|
1.139
|
|
|
|
|
CCL
|
Planned
|
|
|
1.59
|
4.33
|
6.03
|
7.53
|
7.53
|
|
Actual
|
0.760
|
0.870
|
0.781
|
0.706
|
|
|
|
|
WCL
|
Planned
|
|
|
4.32
|
6.38
|
8.94
|
11.99
|
15.41
|
|
Actual
|
3.040
|
3.600
|
2.871
|
2.776
|
|
|
|
|
SECL
|
Planned
|
|
|
14.53
|
20.44
|
26.66
|
31.41
|
32.45
|
|
Actual
|
11.530
|
13.000
|
11.964
|
11.868
|
|
|
|
|
MCL
|
Planned
|
|
|
0.44
|
0.44
|
0.94
|
1.44
|
1.44
|
|
Actual
|
0.500
|
0.440
|
0.456
|
0.479
|
|
|
|
|
CIL
|
Planned
|
|
|
34.45
|
48.81
|
70.34
|
88.87
|
99.62
|
|
Actual
|
25.626
|
25.487
|
26.021
|
25.442
|
|
|
|
Note – UG production of CIL
has remained almost at the same level in the last 4 years, despite increased
deployment of Continuous Miners and Highwall Miners largely because the
production from other technologies like SDLs and LHDs has reduced.
8.
Suggestions
for the Way Forward
8.1
Use
CM technology, Shortwall and Longwall at suitable locations.
Mass production
technologies, like, Continuous Miner and Longwall with powered supports should
be used extensively in suitable site conditions. Use of Intermediate Technology
in such conditions should be stopped at the earliest. Shortwall with powered
support is a proven technology for extraction of developed pillars in Bord
& Pillar mines. This should be practiced for faster extraction of pillars.
Intermediate technology with SDLs should be practiced in only such areas where
application of CM and PSLW is ruled out. SDL technology should be backed with
mechnised drilling, roof bolting and coal evacuation. SDL loading into mine
tubs should be eliminated.
Availability of
land is a pre-requisite for mass production technology. Land acquisition or
taking land on lease rent for uninterrupted mass production should be given
equal thrust for underground mining as well.
8.2
Extensive
R&D studies on strata control required for site specific technology.
Some of the mass
production technologies in the past have not given desired results of
production and productivity due to roof failures. Extensive R&D studies are
required before implementation of such technologies in a particular mine from
the point of consideration of strata control. Equipment for roof support should
have a matching capacity with the cutting capacity of the face machine.
8.3
Develop
technology for cost effective backfilling/stowing/Paste-fill method.
Most of the underground
mining reserves underlie built up areas or forests. In both the situations,
caving of strata overlying coal seams is not allowed to be done from the
considerations of subsidence and possibilities of outbreak of fire in caved
goaves. Such areas will necessarily require backfilling, either by sand/bottom
ash of power plants or by Paste fill method. It is desirable, therefore, to
develop indigenous cost-effective backfilling/stowing technology for its wider
application.
8.4
Plan
for large size UG mines.
Smaller size
underground mines, as is the situation today, do not provide flexibility of
movement of working faces. High-capacity underground mines overseas have very
large mining lease areas. Some of the high-capacity underground mines have ML
area as large as 100 km2. Compared to this the UG mine size in India
is very small. This, coupled with the extensive faulting restricts the size of
panels to be worked and eventually restricting production capacity of the mine.
For planning high-capacity mines the mine size should be at least 10 km2
or more to provide flexibility of operation.
8.5
Scientific
studies with numerical modelling must be done before planning for depillaring
underneath backfilled OC mines.
Many of the future
underground mines are to be planned underneath backfilled areas of opencast
mines where top seams have been worked out by OC and lower virgin seams are to
be worked by UG method. The OB dumps exert dead weight on the UG mine
galleries. Scientific studies with numerical modelling must be done before
planning for depillaring underneath backfilled OC mines.
8.6
Develop
skills for UG mining with proper training – expertise getting lost.
With gradual reduction
of UG mines the manpower having received appropriate training in UG mining have
either retired or have been diverted in OC mining. UG mining needs specialized
skills and managerial capabilities. It is, therefore, necessary to train and
retrain the required manpower in UG mining of proposed technologies. In the
past many executives had been given exposure to good UG mines of different
continents. Such trained persons had delivered well. The same practice should
be adopted at this also, when the country is looking for setting up high
capacity UG mines.
8.7
Faster
sinking of Shafts and drivage of Inclines is essential.
Deeper UG reserves
require access through shafts or inclines. Sinking of shafts and drivage of
inclines are specialized jobs for which special skills are required. In the
late seventies and early eighties a few new shafts were sunk in the coal sector
for which help of foreign experts were taken. The industry has lost such
expertise gained through such assistance. Domestic companies need to be set up
for taking up such jobs for faster shaft sinking and incline drivage. CIL and
SCCL, with their large experience of UG mining, should set up wings for UG mine
construction and provide expertise to the new UG coal mining player.
9.
Policy
Initiatives Required by Government of India
Production from
underground mines cannot pick up until the Government of India takes up some
policy initiatives. So far, it has been left up to the production companies,
which take the path of least cost production. While economically it may be
justifiable, for the long-term sustenance of domestic production matching with
the demand projection, it is essential now for the Government to come forward
and take some policy decisions to facilitate increased production from
underground mines. Some of the suggested policy initiatives are as follows:
9.1
Facilitate
domestic production of underground mining equipment.
With decline in
underground mine production, the manufacturing capacity of equipment for
underground mining has also gradually reduced in the country. Domestic UG coal producers,
today, have to depend on imports for procurement of equipment for UG mining,
which are both costlier as well as suffer for spares availability. Government
of India should direct one of its mining equipment manufacturing companies, say
BEML, to collaborate with overseas manufacturers and start producing all sorts
of equipment viz, transport, coal extraction, man riding, material transport,
vertical transport, main mechanical ventilator etc. for domestic UG mining.
9.2
Allocate
underground mines of size more than 10km2
The mine size allocated should be large enough for
selecting alternative mining areas in case of problems in one area. This is
more so required as Indian coalfields are infested with large scale faulting.
Internationally, high capacity UG mines are of very large areas, some as high
as 30-40km2. Though, this may not be possible in this country, as
the coalfields have multiple seams, it is suggested that the minimum size of
coal block allocated for UG mining should be 10km2.
9.3 Enter into bilateral Agreements with countries advanced in underground mining
In the period just
after nationalization of coal industry, several bilateral agreements were
interred into with various advanced countries in UG mining at that time, which
led to development of a few UG mines including the present day Jhanjhra and
Moonidih mines. Government policy of withdrawing bilateral agreement concept
and leaving it open to competitive participation has pushed UG mining towards
back door. As of today, advanced UG mining countries are China, Australia,
Poland, Czech Republic and USA only. Government of India should have mine
specific bilateral agreements with these countries for developing high capacity
domestic UG mines.
9.4
Restore
Coal Mine (Conservation & Development) Act 1974
Coal Mines
(Conservation and Development) Act 1974 was brought in to help improve
extraction of coal under built up areas apart from other activities for
development of coal belts. This had helped the coal producers in depillaring
under built up areas as subsidies were available for sand stowing. With the
abolition of this act depillaring with hydraulic sand stowing has become highly
uneconomic, compelling the coal mining companies to resort to only development
of coal seams under built up areas and leaving them at that stage. Such areas
become inaccessible later due to spalling of roof and sides and the reserves
get sterilized for ever for mining, unless extracted by OC mining. It is
therefore suggested that the above Act should be restored to facilitate complete
extraction of coal under built areas and forests and subsidies may be provided
to the coal producers. For this CCDA Cess, as levied earlier may be re-imposed.
9.5
Facilitate
creation of mine construction companies for mine development
Development of a new
underground mine requires a lot of construction works like shaft
sinking, incline drivage, in seam drift drivage etc. These are one time works
and require a lot of specialized skills. Some skills were developed in the past
with collaboration with advanced countries like Poland and Russia. These are
lost now as most of the trained people have retired. It is necessary for Coal
India particularly, to create a subsidiary for mine development which could
provide specialized services to the domestic mine developers for creating these
facilities. It may not be possible for individual mine owners to create such
facilities.
Government of India
should direct Coal India Ltd to create one such subsidiary and develop the
necessary expertise required with required equipment. The Business Development
Directorate of Coal India should be given this task to create such a company.
9.6
Create
R&D fund for increased research in underground mining technologies
Research and Development in underground mining
technology needs further push by infusion of more capital as well as
involvement of research organization. Research organisations like, CIMFR,
CPMDI, IITs and other institutions having research facilities in mining, should
be given specific funds and tasks to develop best high production mining
technologies for specific mines/areas. Government of India should create a
large pool of fund by levying R&D cess on coal production for this purpose.
9.7
Create
stricter norms for land & environmental degradation by opencast mines with
heavy taxation
In the present system
of approval of OC mines, the costs of land and environmental degradation are
not factored adequately. The present laws do not compel mine owners to return
the land restored to its original or near original topography. While the underground
mines do not disturb the land and environment to the extent OC mining does, it
must compete with OC mine production cost to be economically viable. To create
a level playing field for both the technologies, it should be made mandatory
for both the technologies to adhere to the same standards in land and
environmental restoration. This will most likely make UG mining a choice on
cost consideration.
9.8
Facilitate
development of cost-effective Paste-fill technology
Paste-fill technology is a recently developed
technology for mining under areas to be protected on surface without
subsidence. While this technology has been largely practiced in metal mines,
its application in coal mines has been limited to some mines in China. It is
learnt that China is doing it successfully in some mines but its cost is high.
The capital cost required for the specialised equipment for this technology is
very high. Adoption of this technology, if found economically viable, would
open large prospects of mining under built up and forest areas without causing
any subsidence.
Government of India should inter in to a bilateral
agreement with Government of China for taking up a pilot mine for this
technology with the condition of technology transfer. Coal India may be
directed to identify one such mine for the purpose to introduce this
technology.
10.
Conclusions
Gradual reduction in the number and production of underground mines has
compelled people and the government to make plans for its reversal. Major
reason for such decline has been the competitive cost of production of coal
from opencast mining and largescale development of equipment manufacturing
capacity domestically for OC mining. Some of the deeper OC mines have their own
problems of high strip ratio, cost, and slope stability. This has compelled us
to think of increasing production from UG mining. Though, UG mining cannot meet
the total requirement of coal despite the best efforts, it is imperative for
all stakeholders to reverse the declining trend and boost UG production. Mass
production technology must be adopted extensively with matching mechanization
in all sub-systems. Acquisition of surface rights for mining, creation of
domestic expertise in UG mining, manufacturing of UG mining equipment
indigenously etc. would be necessary for reversal of this trend. CIL has made a
vision plan for increasing UG production to the level of 100 MTPA by 2027-28.
However, in view of the experience, its implementation is a great challenge. It
needs to be implemented with strict monitoring at the highest levels.
It is also mandatory on the part of the Government of India to take some
policy initiatives to facilitate increased production form underground mines.
Some suggestions have been made in this paper.
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References:
1. Coal Mining in India – A CEMPDIL publication, 1984.
2. Coal Statistics 2013-14 – A Publication of Coal
Controller of India, 2014
3. Coal Statistics 2023-24 – A Publication of Coal
Controller of India, 2024
4. The Underground Vision Plan of CIL, 2023.
