Surface Mine Methane Emissions and Project Opportunities

Coal Mongolia 2012Second International Coal Investors Conference 

and ExhibitionFebruary 9‐10, 2012

Raymond C. Pilcher, James S. Marshall & Charlee Boger

Select Country SMM Emissions

GMI (2010): Coal Mine Methane Country Profiles. Global Methane Initiative. December, 2010. http://globalmethane.org/tools-resources/coal_overview.aspx; IPCC (2006): 2006 IPCC Guidelines for National Greenhouse Gas Inventories. Volume 2: Energy, Chapter 4:Fugitive Emissions. http://www.ipcc-nggip.iges.or.jp/public/2006gl/pdf/2_Volume2/V2_4_Ch4_Fugitive_Emissions.pdf; UNFCCC CommonReporting Format, August 21, 2011; USEPA (2011): Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2009. USEPA #430-R-11-005. April, 2011. http://www.epa.gov/climatechange/emissions/usinventoryreport.html

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Country

Estimated Surface Mine Methane 

Emissions (Million cubic meters)

% of Total CMM Emissions Year Source

Russia 1,056 33% 2009 UNFCCC CRFKazakhstan 450 47% 2009 GMI (2010)United States 903 18% 2009 USEPA (2011)Indonesia 34 100% 2005 GMI (2010)Mongolia 3.7 100% 2008 GMI (2010)Colombia 254 90% 2010 GMI (2010)

Philippines 0.22 92% 2008 GMI (2010), IPCC (2006)

India 43 2% 2008 GMI (2010), IPCC (2006)

Viet Nam 3.2 6% 1994 GMI (2010)

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Initiatives for Surface Mine Methane Drainage

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Initiatives for Surface Mine Methane (SMM) Drainage

2003: U.S. Bureau of Land Management (U.S.BLM)– Conflict Administration Zones (CAZs)

2005: EPA Surface Mine Methane Assessment (internal report)

2009: U.S. Verified Carbon Standard (VCS)  methodology

2010: Clean Development Mechanism (CDM) methodology– ACM0008 version 7 now includes opencast/surface mines

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U.S. Surface Mine showing CAZ5

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Accommodating the Variability in Surface Mine Design

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Variability in Surface Mine Design Challenges to Pre‐Mine Drainage

• Strip Mine–Mine develops along strike of the coal seam

–Mine can be developed in tiers or contours parallel to strike

–As each strip is mined, the waste rock is placed in the excavation produced by the previous strip.

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Strip Mine

Strip mine near Palangka Raya, Central Kalimantan, Indonesia. http://www.kalimantancoal.com/2011/01/coal-indonesia/

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Variability in Surface Mine Design Challenges to Pre‐Mine Drainage

• Open‐Pit Mine– Numerous levels or benches (stepped from surface to bottom of pit

– Pit walls designed  for slope stability and  prevention of rock falls or wall failure

– Haulage road located along side of pit to remove coal and waste rock

– Waste rock is piled at surface near edge of pit

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Open‐Pit MinePanian Mine, Semirara Island, Philippines

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Approaches to Drainage

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Vertical in Advance of Mining

–Boreholes are shut‐in as mining approaches/evidence of air in produced gas

– Surface equipment and casing is removed prior to mine‐through

– Timing – producing as far in advance of mining as possible

–Applicable to strip mines

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Lateral in Advance of Mining

–Depending on placement, boreholes may continue to produce during mining and post mining

–Applicable to some single seam strip mines and to open pit mines

–May access more coal if sidetracks are employed

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Laterally‐drilled Borehole15

Surface Mine Drainage Considerations

• Coordination of gas drainage project development with mining operations is essential

• Surface logistics–Waste piles, storage, space issues–Gas transportation

• Permanent vs. temporary gathering lines

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Qualifying Surface Mine Methane Production

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Qualifying Production Under VCS

NARM PDD: https://vcsprojectdatabase1.apx.com/mymodule/ProjectDoc/Project_ViewFile.asp?FileID=70&IDKEY=niquwesdfmnk0iei23nnm435oiojnc909dsflk9809adlkmlkf496530

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Qualifying Production Under CDM

ACM0008: http://cdm.unfccc.int/methodologies/DB/OA37XAW7EI9WHJVZ97RGH2EZ5S9E93/view.html

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Understanding the Zone of Disturbance

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The Zone of Disturbance• Drilling into the Zone of Disturbance using a laterally 

drilled borehole• According to ACM0008, the zone of disturbance is 

“typically 140 m above and 40 m below the targeted coal seam”

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The Zone of Disturbance

• Current Interpretation

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Overburden Removal Increases Permeability

• Permeability increases exponentially with decreasing effective stress

• Effective stress is diminished as overburden is removed during mining

• Permeable pathways occurring in geologic structures such as breached folds or faults are enhanced as overburden is removed.

• Matrix and fracture permeability is enhanced as a function of the stiffness of the rock mass, density of fracturing and thickness of overburden removed.

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Impact of Rock Stiffness on Increases in Permeability as Overburden is Removed 

Medium‐Volatile Bituminous Coal Sub‐bituminous Coal

Fracture compressibility for bituminous coal from A New Coal‐Permeability Model: Internal Swelling Stress and Fracture‐Matrix Interaction by Hui‐Hai Liu and JonnyRutqvist, Transp Porous Med (2020) 82: 157‐171.Fracture compressibility for sub‐bitumious coal , high volatile bituminous and equation for relationship between overburden removal and permeability increase fromImprovements in Measuring Sorption‐Induced Strain and Permeability in Coal by E.P. Robertson, SPE 116259, 2008 SPE Eastern Regional/AAPG Eastern Section JointMeeting held in Pittsburgh, Pennsylvania.

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Opportunities for Emissions Reductions at Surface Mines in Mongolia

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Comparison of CBM Producing Basins in USA to Coal Basins in Mongolia

San Juan

Raton

Powder

River

Tavan-tolgoi

Nariin-

sukhait

Nuurstk-

hotgor

Coal Rank hvBb- mvb

hvBb- mvb

subB hvBb-mvB

hvBb hvBb-c

Gas Content m3/tonne

3-14 6-14 <3 ? ? ?

Max. Coal Thk. 8-14m <3.5m 30-50m 1-73m 1-54m 1-38m

Cum. Coal Thk. 13-20m 13-22m 75-105m ? ? ?

Sorption Time >52 days >8 days >7 days ? ? ?

Depth of Completion ~800m ~650m ~150m ? ? ?

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Model for Methane Generation in Upper Texas Gulf Coast

D D'

Datum Sealevel - 3000

188°

EcBEsbEh

Shell#1 Kyle Est.45-29E-8

UPRCBarracuda #1

300° @ approximately 10,700 ft.

Base of Wilcox

190°

Top of Calvert Bluff

WeberSchmidt Unit #1

Top of Simsboro

Midway

Sealevel

BIOGENIC THERMOGENICBIOGENIC ENRICHMENTTHERMOGENIC WITH

STUDY AREA

Lower Coal Bearing Interval

(B Sequence)

Upper Coal Bearing Interval

(D Sequence)11,752' T.D.

10,332' T.D.

0 FT

2,000 FT

4,000 FT

6,000 FT

8,000 FT

10,000 FT

12,000 FT

Ground Water Recharge

Values 20-60 ohmsValues 10-20 ohms

Values greater than 60 ohmsEXPLANATION

190° = Equilibrium Temperature °F

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Dry gas with isotopically light methaneGas composition controlled by (1) mixing of biogenic methane and/or (2) oxidation of heavy gasesLocated in margins and shallow central parts of basins.

Zone of Original Gas

Wetter gas with isotopically heavier methaneGas composition controlled by rank and composition

Located in deep and central parts of basins

Few 100'sto 1000'sof feet

COAL

After Rice, 1993

of associated coal

Zone ofAlteration

Zone ofOriginal Gas

Model of Methane Occurrence and Enrichment in Coal

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Hypothetical Resource Estimate for Mongolia Coal Deposit

Cross‐section through part of Ovoot Tolgoi hvB‐hvA Coal Deposit

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Thickness of Seams Occurring in Ovoot Tolgoi Deposit

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In‐ Place Coal Resources Delineated by 430 Boreholes Drilled from 2006 through 2009

Resources estimated using cross‐section method

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Hypothetical Isotherm for hvB‐hvA Coal Rank

0,0 1,0 2,0 3,0 4,0 5,0 6,0 7,0

0,0

1,0

2,0

3,0

4,0

5,0

6,0

7,0

8,0

0

50

100

150

200

250

0 100 200 300 400 500 600 700

Pressure (Mpa)

m3/t

scf/ton

Depth (m)

Range in SurfaceMining Depth

Possible Range in UndergroundMining Depth

For illustration purposes only!

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Hypothetical Gas Content Probability Distributions for Ovoot Tolgoi Coal Resources

For illustration purposes only!

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Hypothetical CMM Resources of Ovoot Tolgoi Coal Deposit 

Potential Surface Coal Mine  

CMM Resource Estimate (million cubic meters)

P90 P50 P10649 732 816

Potential  Underground Coal Mine  

CMM Resource Estimate (million cubic meters)

P90 P50 P10562 630 696

For illustration purposes only!

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The Petroleum Resources Management System37

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Examples of Emission Reductions at Surface Mines in Asia and the USA 

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Estimated Emission Reductions from Surface Mine Projects

ProjectAverage Annual Emission 

Reductions (tCO2e) Emission Reductions for Crediting Period (tCO2e)

Wahana Baratama, Indonesia 207,111 1,449,778

Semirara, Philippines 385,478 2,698,346North Antelope Rochelle, Wyoming, USA

90,463 904,628

Wahana Baratama Coalbed Methane Generation Project PDD: http://cdm.unfccc.int/Projects/Validation/DB/9Y4C1SLSOQIMHIZGRXF053RFNRQERO/view.html; Semirara Coalbed Methane Generation Project PDD: http://cdm.unfccc.int/Projects/Validation/DB/YCCWHT4J05P2A4OSN6LGDGK9RYEBXQ/view.html; NARM PDD:https://vcsprojectdatabase1.apx.com/mymodule/ProjectDoc/Project_ViewFile.asp?FileID=70&IDKEY=niquwesdfmnk0iei23nnm435oiojnc909dsflk9809adlkmlkf496530

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End‐Use Options

Pipeline SalesPower Generation

CNG/LNG Flaring

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Prospective Opportunities

Countries with Projects Countries with Project Opportunities

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Conclusions

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Conclusions

• Revision to ACM0008 and voluntary carbon market opportunities have put the spotlight on SMM

• Worldwide SMM market is untapped• SMM development considerations vary greatly

– Mining method– Location– End use market

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Thank You

For more information…

James S. Marshall: jmarshall@ravenridge.comRaymond C. Pilcher:  pilcher@ravenridge.com

Charlee Boger:  cboger@ravenridge.com

www.ravenridge.com

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