# Mining Contract: Magneto-Inductive TTE Communications

Keywords:Through-the-earth communications systems

| Contract #                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | 200-2009-31292 |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------|
| 8/25/2009                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
| 10/31/2010                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| This contract will fabricate and test through-the-earth (TTE) communication devices in an underground mine. Six magneto-inductive (MI) TTE communication devices will be built according to a plan approved by NIOSH. The modules are digital transceivers supporting both voice and text communications. Wideband mode is used for digital voice and data, while the narrowband, with a longer range, is for data only. Three plug-and-play transmit antennas having different transmission ranges will also be built. They will be tested in an underground mine to evaluate range, functionality in the presence of electrical noise, ease of use, and mechanical ruggedness. A new prototype, handheld, MI direction finder, capable of locating transmitting MI communication devices, will also be demonstrated for possible use in locating trapped miners. A report documenting the results will be delivered, along with an operator's manual describing the equipment operation and servicing procedures. |
| - Emergency Communications and Tracking                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |

## Contract Status & Impact

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

The contract was awarded on August 25, 2009, and a kickoff conference call was held on September 18, 2009. A draft test plan for the prototype system was submitted to NIOSH for review on November 6, 2009. It covered proposed test procedures for two-way underground and surface communications as well as tests for magnetic noise effects, radio interface, and repeater function demonstrations.

The prototype hardware was constructed and tested in the laboratory. Six prototype transceivers and antennas were delivered to Pittsburgh in early May 2010. The units were tested at a commercial mine in southwestern Pennsylvania. Text messages were successfully transmitted two ways at distances up to 800 feet. The contract was extended to allow time to enhance signal reception and mitigate electromagnetic noise effects underground.

Ultra Electronics and NIOSH performed a second round of testing on the TTE Communications system on September 21, 2010, at a commercial coal mine. This testing was conducted to evaluate new developments in transmission antennae and noise filtering, which were included to improve performance in a coal mine environment. Successful real-time voice reception on the surface from an underground transmitter was recorded through better than 600 feet of overburden. Low-speed text communications also demonstrated an improvement in quality.

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          - Adaptive-Noise-Cancellation Techniques for Through-the-Earth Electromagnetics: Volume III
          - Apparent Earth Conductivity Over Coal Mines as Estimated from Through-the-Earth Electromagnetic Transmission Tests
          - Preliminary Performance Predictions For Electromagnetic Through-The-Earth Mine Communications: A Collection of Working Memoranda
          - Propagation of EM Signals in Underground Mines
          - Research and Development Contract for Coal Mine Communication System: Volume 3 - Theoretical Data Base
          - Theoretical Noise and Propagation Models for Through-the-earth Communication
          - Through-The-Earth Wireless Real-Time Two-Way Voice Communications
          - Two-Way, Through-the-Earth Emergency Communication System for Trapped Miners and the Surface
          - Ultra-Low Frequency Through-the-Earth Communication Technology
          - Vertical Magnetic Noise in the Voice Frequency Band Within and Above Coal Mines

July 19, 2016

July 19, 2016

National Institute for Occupational Safety and HealthMining Program

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