Mining Contract: Practical Risk Assessment Guidelines for Identifying, Assessing, and Mitigating Stored Energy Hazards in Underground Coal Mines During and After a Mine Emergency
This contract will determine appropriate and practical risk analysis techniques for assessing and mitigating basic types of possible stored energy sources for currently available communication, tracking, and atmospheric monitoring systems (AMS), along with a list of recommendations, procedures, and guidelines on which stored energy sources need to be de-energized and which ones do not, based on the type and location of the mine emergency.
Contract Status & Impact
The contract is complete. To receive a copy of the final report (consisting of the 4-volume set below), send a request to OMSHR@cdc.gov.
There were four basic tasks associated with this project:
- Task 1 - conduct a background document review of mine accidents associated with electrical hazards, batteries, communication, tracking, and atmospheric monitoring systems, and related MSHA regulations.
- Task 2 - review applicable MSHA and other regulations related to electrical safety issues in underground coal mines.
- Task 3 - summarize recent (past 40 years) underground coal mine disasters and attempt to identify the underlying causes(s) of the accidents based on historical MSHA reports.
- Task 4 - perform an appropriate risk/hazard analysis based on the background data, MSHA regulations, and mine disaster information (Tasks 1-3), develop and deliver a user-editable Microsoft Access risk assessment database, and provide recommendations for improving low-voltage electrical safety in underground coal mines.
The contractor provided the following deliverables (four volumes and a database), which are described in further detail below:
- Volume 1 - Background Research Summary for Stored Electrical Hazards in Underground Mines.
- Volume 2 - Mine Power Systems Used in Conjunction With DC Power Generation and Battery Usage.
- Volume 3 - Incident Analyses - Hazardous Energy, PPE, Ventilation and Monitoring.
- Volume 4 - Practical Risk Assessment and Recommendations.
- Database - Risk Assessment for Stored Energy (Microsoft Access database) - user-editable.
Volume 1 - Background Research Summary for Stored Electrical Hazards in Underground Mines
The contractor first did a background review summary of recent previous NIOSH contract work on the following topics and summarized them in this volume:
- Mine accidents with an emphasis on electrical hazards.
- Batteries used in underground coal mines and specific types of battery chemistries.
- Communications and tracking systems used in underground coal mines.
- Atmospheric monitoring systems (AMS).
- MSHA regulations pertinent to electrical safety in underground coal mines.
- Electrical safety hazards in underground coal mines.
Volume 2 - Mine Power Systems Used in Conjunction With DC Power Generation and Battery Usage
The contractor next reviewed all applicable MSHA regulations relating to electrical safety issues in underground coal mines. This volume:
- summarizes the basic electrical systems used in underground coal mines.
- presents hazardous atmosphere zoning classifications.
- discusses MSHA regulations as they apply to low-voltage underground mine electrical systems.
Volume 3 - Incident Analyses - Hazardous Energy, PPE, Ventilation and Monitoring
The contractor next conducted a root cause analysis of recent mine disasters associated with electrical failures to determine any linkage between the root cause of the problem and an associated electrical component failure. This volume:
- summarizes recent historical underground coal mine disasters relevant to the current work effort and attempts to identify the underlying cause(s) of the accidents from historical reports.
- summarizes electrical safety issues in general industry and also in other countries including hazardous energy control and personal protective equipment (PPE).
- includes current MSHA regulations related to ventilation and suggestions to improve these regulations (ventilation was addressed because it has played a key role in a large number of historic mine electrical disasters).
Volume 4 - Practical Risk Assessment and Recommendations
Based on the information in Volumes 1-3, the contractor developed the risk and hazard analysis based on FMEA (failure mode and effects analysis) and associated control measures, which are documented in this volume.
Database - Risk Assessment for Stored Energy (Microsoft Access database)
The contractor set up an editable, user-friendly risk assessment database in Microsoft Access. Various types of electrical equipment used in underground coal mines and related MSHA regulatory data were entered into the database. This database contains over 6,800 data points coded into 24 safety control categories. It contains potential primary, secondary, and tertiary failures for various types of electrical equipment (batteries, chargers, communication and tracking equipment, AMS, cables, grounding, etc.), along with the associated risk severity, likelihood, and qualifying factors. Various reports such as "Summary of Hazards with Risk Rank," "Summary of Control Measures," and "Battery Classifications and Specifications" are available. In addition, there are suggested control measures and estimates of risk reduction assuming that these control measures are implemented.