Coal Mine Boundaries and Methane Sources

This document describes new GEM research used to identify coal mine boundaries and potential sources of coal mine methane (CMM). The data from this research can be used to drive CMM attribution and mitigation efforts, particularly when combined with remotely sensed methane plume locations and mine ownership data.

Background

The primary objective of this research is to support the United Nations Environmental Programme’s International Methane Emissions Observatory (IMEO) Steel Methane Programme (SMP) in developing a database of metallurgical coal mine methane emissions and sources. The results of this research will be used for supporting the prioritization of company actions, governments and policymakers in developing and implementing effective methane reduction strategies. The research results will be integrated into GEM’s publicly available Global Coal Mine Tracker and Global Methane Emitters Tracker.

Coal mines inclusion criteria

The IMEO selected two hundred and fifty mines from the Global Coal Mine Tracker that collectively account for approximately 50% of all global metallurgical coal production. The selection captures a broad range of methane management practices, mining methods, mine types, and production volumes. A small number of thermal coal mines were also included to support IMEO Science Studies and to enhance geological diversity to improve understanding of coal mine methane emissions. The full list of mines can be found here.

Research resources

A wide range of publicly available research resources were used in this research, including:

Environmental impact assessment, protection, monitoring and restoration plans or reports
Environmental permit documents
GIS platforms covering mining permits, subsoil use, concessions, geological and economic surveys
Annual reports, reviews and acquisition announcements
Coal resource and reserves reports
Compliance reports and audits
Industry factsheets, presentations and websites
Land reclamation, resource assessment, restoration, rehabilitation and closure reports and plans
Mine design, operation, infrastructure and expansion reports
Mine safety assessments and emergency response plans and reports
Research papers, studies and presentations
Satellite imagery
Water impact, conservation and management plans and reports
GEM’s Global Gas Infrastructure Tracker, Global Coal Plant Tracker, and Global Coal Mine Tracker
CarbonMapper and IMEO methane plume data

Methodology summary

Mine boundaries

Methods used for determining the coordinates of mine boundaries depend on the types of research resources available, which vary from country to country. The boundaries of coal mines were determined using the following methods to construct boundary polygons:

Using explicitly listed mining boundary coordinates. The use of this method was possible mostly for mines in China.
Extracting permit or mine boundary geometries from GIS resources. This method was commonly used for mines in Australia, Kazakhstan and USA for example.
Georeferencing, tracing and geocoding boundaries from images of mining boundaries depicted in maps, figures and diagrams. This method was used for a wide range of mines in different countries.

Estimating boundaries based on the Global Coal Mine Tracker Mine Area (km2) attribute (which was found to correlate well with boundary areas from this research), or visual and coal mine infrastructure information from reports and satellite imagery. This method was occasionally used when suitable research resources could not be identified.

CMM sources

Methods used for determining the coordinates of mine boundaries depend on the types of research resources available, which vary from country to country. The locations of CMM sources were determined using the following methods:

Using explicitly listed infrastructure coordinates. The use of this method was possible mostly for mines in China.
Georeferencing, tracing and geocoding locations of mining infrastructure found in maps, figures and diagrams. This method was used for a wide range of mines in different countries.
Detailed visual inspection of satellite imagery. This method was used for all mines, in addition to the above methods.

Georeferencing and satellite inspection methods were used in conjunction with GIS layers created from GEM’s Global Gas Infrastructure Tracker, Global Coal Plant Tracker, and occasionally the Oil and Gas Infrastructure Mapping (OGIM) database. These were used to ensure that identified methane sources were from coal mine assets and not from colocated energy related operations such as gas fields, or high pressure gas transmission systems. CarbonMapper and IMEO methane plume locations were also used as a tool for checking for potentially missed CMM sources.

Release and external review

During research, results are compiled and released on a weekly basis. To increase the quality and confidence of the research findings:

An early access map of the results was made available for eliciting input from GEM’s Coal Mine Methane NGO network.
CMM and industry expert Ray Pilcher was consulted to provide education on the lifecycle, construction and operation of coal mines, and to validate and improve GEM’s identification of CMM sources.
Members of the IMEO SMP project team provided ongoing validation and input of research results.

Research data architecture

Research data representing mine boundaries and potential CMM sources were collected together for each mine using a standardized structure containing one or more features. Examples of features include mine boundaries, ventilation shafts and gas drainage stations. Each feature consists of a common set of properties:

Feature category and subcategory

Each feature is categorized as a mine boundary, degasification system, ventilation system, or other.

A mine boundary feature subcategory contains information about the type of mining: underground, surface or underground and surface
For degasification system and ventilation system categories, we adopted the definitions from the 'Coal mine methane abatement technologies' section of the IEA's Global Methane Tracker (May 2025).
A degasification system includes subcategories for degasification wells, drainage boreholes, flares, power generation utilizing CMM, compression into LNG, gas drainage stations, and other gas drainage systems.
A ventilation system includes subcategories for ventilation air methane (VAM) exhaust and air intake shafts/fans, VAM oxidation systems, and other ventilation related systems.
The other category allows for other potential CMM sources such as dewatering stations, mine entrances/exits, production shafts, mine drifts, coal preparation and handling plants, and coal storage.

These and other feature categories and subcategories are described in more detail in the data and visual examples dictionary.

Feature description

A short simple description of the feature.

Feature notes

Detailed information about the research resources used in deriving the feature, including extraction methods, detailed citations and web.archive.org links. In cases of inoperable web.archive.org links, copies of resources were made and are available upon request.

Feature information source date

The date of the research resources used in deriving the feature. For CMM sources, this is the date of the most recent satellite imagery tile used in identifying the source.

Feature geometry

Geometries are encoded using Well-Known Text (WKT). Geometry coordinates are stored in the World Geodetic System 1984 (WGS84) coordinate reference system.

Feature geometry precision classification

A classification conveying the accuracy of the feature’s geometry. A value of reported indicates feature coordinates were explicitly listed out in a document. A value of extracted indicates feature coordinates were derived using a process that may introduce some error, such as image georeferencing, using third party GIS sources, or using satellite imagery. A value of estimated is used when feature coordinates were not reported and cannot be extracted, and a proxy was used as an estimation.

Feature metadata

Other metadata including mine owner, parent company, coal grade, GEM Wiki pages and unique feature identifiers.

A visual data dictionary of CMM sources

A data dictionary containing visual examples of CMM sources was created for the following purposes:

Provide a mechanism for early peer review and feedback from coal mine experts and organizations
Provide a repository of examples that can be leveraged for training image recognition algorithms to automate CMM source identification
Provide a resource for training researchers
Provide common language and shared definitions

The visual examples are taken from satellite imagery and photographs, and arranged by categories, subcategories and country.

Correlations with GEM Global Coal Mine Tracker attributes

A good correlation was found between mine boundary areas as of October 24, and the May 2025 Global Coal Mine Tracker ‘Mine Area (km2)’ attribute (R2=0.64, n=148). The relationship was stronger for underground mine types (R2=0.84, n=107), and weaker for surface mines (R2=0.34, n=33). We use this correlation and other statistics based on this research to support the creation of estimated mine boundaries created from the ‘Mine Area (km2)’ attribute. Estimated boundaries for all mines in the Global Coal Mine Tracker can be used in GEM’s Global Methane Emissions Tracker for calculating methane plume intersections and attributions (see GMET methodology for more information). Poor correlations were found between mine boundary areas and both ‘Total Reserves (Proven and Probable, Mt)’ and ‘Production (Mtpa)’ attributes (R2=0.06, n=136, and R2=0.14, n=59 respectively).

Viewing and downloading results data

Explore the latest coal mine boundaries and methane sources research results with the map. Results will be available for download in 2026 at the Global Coal Mine Tracker download page or the Global Methane Emitters Tracker download page.

Please contact [email protected] for more information.