Methane drainage in India. and it was my final year project. if you want more study material then ping me. Thank you!

1. Economic analysis of methane drainage from
underground coal mines in indian context
Under guidance of:
Dr D. P. Mishra
Associate Professor
Department of mining engineering
Submitted By:
Harish Kumar Machra-17JE003549
Navendu Kumar- 17JE003560

2. Outline of the presentation
➢ Objective of study
➢ Scope of the work
➢ Introduction and coal bed methane
➢ Literature Review
➢ Characteristics of methane gas
➢ Reservoir Properties
➢ Measurement of Gas content
➢ Coal Mine Methane in India
➢ Methane Drainage
➢ Pre-Drainage
➢ Post-Drainage
➢ Methane utilization
➢ Case Study 1- Moonidih Mine
➢ HYPOTHETICAL PROJECT
➢ Conclusion
➢ Way forward to our study
➢ References

3. OBJECTIVES OF THE STUDY
● To study and analysis of various methane drainage practice
● To Determine Direct and Indirect benefits drainage system
● To evaluate Economic feasibility of methane drainage in indian mines
● To find out various utilization option of methane gas

4. SCOPE OF PROJECT
This project is focussed on the following targets:
❏ Study of different methods which is viable for the Methane drainage in Indian mines
❏ Reservoir modelling and simulation studies for methane drainage
❏ Cost estimation-based analysis of methane drainage

5. INTRODUCTION
● Coal - Largest components of india’s energy sector(around 56% in 2017)
● 12% from underground mining
● Methane formed during coalification process and remain trapped in the
coal(absorbed and free gas)
● Ejected during excavation in mine environment
● Methane - Inflammable gas cause fire hazard (b/w concentration 5%-15%)
● Methane has global warming potential of 34
● Methane can be used as a fuel
● Methane fossil energy resources, methane is the cleanest source of energy

6. COAL BED METHANE
➔ First CBM project in 1980. Its new finding in mining as a new source of energy
➔ Methane content comes from three processes biogenic processes, thermogenic processes
and post formation stages
➔ It is coming and it remains adsorbed on coal surface
➔ Coal has got very large adsorption surface area
➔ In India methane basin is very small but our basin are very thick coal seam and we also got
multiple seams
➔ Thickness and depth of the coal seam plays very important role in CBM
➔ In CBM we go for hydraulic fracturing to have good permeability
➔ In normal CBM, we take out water means we are reducing the pressure and the gases
present in coal they dissolve and they come out with water and then we are taking out that
gases

7. Characteristics of Methane Gas
● Methane is an odourless, tasteless, colourless, inflammable, lighter-than-air gas
● It formed during coalification process and Methane is a major component (80% to 95%) of coal
gases
● it's low density causes it to concentrate in the higher parts of underground mine environment
● If ventilation is insufficient to properly mix the air with the mine air, methane levels between 5%
and 15% can form an explosive mixture
● which, if ignited, can have catastrophic consequences and further it can cause coal dust explosion
● Methane drainage is an effective technique to alleviate methane emission problems in coal mines
● For successful drainage, system must be design according to specific geologic conditions, such as
gassiness of the coal seam and overlying strata, specific gas emissions of the mine, and coal seam
thickness and continuity

8. Reservoir Properties
➢ Gas drainage practices should be designed based on mine-specific conditions
➢ Following reservoir properties should consider before installation of methane drainage
technique:
1. Gas content of coal seam and their gas isotherms;
2. Permeability;
3. Reservoir Pressure;
4. Diffusivity of coal;
5. Water content and quality of water;
6. Ground stresses and elastic properties of surrounding strata
➢ Coal porosity is generally low (1%–4%) and does not have a significant influence on gas
production

9. Measurement of Gas content
● The volume of gas contained in a ton of coal is termed gas content of the coal
● It is expressed in cubic meters per metric ton (m3/t)
● The volume of gas contained in coal is dependent on the rank, temperature, and pressure or
depth of the coal seam
● Gas content measurement methods are classified as(a) conventional and (b) pressurized
desorption techniques
● In conventional technique, coal cores or drill cuttings are retrieved from the core hole and
immediately put in a sealed container to measure the desorbed gas
● In conventional method uncertainty in the estimation of gas lost during sample retrieval and
handling
● In pressured core desorption technique, gas loss is minimized by sealing the coal sample down
the core hole

10. Direct measurement of coal gas content
Fig: Direct measurement of coal gas content

11. Direct measurement of coal gas content
➢ Coal cores or drill cuttings are deposited in a sealed vessel and desorbed gases are measured
periodically until the desorption rate is insignificant
➢ Total volume of gas thus produced is known as the desorbed gas
➢ The cumulative volume of desorbed gas plotted on the y-axis against the square root of time yields a
straight line, and its intercept on the y-axis is a measure of the gas lost from the core before it was
deposited in the sealed container
➢ Subsequently, a portion of the core is ground in a hermetically sealed mill to release the residual gas
➢ The sum of the three component volumes—desorbed gas, lost gas, and the residual gas—is the total gas
contained in the sample
➢ the total Gas reserve G = ᑭAhV
ᑭ is the density of coal t/m3
A is the area of deposit, m2
h is the mining height, m
V is the gas content, m3/t

12. Coal Mine Methane in India
● Most coal mines in India, are classified as Degree I or II gassy mines, indicating that they are moderately
gassy
● Some mines are extensive gassy and classified as Degree III
● India’s CMM emissions are estimated to be 2.6 trillion cubic meters (Tcm) (DGH, 2019)
● As of 2019, drainage of CMM in India is limited with no active commercial CMM recovery projects

13. Methane Emission in Longwall
● Methane emissions can adversely affect both the safety and the productivity of underground
coal mines
● During longwall mining, methane emissions can originate from three major sources:
1. gas emissions from the ribs surrounding the bleeder ventilation system
2. gas emissions from the active longwall face and mined coal on the conveyor belts
3. gas emissions from subsided strata
● The first gas source originates from the unmined coalbed adjacent to the development entries of
the bleeder system and from the solid coal ribs
● The second source is the combination of the gas content from the mined coal itself and the
methane being emitted from the fresh face on the longwall
● The third source is the fractured and caved rock in the subsided strata (gob)
● methane control solution, especially in high in-place gas content coalbeds, is drilling methane
drainage boreholes into the panel area prior to longwall mining

14. Methane Drainage
➢ Why?
Investment in good gas drainage practices results in less mine downtime due to
gassy mine conditions, safer mining environments, and the opportunity to
utilise more gas and reduce mine methane emissions
➢ Practical gas drainage problems at coal mines can generally be resolved by
applying existing knowledge and techniques and new technology only be
introduce if the existing technique failed to give satisfactory result
➢ Methane drainage system performance can be improved through proper
installation, maintenance, regular monitoring, and implementation of
systematic drilling plans

15. Pre-Drainage
● Pre-Drainage menas methane drainage is done prior to the the mining
● Pre -drainage is also sometimes necessary for reducing outburst risks
● Because the drainage is undertaken before mining, the collection systems are not likely to be
disturbed by ground movement, and, relatively high purities of gas can usually be extracted
● Drainage from blocks of coal ahead of mining produces consistent gas flows of high purity,
provided that the permeability and gas contents of the coal are sufficient to allow significant gas
flow
● Coal permeability directly affects the time required to sufficiently drain the coal seam
● The lower permeability coals require a greater number of boreholes needed to achieve the
desired methane levels
● Rotary drilling is commonly employed for drilling underground in seam holes of 100 m to 200 m
● Holes of 1,000 m or more can be installed using underground directional drilling techniques

16. Schematic of Pre-Mine Drainage
Fig: Schematic of Pre-Mine Drainage from Lateral Wells Drilled from the Surface

17. Post-Drainage
➢ Post-drainage simply means the methane drainage is done after the mining
➢ The low permeability of the coal seams (<0.1 mD) and geologic characteristics of the seams
(e.g., soft coals, faulting) are not conducive to predrainage techniques then the post
drainage technique is used
➢ In Post drainage method, methane is drained before it enter to the mine airways
➢ In this, mainly access to the caved zone (post mining zone) above or below the zone
➢ Following three drilling pattern used in post drainage:
1. Guided horizontal boreholes: Drilled from a roadway or specially prepared drilling
galleries.
2. Cross measure boreholes:One set is drilled in advance of the retreating longwall face into
the overlying roof rock behind the coalface
3. Surface goaf boreholes: Drilled from the surface into the upper limits of the goaf, usually in
advance of mining

18. Various Post-Drainage Drilling Methods
Fig: Various Post-Drainage Drilling Methods

19. Methane Utilisation
Potential utilisation of CMM in the range of 30% to 100% methane in the following
manner:
1. In Power Generation: Gas engine generator can use at mine site or export to the grid
2. High quality Pipeline gas
3. Use as fuel: in steel furnaces, kilns, and boilers
4. Feedstock to the fertilizer industry
5. As vehicle fuel (LNG or CNG)
6. At Mine site: in Heating, Cooking, Boilers, Coal fines drying, Miner’s residences

20. Case Study 1- Moonidih Mine
● Moonidih is the first ever mine in which Powered Support Longwall (PSLW) technology adopted in india
● The Moonidih mine is deep, strongly gaseous (Deg. III) with high strata temperatures and rare incidents with
hot strata water
● So it create a favorable condition for adoption of methane drainage
● The CBM Project approved by govt in 1999. Earlier 3 wells were drilled up to 1059 m depth.
● And CBM is utilize in electricity generation by gas based generator
● So far more that 1.10 million units of electricity has been generated
● A total of 7970.47 million cubic metres of Gas-in-Place potential has been estimated within the known
Moonidih CBM block
● Area of the moonidih CBM project is around 20.63 km2
So, In this case study we studies about the location and geologic condition of moonidih, total CBM reserve
Seam vise, approach toward drainage of methane, analyse the current situation, wells location and production
of gas from the well, gas utilization condition, direct and indirect benefits, and economic analysis of the project.

21. Surface plan of Moonidih Mine
The detailed plan of moonidih along with the moonidih
CBM Project.(in left)
In moonidih there is 18 identifiable seams and thickness
vary from vary thin to vary thick. All seams are degree 3.
And gas content increase with the depth.
Upper 3 seam are worked out. So the CBM project from
Seams XV and below up to Seam-II in an area of about 13
sq.km, have been considered as target seams for CBM
development.
The maximum depth of the bottommost Seam-II is
projected at about 1225m. And cumulative thickness of
seams(XV and below) about 80m.

22. General Method of Production
Details planning
for coring and
non-coring,
design the
drilling string,
and logging at
each stage.
Drilling and
casing of well
Hydro
-Fracturing
Dewatering Production
For increasing
productivity
by injecting
fluid at high
pressure, more
permeable
zone
Removing
water from
coal seam, to
decrease
natural
pressure and
increase gas
flow
Gas and water
separated at
surface, CBM
collected from
no of wells

23. Output and Benefits
➔ Installed two 250 Kw gas based generator
➔ 187299 Kw electricity generated during year 2012-13 from three wells
➔ estimated annual emission reductions to be1.109 MMTCO2E
➔ Five CBM wells were proposed at Moonidih under the Demonstration Project out of which
three wells were drilled with estimated production capacity of 5000 m3/day/well
➔ Some are Following direct and indirect benefits:
● CBM provides a clean source of energy
● The CBM, a highly potent GH gas, if emitted in environment via ventilation air causes global
warming
● Provide safer mining environment for working
● Reduce ventilation cost
● Generate electricity
● Adoption of new technology boost confidence

24. Hypothetical Project for Economical analysis
➢ CBM Project - Captive intensive, time intensive
➢ Proper spacing, designing and optimum number of drills should be economically viable
➢ Area of project- 100 km2 (assume)
➢ Operating efficiency - 90%(assume)
➢ Total number of wells - 155
➢ CAPEX - (escalated @6% p.a.) includes cost of surface facilities, administrative cost, land
acquisition and other costs
➢ OPEX - (escalated @8% p.a.) includes electric power and fuel for wells and GCS(gas
collecting system) work over jobs, manpower, project, establishment and overheads
➢ Calculation of well cost has been done on the basis of cost as per present day cost of
drilling, completion and fracturing as per procedure and technology
➢ Gas Price = $ 5.1/MMBTU(Metric Million British Thermal Unit)

25. Estimated Cost of various installation and land
Table: Above table contain various approximate cost of various activity, installation(These are taken from various sources)
Sl No Various Surface Facility, land and administrative functions Cost(Rs, Crore)
a Flow lines for Gas and Water 30.62
b Plant, machinery and land for gas collecting system 32.88
c Dehydrator at surface, Compressor for concentration and other associated
units
27.50
d Consultancy for project, other engineering service 15.00
e Administrative, land acquisition(100 km2) and project supervision 106.00
Grand Total 220.50(approx)

26. Estimation of capital investment
Above table contain costs like drilling, gcs water management, administrative.these are assumed and taken from the various CBM Project
Year Wells costs Other costs Total
No of drilled
wells
Total well costs in that
year
GCS water handling
cost
Administrative
cost
Overall CAPEX Escalated cost
@6%
1 9 1 1 1
2 26 138.5 19 19.25 176.75 187.36
3 37 220.5 20 29.5 270 303.38
4 39 214.5 20 29.25 263.75 314.14
5 17 85.5 19.5 13.25 118.25 149.29
6 8 46 19 8 73 97.7
7 10 51 8.75 59.75 84.76
8 9 49.1 8.5 58 87.22
Total 155 805.5 97.5 117.5 1020.5 1224.85

27. Overall financial details
We calculated CAPEX and OPEX for the entire life of project in which we considered every type of cost(Power cost, manpower,
Supervisiotion) Fuel cost. And we observed that:
● Profit in First 4-5 years is negative that means
high investment required at the starting of project
● After 5 year the Profit is tend to positive and
remain positive to the end of the project
● It clearly shows the economically viability
● This profit is direct we can see but there are
various indirect benefits that we discussed earlier

28. Conclusion
From the project and case studies we concluded:
★ India has huge capacity in term of resources, development, production, market of the CBM
★ Success of any CBM Project highly depend on which type (method) we adopt and these methods
are very vulnerable to the geology, permeability, gas content etc.
★ And, CBM Projects are time intensive and financial intensive. So It require long term study,
planning and proper feasibility study(if possible feasibility study may done by two agency
separately and then compare the final result)
★ In CBM the planning of drilling is very very critical. Various simulation modelling should be done
to determine the best location, spacing between the drilling, gas collection centre etc.
★ For CBM Production new technology is require so it require a lot from funding. In this govt or any
other international organisation(USEPA) can provide fund as well as incentive
★ Some challenges india is facing in CBM Project are Regulatory issues, legal issue, land
acquisition and socio-political issues

29. Way Forward to our study
In this Project we studies the CBM in India in generalized form and we did three case studies. In
which one was hypothetical because of not access to the field and lab. Here are some of our
ideas to continue our study:
● Topic specific study like Simulation modelling for Methane drainage, Designing of drilling
system in a particular method, How to increase methane production using CO2 flooding
and coal gasification
● We will study various other CBM project that is going on at various stage in india by RIL,
ONGC, CIL, Easser by field visiting
● We will try to gather more inputs for our study through lab work, studying new journals on
the topic
● Finally, Our aim to write a paper on our study and try to publish that paper

30. REFERENCES
Some of references from these we took help for our study:
➔ “Numerical analysis of the influence of in-seam horizontal methane drainage boreholes on longwall
face emission rates”, C.Ö. Karacan, W.P. Diamond, S.J. Schatzel
➔ “Forecasting Methane Emissions from Hard CoalMines Including the Methane Drainage Process”,
Magdalena Tutak, and Jarosław Brodny
➔ “Handbook for Methane Control in Mining”, Fred N. Kissell
➔ “Best Practice Guidance for Effective Methane Drainage and Use in Coal Mines”, Economic Commission
for Europe
➔ SME MINING ENGINEER HANDBOOK
➔ “Feasibility report on Moonidih Coal Bed Methane project”, BCCL
➔ “Pre-Feasibility Study for Methane Drainage and Utilization at the Pootkee Colliery, Damodar Valley”,
USEPA
➔ “Coalbed Methane in India- Opportunities, Issues and Challenges for Recovery and Utilization”, Ajay
Kumar Singh and Partha Narayan Hajra
➔ “Economic modelling for coal bed methane production and electricity generation from deep virgin coal
seams”, A.A. Jaya V. Sarhosis, H.R. Thomas
➔ “Fugitive methane emissions from Indian coal mining and handling activities: estimates, mitigation and
opportunities for its utilization to generate clean energy”, Ajay K. Singh, Jaywardhan Kumar