IEEE Geoscience and Remote Sensing Magazine - September 2019 - 95

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THE HISTORY OF MINING IN CHINA
Geological hazards caused by coal mining are an extremely
important issue in many parts of the world, and they constitute several kinds of problems, such as water inrush in underground tunnels, surface collapse, and settling of roads,
buildings, and other infrastructure. The mine voids are the
main detecting targets. Using seismic and electric sounding methods to locate and image the voids or aquifers of an
abandoned or in-service mine is an effective way to prevent
geological disasters and improve safety on the surface [1]-
[6]. However, unlike the situation in many other countries,
China has been facing a great threat from the hazard of
water inrush in underground mine roadways as a result of
complex geological structures and the increasing depths of
mining. Therefore, several geophysical methods have been
introduced into underground tunnels so that the geophysical equipment can be closer to potentially hazardous areas.
When working on the surface, the seismic method is usually adopted to predict the details of the coal seam [7], but,
in the limited space underground, electrical prospecting is
the main method.
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IEEE GEOSCIENCE AND REMOTE SENSING MAGAZINE

Advance detection predicts the potential hazard zones
in coal seams by applying drilling and geophysical exploration methods. Typically, those zones are located in front
of the driving face or in the seams before coal driving. In
addition, the status of the structure of the surrounding
rocks and the geologic factors resulting in disasters are important critical points for advance prediction. With an average increase in mining depth of 10-20 m/year in China,
coal mines represent serious potential disasters including
gas explosion and rock burst, roof collapse, mine fire, and
inundation. Therefore, the development of geophysical advance-detection technology is of great significance for coal
mine safety [8]-[10]. The production of Chinese coal mines
increased rapidly from 0.894 billion tons in 1986 to 3.75
billion tons in 2015, but the fatality rate (deaths/million
tons) dropped from 7.07 to 0.157. Obviously, advance-detection technologies, which have evolved from simple drilling methods to 3D detection systems combining drilling
and geophysical prospecting, have played an important role
over the past 30 years [11]-[14].
During the 1980s and 1990s, resistivity methods were
widely used in the advance detection of coal mines [15]-
[19], and the electromagnetic wave tomography method
was used to improve the prospecting capability for small
structures in a coal seam [20], [21]. Since 1998, MTEMs
have been widely used in advance detection [22]-[25].
In particular, during the period of 2002-2012, considered
the golden decade of the Chinese coal industry, many people
were engaged in developing underground advance-detection
technologies and equipment. The Chinese central government and coal mine companies provided significant financial support for a variety of mine-based geophysical methods,
techniques, and instruments. From 2005 to 2010, the longdistance advance detection of seismic waves technology and
its equipment were studied with support from the National
Science and Technology Support Program (NSTSP) [26].
The instruments of mine ground-penetrating radar (GPR)
achieved some breakthroughs [27], [28]. From 2011 to 2015,
the NSTSP funded the development of in situ and online
monitoring and early warning systems for water inrush disasters in coal mines, and the National Key Scientific Apparatus
Development of Special Item supported the development of
mine nuclear magnetic resonance equipment [29].
Based on reviewing the electrical prospecting methods
used in advance detection of coal-mining face or heading
face, development trends for advance-detection technologies were projected according to future demands [30].
ELECTRICAL PROSPECTING METHODS
FOR ADVANCE DETECTION
ADVANCE DETECTION OF A HEADING FACE
Chinese regulations for coal mine water prevention and
control require that "wherever there is an excavation,
there must be a detection" [31]. In complex hydrological
environments, a comprehensive surface and underground
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IEEE Geoscience and Remote Sensing Magazine - September 2019

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