Earth Conductivity Estimation from Through-the-Earth Measurements of 94 Coal
Mines Using Different Electromagnetic Models
#MMPMID26213457
Yan L
; Waynert J
; Sunderman C
Appl Comput Electromagn Soc J
2014[Oct]; 29
(10
): 755-762
PMID26213457
show ga
Through-the-Earth (TTE) communication systems require minimal infrastructure to
operate. Hence, they are assumed to be more survivable and more conventional than
other underground mine communications systems. This survivability is a major
advantage for TTE systems. In 2006, Congress passed the Mine Improvement and New
Emergency Response Act (MINER Act), which requires all underground coal mines to
install wireless communications systems. The intent behind this mandate is for
trapped miners to be able to communicate with surface personnel after a major
accident-hence, the interest in TTE communications. To determine the likelihood
of establishing a TTE communication link, it would be ideal to be able to predict
the apparent conductivity of the overburden above underground mines. In this
paper, all 94 mine TTE measurement data collected by Bureau of Mines in the 1970s
and early 1980s, are analyzed for the first time to determine the apparent
conductivity of the overburden based on three different models: a homogenous
half-space model, a thin sheet model, and an attenuation factor or Q-factor
model. A statistical formula is proposed to estimate the apparent earth
conductivity for a specific mine based on the TTE modeling results given the mine
depth and signal frequency.
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