# Mining Contract: Universal Mobile Refuge Alternatives Thermal Simulation Modeling Tool

Keywords:Humidity

| Contract #                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | 200-2014-59254 |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------|
| 9/1/2014                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
| 8/31/2016                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
| A universal technology is needed to evaluate and facilitate the safe deployment of any refuge alternative (RA) by manufacturer-specified standards in any underground mine in in situ conditions selected for the siting of the RA. Variations in the in situ environment are wide. Underground coal mines in the US may have cold or hot strata conditions, and seasonal variations in the air and strata temperatures may also affect the criticality of deploying an RA at a mine, turning an acceptable in situ condition in the winter into unacceptable in the summer without corrective deployment measures. |
| - Refuge Chambers                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |

## Contract Status & Impact

This contract is complete. To receive a copy of the final report, send a request to mining@cdc.gov.

The Mine Improvement and New Emergency Response Act (MINER Act) of 2006 mandates the use of emergency rescue chambers in all US coal mines. One solution is the use of a refuge alternative (RA), emplaced within 1,000 feet from the workers, as mandated. NIOSH has conducted research on a particular RA brand, with the results showing that the thermal and humidity environment inside an occupied RA may exceed the threshold of 35 degrees C for the apparent temperature, Ta, within the 96 hours of sheltering time required by the Mine Safety and Health Administration (MSHA) in 30 CFR 7.504. The Ta is calculated using both the temperature and relative humidity in an un-ventilated area.

The current practice for temperature measurement uses physical measurements of the internal temperature of the RA with simulated miners as heaters. The thermal test of an RA is usually conducted either in a building bay or in an underground test facility by the manufacturer. The thermal environment is kept similar to those expected in a mine. However, it is not possible to carry out measurements for the qualification of all RAs at all possible, individual, in situ conditions at all mines. The users of the RAs at the operating mines need a new deployment qualification technique which requires fewer measurements but still provides reliable estimates for applicability at any site.

The contract will develop a new, Universal Deployment Technology (UDT) and within it a Thermal-Humidity-Airflow Model (T-H-A-M) which links the RA with its given specifications to the in situ thermal environment of a given mine. The UDT will assist in rating an RA for safe sheltering of the allowable number of occupants for 96 hours for a given in situ environment at the mine. Currently there is no such support technology available to mines. Deployment of an RA in an inappropriate thermal environment, or the over-rating of its occupational capacity, violates compliance with 30 CFR 7.504. This can be avoided by using the proposed deployment decision technology. In addition, the UDT will quantitatively determine the necessary cooling enhancement to be applied for bringing the RA application in compliance with MSHA regulations.

All of the model elements needed for this research are available from the MULTIFLUX software, owned by the University of Nevada, Reno. All enhancement techniques that the RA may need are on-the-shelf, common to mine ventilation and climate simulation experts. Computer software assembly work is needed to connect the elements of the UDT, to verify it against NIOSH measurements, and to make it user-friendly.

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          - Announcing Two New Sister Publications on Refuge Alternatives
          - Development of Heat Mitigation Systems for Refuge Alternatives used in Underground Coal Mines
          - Effects of Specimen Age on the Uniaxial Compressive Strength and Moisture Content of Weak Coal Measure Rocks
          - Identifying Moisture Sensitive Roof Rocks in Coal Mines
          - Investigation of Temperature Rise in Mobile Refuge Alternatives
          - NIOSH Refuge Alternative Webinar
          - Portable Refuge Alternatives Temperature and Humidity Tests
          - A Study on Effects of Size and Structure on Hygroscopicity of Nanoparticles Using a Tandem Differential Mobility Analyzer and TEM
          - Triboelectric Effects on Polyethylene Methane Drainage Pipelines
          - Validation of Temperature and Humidity Thermal Model of 23-person Tent-type Refuge Alternative

July 18, 2016

October 11, 2014

National Institute for Occupational Safety and HealthMining Program

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