User’s Guide for Estimating Methane Emissions from Coal Mining and Abandoned Coal Mines Using the State Inventory Tool January 2022

User's Guide for Estimating
Methane Emissions from Coal
Mining and Abandoned Coal
mines Using the State
Inventory Tool

January 2022

Prepared by:
ICF

Prepared for:

State Energy and Environment Program,
U.S. Environmental Protection Agency

This section of the User's Guide provides instruction on using the Coal module of the State
Inventory Tool (SIT), and describes the methodology used for estimating greenhouse gas
emissions from coal mining and abandoned coal mines at the state level.

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Module 5 - Coal Module

January 2022

Table of Contents

1.1	Getting Started	2

1.2	Module Overview	3

1.2.1	Data Requirements	4

1.2.2	Tool Layout	5

1.3	Methodology	6

Step (1) Select a State	6

Step (2) Enter Emission Factors	6

Step (3) Complete Worksheet for ChU from Coal Mining	8

Step (4) Complete Worksheet for ChU from Abandoned Underground Coal Mines	10

Step (5) Review Summary Information	13

Step (6) Export Data 	14

1.4	Uncertainty	15

1.5	References	15

State Greenhouse Gas Inventory Tool User's Guide for the Coal Module	1.1

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Module 5 - Coal Module

January 2022

1.1 Getting Started

The Coal module was developed using Microsoft® Excel 2000. While the module will
operate with older versions of Excel, it functions best with Excel 2000 or later. Some of the
Excel basics are outlined in the sections below. Before you use the Coal module, make sure
your computer meets the system requirements. In order to install and run the Coal module,
you must have:

• IBM-PC compatible computer with the Windows 95 operating system or later;

• Microsoft® Excel 1997 or later, with calculation set to automatic and macros
enabled;

• Hard drive with at least 20MB free; and

• Monitor display setting of 800 x 600 or greater.

Microsoft Excel Settings

Excel 2003 and Earlier: For the SIT modules to function properly, Excel must be set to
automatic calculation. To check this setting, launch Microsoft Excel before opening the Coal
module. Go to the Tools menu and select "Options..." Click on the "Calculations" tab and
make sure that the radio button next to "Automatic" is selected, and then click on "OK" to
close the window. The security settings (discussed next) can also be adjusted at this time.

Excel 2007 and Later: For the SIT modules to function properly, Excel must be set to
automatic calculation. Go to the Formulas ribbon and select "Calculation Options." Make
sure that the box next to the "Automatic" option is checked from the pop-up menu.

Microsoft Excel Security

Excel 2003 and Earlier: Because the SIT employs macros, you must have Excel security
set to medium (recommended) or low (not recommended). To change this setting, launch
Microsoft Excel before opening the Coal module. Once in Excel, go to the Tools menu, click
on the Macro sub-menu, and then select "Security" (see Figure 1). The Security pop-up box
will appear. Click on the "Security Level" tab and select medium. When set to high, macros
are automatically disabled; when set to medium, Excel will give you the choice to enable
macros; when set to low, macros are always enabled.

When Excel security is set to medium, users are asked upon opening the module whether to
enable macros. Macros must be enabled in order for the Coal module to work. Once they
are enabled, the module will open to the control worksheet. A message box will appear
welcoming the user to the module. Clicking on the "x" in the upper-right-hand corner of the
message box will close it.

Excel 2007 and Later: If Excel's security settings are set at the default level a Security
Warning appears above the formula box in Excel when the Coal module is initially opened.
The Security Warning lets the user know that some active content from the spreadsheet has
been disabled, meaning that Excel has prevented the macros in the spreadsheet from
functioning. Because SIT needs macros in order to function properly, the user must click
the "Options" button in the security message and then select, "Enable this content" in the
pop-up box. Enabling the macro content for the SIT in this way only enables macros
temporarily in Excel but does not change the macro security settings. Once macros are

State Greenhouse Gas Inventory Tool User's Guide for the Coal Module

1.2

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Module 5 - Coal Module

January 2022

enabled, a message box will appear welcoming the user to module. Click on the "x" in the
upper right-hand corner to close the message box.

If the Security Warning does not appear when the module is first opened, it may be
necessary to change the security settings for macros. To change the setting, first exit out
of the Coal module and re-launch Microsoft Excel before opening the Coal module. Next,
click on the circular "Office Button" in the top left of the screen. At the bottom of the menu,
select the "Excel Options" button to the right of the main menu. When the Excel Options box
appears, select "Trust Center" in left hand menu of the box. Next, click the gray "Trust
Center Settings" button. When the Trust Center options box appears, click "Macro Settings"
in the left-hand menu and select "Disable all macros with notification." Once the security
level has been adjusted, open the Stationary Combustion module and enable macros in the
manner described in the preceding paragraph.

Viewing and Printing the SIT

The Coal module contains some features to allow users to adjust the screen view and the
appearance of the worksheets when they are printed. Once a module has been opened, you
can adjust the zoom by going to the Module Options Menu, and either typing in a zoom
percentage or selecting one from the drop-down menu. In addition, data may not all
appear on a single screen within each worksheet; if not, you may need to scroll up or down
to view additional information.

You may also adjust the print margins of the worksheets to ensure that desired portions of
the Coal module are printed. To do so, go to the File menu, and then select "Print Preview."
Click on "Page Break Preview" and drag the blue lines to the desired positions (see Figure
2). To print this view, go to the File menu, and click "Print." To return to the normal view,
go to the File menu, click "Print Preview," and then click "Normal View."

Figure 1. Changing Security Settings

Figure 2. Adjusting Print Margins

D Microsoft Excel - Bookl

Sj File Edit View

Insert Format

Spelling.,.
jQI Research...
"4> Error Checking...

lools | Data Window Help

Shared Workspace.,,

Share Workbook.,,

Track Changes

Compare and Merge Workbooks...

Protection

Online Collaboration

Goal Seek.,,

Scenarios...

Formula Auditing

Add-Ins...

AutoCorrect Options...

Customize...

Options,..

Macros...

Record New Macro...

.£] Visual Basic Editor Alt+Fll

GG Microsoft Script Editor Alt+Shift+Fll

Pa(§!j

4. Export the results for use in the Synthesis Tool.

~ H\Control / CH4 from Coal Mining / CH4 from Abandoned Coal Mines / Summary Abandoned Coal Mines / Abandoned Data / S

1.2 Module Overview

This User's Guide accompanies and explains the Coal module of the SIT. The SIT was
developed in conjunction with EPA's Emissions Inventory Improvement Program (EIIP).

State Greenhouse Gas Inventory Tool User's Guide for the Coal Module

1.3

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Module 5 - Coal Module

January 2022

Prior to the development of the SIT, EPA developed the States Workbook for estimating
greenhouse gas emissions. In 1998, EPA revisited the States Workbook and expanded it to
follow the format of EIIP guidance documents for criteria air pollutants. The result was a
comprehensive, stepwise approach to estimating greenhouse gas emissions at the state
level. This detailed methodology was appreciated by states with the capacity to devote
considerable time and resources to the development of emission inventories. For other
states, the EIIP guidance was overwhelming and impractical for them to follow from scratch.
EPA recognized the resource constraints facing the states and developed the SIT. The ten
modules of the SIT corresponded to the EIIP chapters and attempted to automate the steps
states would need to take in developing their own emission estimates in a manner that was
consistent with prevailing national and state guidelines.

Because most state inventories developed today rely heavily on the tools, User's Guides
have been developed for each of the SIT modules. These User's Guides contain the most
up-to-date methodologies that are, for the most part, consistent with the Inventory of U.S.
Greenhouse Gas Emissions and Sinks. Volume VIII of the EIIP guidance is a historical
document that was last updated in August 2004, and while these documents can be a
valuable reference, they contain outdated emissions factors and, in some cases, outdated
methodologies. States can refer to Volume VIII of the EIIP guidance documents if they are
interested in obtaining additional information not found in the SIT or the companion User's
Guide.

The Coal module calculates methane (Cl-U) emissions from coal mining and abandoned coal
mine activities. While the module provides default data for calculating mining, post-mining,
and abandoned-mine emissions, if you have access to more comprehensive data sources,
they should be used in place of the default data. If using outside data sources, or for a
more thorough understanding of the tool, please refer to the following discussion for data
requirements and methodology.

1.2.1 Data Requirements

To calculate ChU emissions from coal mining and abandoned coal mines, the data listed in
Table 1 are required inputs (again, note that defaults are available for most of these data).

State Greenhouse Gas Inventory Tool User's Guide for the Coal Module

1.4

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Module 5 - Coal Module

January 2022

Table 1: Required Data Inputs for the Coal Module

Coal Module Sectors

Input Data Required

ChU from Coal Mining



Surface Mining
Activities

Basin-specific emission factors (ft3 ChU / short ton coal)
Surface coal production, by year and basin C000 short
tons)

Underground Mining
Activities

Measured ventilation emissions, by year (million ft3)
Degasification system emissions, by year (million ft3)
CH4 recovered from degasification systems and used for
energy, by year (million ft3)

Surface Post-Mining
Activities

Basin-specific emission factors (ft3 ChU / short ton coal)
Surface coal production, by year and basin C000 short
tons)

Underground Post-
Mining Activities

Basin-specific emission factors (ft3 ChU / short ton coal)
Underground coal production, by year and basin C000
short tons)

CH4 from Abandoned Coal
Mines

A list of abandoned coal mines with the following

information for each:

•	Mine name or number

•	County of location

•	Coal rank (bituminous, sub-bituminous, or anthracite)
or basin

•	Year abandoned

•	CH4 emissions at time of abandonment (million cubic
feet per day)

•	Current status of mine (venting, sealed, or flooded)

•	Percent sealed (choose among 50%, 80%, and 95%
sealed)

•	CH4 recovered (cubic meters per year)

1.2.2 Tool Layout

Because there are multiple steps to complete within the Coal module, it is important to
understand the module's overall design. The layout of the Coal module and the purpose of
its worksheets are presented in Figure 3.

Figure 3. Flow of Information in the Coal Module*

Control Worksheet



Individual Sector Worksheets

1. Choose a State



3. CH+from Coal Mining





Enter measured ventilation emissions, degasification system emissions,

2. Enter emission factors by basin:

>0

methane recovered from degasification systems and used for energy

Surface Mining

and coal production

Underground Post-Mining



4. CH4 from Abandoned Coal Mines

Surface Post-Mining /



Enter information about abandoned underground coal mines, including year

/



abandoned, coal rank/basin name, and emissions at time of abandonment

3.-4. Complete Sector Worksheets





5. View Summary Data <	

	>

Summary Data





i Presented in both table and graphical formats in MTC02E

6. Export Data



— Uncertainty





Review information on uncertainty associated with the default data

* These worksheets are the primary worksheets used in the Coal module; subsequent worksheets are used to
populate the default data and are provided for informational purposes only.

State Greenhouse Gas Inventory Tool User's Guide for the Coal Module

1.5

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Module 5 - Coal Module

January 2022

1.3 Methodology

This section provides a guide to using the Coal module of the SIT to estimate ChU emissions
from coal mining and abandoned coal mines. Within the Coal module, there are two main
categories of emissions: emissions from mining and post mining activities, and emissions
from abandoned underground coal mines. Because the methodology varies considerably by
source, the details of each will be discussed in its respective step, following this general
methodology discussion.

The Coal module will automatically
calculate emissions after you enter
the emission factors on the control
worksheet and the required data
on the individual sector
worksheets. The tool provides default data; however, other state-specific data may be used
if available (see Box 1 for suggestions on where to find data).

The Coal module follows the general methodology outlined in the EIIP guidance; however,
because of the automation of the calculations within the tool, the order of steps discussed in
this User's Guide do not follow the order of steps discussed within the EIIP guidance
document. This User's Guide provides an overview of the estimation methodology used in
the Coal module by walking through the following six steps: (1) select a state; (2) enter
emission factors; (3) complete worksheet for ChU from coal mining; (4) complete worksheet
for ChU from abandoned underground coal mines; (5) review summary information; and (6)
export data.

Step (1) Select a State

To begin, select the state you are interested in evaluating. By selecting a state, the rest of
the tool will automatically reset to reflect the appropriate state default data and
assumptions for use in subsequent steps of the tool.

Step (2) Enter Emission Factors

Step 2 on the control worksheet involves either selecting the default data provided or
entering user-specified emission factors that will be used throughout the tool. To proceed
with the default data, select the "Check / Uncheck AN" button or check the default box
directly to the right of individual yellow input cells. Note that this number can be
overwritten if you discover that the data for your state differ from the default data provided
by the tool. To enter user-specified inputs, enter data directly into the yellow input cells. If
the user-specific inputs do not match the default data in the control worksheet (i.e., the
default value is overwritten), the text will appear red. See Figure 4 for locations of the
"Check / Uncheck AN" buttons, individual default check boxes, and yellow input cells.

Box 1: State Coal Mining Data Sources

In-state sources, such as state departments of energy,
natural resources, or mines, should be consulted first.
Otherwise, default data provided by the Coal module may be
used.

State Greenhouse Gas Inventory Tool User's Guide for the Coal Module

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Module 5 - Coal Module

January 2022

Figure 4. Control Worksheet for the Coal Module

E3 State Inventory Tool - Methane Emissions from Coal Mining

File Edit Module Options

State Inventory Tool - Methane Emissions from Coat Mining

Consult Guidonee

1. Choose a State. Colorado

This is very important - it selects tfie

Required Data

2. Enter Emission Factors

Either type in the value or click the default box.

(ft methane /
short ton coal)

66.2
0.0

Coal Mining Emission Factors (ER
Mines

Surface Mines

SouthwestfRockies (CO)

Post-Mining Activities
Underground

Rockies (Piceance)

Surface

SouthwestfRockies (CO)

3. Proceed to the Coal Mining worksheet.

4. Proceed to the Abandoned Coal Mines worksheet.

5ult Factor Factor Used Use Default?

(ft3 methane / (Check for
short ton coal) VesJ

Check / Uncheck

Select All Defaults

108
0.0

Individual Default
Data Check Boxes

Click to continue to
CHt from Coal Mining
Worksheet ,

Click to continue to ^
CHtfrom Abandoned
Coal Mines

Worksheet /

5. Proceed to Summary worksheet for emissions summary for Colorado.

n 4 ~ h \ Control / CH4 from Coal Mining / CH4 from Abandoned Coal Mines / Summary Abandoned Coal Mines / Abandoned Data / Suit

Surface Mining Activities

The emission factors for surface mining activities entered on the control worksheet are
specific to each coal basin and type of mine (underground or surface). The default emission
factors from U.S. EPA (2005, 2021) are in cubic feet of ChU per short ton of coal. As
discussed in further detail in Step 3, estimating ChU emitted from surface mining involves
multiplying the quantity of surface-mined coal from each coal basin in a state by the
appropriate emission factor for that basin (see Box 2 for a discussion of coal basins). The
emission factor accounts for ChU liberated from the coal itself and from surrounding strata.

Post-Mining Activities

The next step on the control worksheet requires emission factors for post-mining activities
from both underground and surface mines. These emission factors, like those for surface
mining activities, are specific to each coal basin and type of mine (underground or surface).
These emission factors are later used in the Coal Mining sector worksheet to estimate ChU
emissions. The default emission factors are from U.S. EPA (2005, 2021). Once you have
entered emission factors for surface mining activities and for post-mining activities, use the
gray arrows to navigate to the Coal Mining worksheet.

State Greenhouse Gas Inventory Tool User's Guide for the Coal Module

1.7

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Module 5 - Coal Module

January 2022

Box 2: Coal Basin and Rank

Coal is a combustible sedimentary rock formed by the geologic metamorphosis of prehistoric plant
materials. Differences in the origins of the sedimentary plant material combined with differing
amounts of temperature and pressure acting on the rocks in different areas mean that the
characteristics of coal vary from place to place. A basin is a geologic feature that contains a single
large coal deposit. While the coal in a basin can vary from place to place, generally it has a number of
characteristics in common, including rank.

The most basic difference among types of coal is that of coal rank. The four major coal ranks, in order
of increasing purity, are lignite, sub-bituminous, bituminous, and anthracite. Anthracite, as the purest
form of coal, is almost entirely carbon, while lower ranks of coal have more and more impurities such
as sulfur and ash, with lignite being the least pure. Increased rank also generally goes hand-in-hand
with increased heating value, although anthracite has a slightly lower heating value than bituminous
coal, on average.

Although the coal within a basin is generally of only one rank, the characteristics of the coal vary
within a basin, often even from mine to mine. This module calculates emissions based on emission
factors that are based on known characteristics of the following basins: Northern Appalachian, Central
Appalachian Basin, Warrior, Illinois, Piceance, Uinta, San Juan, Green River, Raton Mesa, North Great
Plains, Forest City, Cherokee, Arkoma, Gulf Coast, Alaska, and Washington. These basins were the
smallest scale for which complete information was available for use in the tool and provide a
reasonable approximation of the characteristics of the coal within them.

Abandoned Underground Coal Mines

There are no required inputs for abandoned coal mines on the control worksheet. Because
the Abandoned Coal Mines sector involves complicated calculations, the gray navigational
arrow on the control worksheet takes you directly to the Abandoned Coal Mines worksheet.

Step (3) Complete Worksheet for ChU from Coal Mining

The ChU from coal mining worksheet is divided into emission calculations for underground
and surface activities for active mines and post-mining activities.

Underground Mining Activities

There are two sources of emissions from underground mining: (1) ChU emitted from
underground ventilation systems and (2) ChU emitted from degasification systems.

Emissions from underground ventilation systems are calculated by summing the ChU
emissions from ventilation systems at each underground mine in the state. Emissions from
CH4 degasification systems are calculated by summing reported or estimated emissions of
ChU from all mines with degasification systems in the state, and then subtracting the ChU
that is recovered and used for energy purposes. Figure 5 shows where to enter these data
in the purple cells. The total ChU emitted from underground mines is the sum of ChU
emissions from ventilation and degasification systems, in million cubic feet. That amount is
converted to metric tons of ChU using a conversion factor of 18.92, and subsequently to
MTCO2E by multiplying by the GWP of ChU. The equation used in the module is shown in
Equation 1. The default mine ventilation and degasification system data used in the tool are
based on emission factors and data found in Mroz et al. (1983), USBM (1986), and U.S. EPA
(2003).

State Greenhouse Gas Inventory Tool User's Guide for the Coal Module

1.8

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Module 5 - Coal Module

January 2022

Equation 1. Emissions from Underground Mining Activity

Emissions (MTCO2E) =

{Measured Ventilation Emissions (million ft3) + [Degasification System Emissions
(million ft3) - CH4 Recovered from Degasification Systems and Used for Energy (million
ft3)]} X 18.92 g/ft3 CH4 X 106 ft3/million ft3 X 10"6 MT/g X 25 (GWP of CH4)

Figure 5. Example of Coal Mining Data Applied in the Coal Mining Worksheet

E State Inventory Tool - Methane Emissions from Coal Mining

~Illl]

File Edit Module Options

Type a question for help

F

H

J

L

3. CH4 from Cool Mining in CO

Click here to
find possible
data sources.

Emissions from Coal Mining are calculated by summing the emissions from underground mines, surface mines, and post-mining
activities, as outlined below and detailed in the Methane Emissions from Coal Mining Chapter of the User's Guide.

-Underground mine emissions are comprised of two parts: methane emitted from ventilation systems and methane emitted from
degasification systems. Emissions from degasification systems are equal to the difference between methane removed through
degasification and methane used for energy purposes.

-Surface mine emissions are the product of surface coal mine production and a basin-specific EF.

-Emissions from post-mining activities, such as transportation and coal handling, are equal to the sum of post-mining emissions

from underground and surface mines; the e(
type specific EF.

-Total emissions from coal mining are the si
both types of mines.

mission? are each calculated as the product of cot

Coal Mining

Emissions from:

Mines

L'noergrcuna Mines-

Required Ventilation
and Degasification
System Data

lines, and post-mining activities at

Coal Basin(s)
(if applicable)

production times a basin and mine-

<

Return to
Control Sheet

Go to Summa
Sheet

Check All Boxes

ueiaun Activity Data?

Methane
Recovered from
Degasification
:gstems and Used
for Energg (mcf)

Emissions
(mcf CH,)

Emissions
(MTCH<)

Required Production

Stufsee Mines

Post-Mining Activitj

Underground Mines Rockies (Piceance)

Surface Coal
Production
('000 short
tons)



Basin-specific
EF (ft'f short
ton)

: - :

8,281

Coal
Production
('000 short
tons)

Surface Mines

Pest-Mining Tc-taf

Southwest/Rockies (CO)

10.621

Emissions
(MTCH,)

Emissions
(MTCOiE)

ft' CH,]

6i

Emission Factors (from
Control worksheet)



=



=



89.083

1.710

35.818







767.021

14,727

308,263

> h \ fnntrnl \ r:H4 frnm rn.il Mininn / TH4 frnm Ahanrinnnrl r rial Minn';	/ Summary Ah anrinnnri rral Minm	/ Ahanrinnnri rata /summary I <

Emissior
(MTCOil

]] ) = | 8.009.32621 = | 172.878] = | 3.632.5i

Surface Mining Activities

CH4 emissions from surface mines are estimated by multiplying the state's surface coal
production in each coal basin by an emission factor based on the in-situ ChU content for the
surface coal found in each coal basin. The result is converted to metric tons of Chk, by
dividing by 1,000 and multiplying by a conversion factor of 18.92. That amount is
converted to MTCO2E by multiplying by the GWP of ChU. Figure 5 indicates the purple cells
where you enter the data on surface coal production in '000 short tons, while Equation 2
shows the equation the module uses to calculate emissions from surface mining activities.

State Greenhouse Gas Inventory Tool User's Guide for the Coal Module

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Module 5 - Coal Module

January 2022

Equation 2. Emissions from Surface Mining Activity

Emissions (MTCO2E) =

Surface Coal Production ('000 short tons) x Basin-Specific Emission Factor (ft3/short
ton) x 18.92 g/ft3 CH4 x 103 ft3/'000 ft3 x 10"6 MT/g x 25 (GWP of CH4)

Post-Mining Activities

Post-mining activity ChU emissions from both surface and underground mines are calculated
in essentially the same manner as emissions from surface mining activity, as Equation 3
shows. The U.S. EPA estimates that Chk emitted during post-mining activities, such as
transportation and handling of coal, equals 33 percent of the in-situ ChU content for the coal
(U.S. EPA 1993). U.S. EPA has used this formula to develop post-mining emission factors,
which are used in the module. Figure 5 indicates the purple cells where you should enter
the data on surface and underground coal production in '000 short tons.

Equation 3. Emissions from Post-Mining Activity

Emissions (MTCO2E) =

Coal Production ('000 short tons) x Basin- and Mine-Specific Emission Factor (ft3/short
ton) x 18.92 g/ft3 CH4 x 103 ft3/'000 ft3 x 10"6 MT/g x 25 (GWP of CH4)

Once you have entered the required data on the sector worksheet for each year, the module
calculates and totals the emissions from surface mining, underground mining, and post-
mining activities. After you have completed the ChU from coal mining sector worksheet, use
the gray navigational arrow to return to the control worksheet and proceed to the
worksheet for emissions from abandoned coal mines.

Step (4) Complete Worksheet for CH4 from Abandoned Underground Coal
Mines

The methodology for determining emissions from abandoned underground coal mines is
based on an EPA White Paper, Proposed Methodology for Estimating Emission Inventories
from Abandoned Coal Mines (Franklin et al. 2004). The module uses a database of
abandoned coal mines by state provided in that white paper. Because the methodology is
complex, it is explained in detail in the worksheet itself (in the abandoned underground coal
mines worksheet, click the button "Click here to view more about the methodology"). Note
that the methodology described in this section is only applicable to underground mines, not
to surface mines.

For all abandoned mines, ChU emissions decline as a function of time; this decline can be
calculated by a decline equation representing a decline curve. The decline curves vary
based on the time since abandonment, the nature of the coal seam, and the status of the
mine (vented, sealed, or flooded), as follows:

• A vented mine is one that can release ChU to the atmosphere freely. The emissions
of such a mine will depend only on time since abandonment and coal characteristics.

• A sealed mine has been sealed to prevent the escape of ChU. However, given the
nature of rock used to seal mines, such sealing is never 100 percent effective. The

State Greenhouse Gas Inventory Tool User's Guide for the Coal Module

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Module 5 - Coal Module

January 2022

effect of a seal is not to prevent ChU emissions, but to slow them—to spread them
out over a longer period.

• A completely flooded mine releases little to no Chk to the atmosphere. After a mine
is abandoned, if it is in an area prone to flooding, it will gradually fill up with water.
Therefore, most emissions will occur in the first few years following abandonment,
dropping off quickly as the mine floods.

The decline equations for each of these three statuses are shown in Equation 4.

Equation 4: Emissions from Abandoned Mines

Vented: q = qi x (1 + aT)b
Sealed: q = qi x (l-c)*(l + aT)b
Flooded: q = qi x e( DT)

Where,

q = current emission rate, m3/yr
qi = emission rate at abandonment, m3/yr
a = constant unique to each decline curve
b = constant unique to each decline curve
T = time since abandonment, yr

c = degree of sealing of the mine (50%, 80%, or 95%)
D = decline rate, fraction per year (given as -0.672)

Emissions are calculated separately for each status of mine in a state, using the decline
equations and constants listed in Equation 4. The coal rank, based on the coal basin location
of the mine, is used to determine which values of "a" and "b" to use (values of "a" and "b"
are built into the module). The module then adds emissions from each status of mine
together, along with emissions from mines of unknown status.

Using the Default List of Mines

The module provides a default list of abandoned mines for your state, including information
on coal basin, year abandoned, emissions, and status. The source for the default list of
mines is the U.S. GHG Inventory (EPA 2021). To complete this worksheet, follow these
steps:

1. Choose whether to use the default mine status; if you have more detailed
information about the status of a mine than the module provides, you may
change or overwrite the mine status displayed in the green cells. To select
the default status for all mines, click the check box at the top of the
worksheet, as shown in Figure 6.

2. Choose whether to use the default percent sealed for mines of sealed status.
Again, if you have more detailed information about the status of a mine than
the module provides, you may change or overwrite the mine status displayed
in the green cells—choosing among 50%, 80%, or 95% sealed. Figure 6
shows the location of the cells and of the default check boxes.

State Greenhouse Gas Inventory Tool User's Guide for the Coal Module

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Module 5 - Coal Module

January 2022

3. At some mines, ChU emissions are collected through a degasification system,
and flared or burned to generate electricity. Enter information on amount of
CH4 recovered at each mine as shown in Figure 6. Unfortunately, default
information is not available about the amount of gas recovered at each mine.

Figure 6. Example of Default Data Applied in the Abandoned Coal Mines Worksheet

E3 State Inventory Tool - Methane Emissions from Coal Mining

File Edit Module Options

-Different coal seams vary in the amount of gas present initially and the way the methane is adsorbed to the coal (i.e. some coals
release methane more readily than others).

-A vented mine is one that can release methane to the atmosphere freely. The emissions of vented mines will depend on time
since abandonment and coal characteristics.

-A sealed mine has been sealed to prevent the escape of methane,
such sealing is never 100 percent effective. The effect of a seal ist
longer period of time.

-After a mine is abandoned and in a flood prone area, the mine will fil
no methane to the atmosphere. Therefore, most emissions will occui

Default status and
percent sealed check
boxes

nines,
ver a

s little to

Return to
SControl Sheet

Go to Summary
Sheet

Type a question for help

"/¦. i

ir state J7 Def

ult percent s

a led?

Methane

Percent

Recovered

Actual Status

Sealed

(m'ljr)

Sealed

soy.

Sealed

soy.

Sealed

soy.

Sealed

SOy.

Sealed

soy.

Venting

Sealed

SOy.

Sealed

so y.

SOy.

bealed

so y.

Flooded

Sealed

SO y.

Unknown

Sealed

soy.

Unknown

Sealed

Unknown—.

soy.

Unknown

Sealed

soy.

k here to create a list of abandoned coal mines within your state

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Including Additional Abandoned Mines

If you have information on additional abandoned mines in your state that aren't provided in
the default data from EPA 2021, you may add this information by clicking on the "+" sign
next to "Additional Abandoned Coal Mines" and entering the required data as shown in
Figure 7. Once this sector worksheet is complete, use the gray navigational arrow to return
to the control worksheet and then proceed to the summary worksheet. You may also use
one of the gray navigational arrows at the top to view a summary worksheet for the
abandoned coal mines sector before proceeding to the general summary sheet.

State Greenhouse Gas Inventory Tool User's Guide for the Coal Module

1.12

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Module 5 - Coal Module

January 2022

Figure 7. Example of Additional Data Applied in the Abandoned Coal Mines

Worksheet

E State Inventory Tool -

Methane Emissions from Coal Mining

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m Abandoned Mines in CO

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\£ontrol Sheet

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Sheet ys

Emissions from Abandoned Coal Mines are calculated by summing the emissions from mines that are vented, sealed, or flooded.

-Different coal seams vary in the amount of gas present initially and the way the methane is adsorbed to the coal (i.e. some coals
release methane more readily than others).

-A vented mine is one that can release methane to the atmosphere freely. The emissions of vented mines will depend on time

f Clickhere \
( to view
\ default J

-A sealed mine has been sealed to prevent the escape of methane. However given the nature of the rock used to seal mines,
such sealing is never 100 percent effective. The effect of a seal is to slow the methane emissions to spread them out over a

Clear All Data

longer period of time.

-After a mine is abandoned and in a f

no methane to the atmosphere. There

Enter required data for
any abandoned mines not

jtely flooded mine releases little to
owing abandonment.

Abandoned Cool Mines piease eiiek here to vic^^fouit

j*' Default mine status?
let of ai^.Honcd cool mines within your state W Default percent sealed?

199

aba

200

Additional Abandoned Coal Mi^cs rk«se eikk he*

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ndont? -oal mines within your state

201

202

Mine

Countg

Year
Abandoned

Status

pl^at,
SealeB^

Emissions
L (mmcfd)

Methane
Recovered
(m'lgr)

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11.

12.

13.

14.

15.

16.

17.

18.

19.

20.

21.

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212

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Step (5) Review Summary Information

The steps above provide estimates of total Chk emissions from coal mining and abandoned
coal mines. The information from both worksheets is presented on the summary
worksheet, which displays results in metric tons of carbon dioxide equivalent (MTCO2E) and
metric tons of ChU (MTChU). Figure 8 shows the summary worksheet. In addition, the
results are displayed in graphical format at the bottom of the summary worksheet.

State Greenhouse Gas Inventory Tool User's Guide for the Coal Module

1.13

-------
Module 5 - Coal Module

January 2022

Figure 8. Example of the Emissions Summary Worksheet in the Coal Module

E3 State Inventory Tool - Methane Emissions from Coal Mining















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3



Summary of Emissions from Default Abandoned Coal Mines



4

5

6



Mine Status (without Unknown Distributed;

Emissions (MTCOjE/Year) 1990 1991

1992

1993

1994

1995

199*

1997

1998

1999

200



7

8

9

10



Vented 40,975
Sealed 104,920
Flooded
Unknown 79,277

37,508
92,964

62,624

34,868
85,145

53,486

32,767
152,140

47,946

31,040
131,862

44,300

29,587
120,063

41,709

28,341
111,769

39,738

27,256
219,078

95,954

26,300 25,448
189,311 190,534
25,972 13,253
75,010 63,822

24,68:
174,81 C
6,76:
57,22:



11

18

19



Total 225,173
Mine Status (with Unknown Distributed)

Emissions (MTCOsE/Year) 1990

193 097
1991

173 500
1992

232,852
1993

207,202
1994

191 359
1995

179,848
199$

342,288
1997

316,593 293,057
1998 1999

263,47$
200



20

21

22



Vented 40,975
Sealed 178,535
Flooded 5,663

37,508
151,115
4,473

34,868
134,811
3,820

32,767
196,661
3,425

31,040
172,998
3,164

29,587
158,793
2,979

28,341
148,669
2,838

27,256
308,178
6,854

26,300 25,448
258,963 249,797
31,330 17,812

24,68:
227,94f
10.85C



23

29

30



Total 225,173

193 097

173 500

232,852

207,202

191 359

179,848

342,288

316,593 293,057

263,47$



31



Summary of Emissions from Additional Abandoned Coal Mines



32

33

34



Mine Status

Emissions (MTCOjE/Year) 1990

1991

1992

1993

1994

1995

199*

1997

1998

1999

200



35

36

37



Vented - ..........

Sealed - ..........

Flooded - ..........



38

44

45

46

47

48
~49|
50



Total























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CH4 from Abandoned Coal Mines V Summarv Abandoned Coal Mines i Abandoned Data / Summarv 1 <



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1

Step (6) Export Data

The final step is to export the summary data. Exporting data allows the estimates from
each module to be combined later by the Synthesis Module to produce a comprehensive
GHG inventory for the state.

To access the "Export Data" button, return
to the control sheet and scroll down to the
bottom (step 6). Click on the "Export Data"
button and a message box will open that
reminds the user to make sure all steps of
the module have been completed. If you
make any changes to the Coal module later,
you will then need to re-export the results.

Clicking "OK" prompts you to save the file.

The file is already named, so you only need
to choose a convenient place to save the file. After the file is saved, a message box will
appear indicating that the data was successfully exported.

While completing the modules, you are encouraged to save each completed module; doing
so will enable you to easily make changes without re-running it entirely.

Note: the resulting export file should not be
modified. The export file contains a summary
worksheet that allows users to view the results, as well as
a separate data worksheet with an unformatted version of
the results. The second worksheet, the data worksheet,
contains the information that is exported to the Synthesis
Tool. Users may not modify that worksheet.
Adding/removing rows, moving data, or making other
modifications jeopardize the ability of the Synthesis
Module to accurately analyze the data.

State Greenhouse Gas Inventory Tool User's Guide for the Coal Module

1.14

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Module 5 - Coal Module

January 2022

Following data export, the module may be reset and run for an additional state.
Alternatively, you may run the remaining modules of the SIT to obtain a comprehensive
profile of emissions for your state.

1.4 Uncertainty

In the upper right-hand corner of the summary worksheet is a button: "Review discussion of
uncertainty associated with these results." By clicking on this button, you are taken to a
worksheet that discusses the uncertainty surrounding the activity data and emission factors,
and how the uncertainty estimates for this source category affect the uncertainty of the
emission estimates for your state.

1.5 References

Franklin, P., E. Scheehle, R.C. Collings, M.M. Cote, and R.C. Pilcher. 2004. White Paper:
Proposed Methodology for Estimating Emission Inventories from Abandoned Coal Mines.
U.S. EPA, Prepared for 2006 IPCC Greenhouse Gas Inventories Guidelines Fourth
Authors Experts Meeting. Energy: Methane Emissions for Coal Mining and Handling,
Arusha, Tanzania.

Mroz, T.H., Ryan, J.G., and Bryer, C.W. 1983. Methane Recovery from Coalbeds: A

Potential Energy Source. Report prepared for U.S. Department of Energy. DOE/METC/
83-76.

USBM. 1986. Circular 9067, Results of the Direct Method Determination of the Gas
Contents of U.S. Coal Basins. U.S. Bureau of Mines.

U.S. EPA. 2021. Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 - 2019.
Office of Atmospheric Programs, U.S. Environmental Protection Agency. Available at:
https://www.epa.aov/ahaemissions/inventorv-us-areenhouse-aas-emissions-and-sinks-
1990-2019

U.S. EPA. 2005. Surface Mines Emissions Assessment, U.S. EPA Draft Report, November
2005.

U.S. EPA. 2003. Methane Emissions Estimates & Methodology for Abandoned Coal Mines in

the U.S. Draft Final Report. Washington, DC. June 2003.

U.S. EPA. 1993. Anthropogenic Methane Emissions in the United States: Estimates for
1990. Report to Congress. U.S. Environmental Protection Agency, Office of Air and
Radiation. EPA 430-R-93-003. April. Washington, DC.

State Greenhouse Gas Inventory Tool User's Guide for the Coal Module

1.15

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