607
5.2 Difficulties for construction
In contrast to above-ground facilities, mines are defined in their maximal spatial extent. They
are bound to the place of the deposit and active operations continue to develop dynamically. There are at least two entrances to the mine, sometimes more. However, these shafts or
ramps have a limited cross-section. This limits the maximum dimensions of the equipment
that can be transported underground. The same applies to the mine workings in which they
are used. The transport possibilities in a mine are restricted by the dimensions of the relevant
machines. The equipment must be transportable with the available machinery and be loadable or even drivable. Vibrations or bumps may occur during transport which may cause
damage to the construction or electronics. For the construction of mobile robots, the necessary ground clearance of the device and a suitable mode of transport must also be selected.
Obstacles can be rails, uneven floors, installations and support, standing or flowing water
and rock masses. Mobile devices must have independent power supply, i.e. sufficient battery
capacity. When rechargeable batteries are used, safety during charging must be ensured. The
main hazards here are explosion or ignition of the battery in the event of defects. None of the
devices must block escape routes in the event of a defect. Furthermore, protection of workers
from mechanical hazards such as jamming or falling over of the device must be ensured by
the constructive design in advance.
5.3 Challenges for autonomous navigation
Autonomous driving for street vehicles is already well advanced above ground. However, the
findings can only be applied to a limited extent in autonomous underground navigation. The
biggest difference is the lack of GPS or a similar localization system on an industrial level. As
a minimal requirement any autonomous robot needs information about its surrounding area,
i.e. by the method of laser scans. Its geo-reference inside the mine however is more a nice-tohave feature, from which especially the robots mapping algorithms will benefit. Particularly
in unknown or non-instrumented mine environments, it is a challenge to link the local map
of the robot with the real-world coordinates. A similar problem arises for determining the
exact depth at which the robot is located. Other factors such as the uneven floor, reflections
on water surfaces or changing cross sections, challenge the autonomous navigation. Besides
this independent operation mode, the robots activities may always be overwritten by a human
operator at any given time, ideally remotely either from underground or outside of the mine.
5.4 Data transmission and further processing
The establishment of data networks in mines is much more difficult than in other closed
environments. It is possible to transmit wired data; however, this is only practicable for permanently installed sensors. Due to the continuous dynamic development of the mine and
the mining process, installation and extension work of the corresponding infrastructure is
continuously necessary. The use of wireless networks is also advantageous with regard to
the integration of numerous mobile sensors and devices. However, the expansion of radio
waves underground is massively restricted due to the small cross-sections, massive walls of
rock, unevenness of the walls, supports and installations in the route, layout of the drifts
and others. In some cases, data can only be transmitted over a few meters or, in most cases,
only with a visual connection (line of sight, LOS). The selection of a suitable radio network
is crucial for its performance underground. The use of electromagnetic waves underground
must be checked in advance with regard to explosion protection and blasting work. Through
automation, digitization and monitoring, the number of sensors and therefore the acquired
data increases immensely. The collection and further processing of data must comply with
legal regulations. The extent to which personal data may and must be collected has to be considered in the same way as the anonymization of data in individual cases. The large amounts
of data still pose a problem. In order to manage this, they have to be selected, evaluated,
processed and stored using suitable algorithms. Questions like these have to be solved before
the data acquisition starts.
5.2 Difficulties for construction
In contrast to above-ground facilities, mines are defined in their maximal spatial extent. They
are bound to the place of the deposit and active operations continue to develop dynamically. There are at least two entrances to the mine, sometimes more. However, these shafts or
ramps have a limited cross-section. This limits the maximum dimensions of the equipment
that can be transported underground. The same applies to the mine workings in which they
are used. The transport possibilities in a mine are restricted by the dimensions of the relevant
machines. The equipment must be transportable with the available machinery and be loadable or even drivable. Vibrations or bumps may occur during transport which may cause
damage to the construction or electronics. For the construction of mobile robots, the necessary ground clearance of the device and a suitable mode of transport must also be selected.
Obstacles can be rails, uneven floors, installations and support, standing or flowing water
and rock masses. Mobile devices must have independent power supply, i.e. sufficient battery
capacity. When rechargeable batteries are used, safety during charging must be ensured. The
main hazards here are explosion or ignition of the battery in the event of defects. None of the
devices must block escape routes in the event of a defect. Furthermore, protection of workers
from mechanical hazards such as jamming or falling over of the device must be ensured by
the constructive design in advance.
5.3 Challenges for autonomous navigation
Autonomous driving for street vehicles is already well advanced above ground. However, the
findings can only be applied to a limited extent in autonomous underground navigation. The
biggest difference is the lack of GPS or a similar localization system on an industrial level. As
a minimal requirement any autonomous robot needs information about its surrounding area,
i.e. by the method of laser scans. Its geo-reference inside the mine however is more a nice-tohave feature, from which especially the robots mapping algorithms will benefit. Particularly
in unknown or non-instrumented mine environments, it is a challenge to link the local map
of the robot with the real-world coordinates. A similar problem arises for determining the
exact depth at which the robot is located. Other factors such as the uneven floor, reflections
on water surfaces or changing cross sections, challenge the autonomous navigation. Besides
this independent operation mode, the robots activities may always be overwritten by a human
operator at any given time, ideally remotely either from underground or outside of the mine.
5.4 Data transmission and further processing
The establishment of data networks in mines is much more difficult than in other closed
environments. It is possible to transmit wired data; however, this is only practicable for permanently installed sensors. Due to the continuous dynamic development of the mine and
the mining process, installation and extension work of the corresponding infrastructure is
continuously necessary. The use of wireless networks is also advantageous with regard to
the integration of numerous mobile sensors and devices. However, the expansion of radio
waves underground is massively restricted due to the small cross-sections, massive walls of
rock, unevenness of the walls, supports and installations in the route, layout of the drifts
and others. In some cases, data can only be transmitted over a few meters or, in most cases,
only with a visual connection (line of sight, LOS). The selection of a suitable radio network
is crucial for its performance underground. The use of electromagnetic waves underground
must be checked in advance with regard to explosion protection and blasting work. Through
automation, digitization and monitoring, the number of sensors and therefore the acquired
data increases immensely. The collection and further processing of data must comply with
legal regulations. The extent to which personal data may and must be collected has to be considered in the same way as the anonymization of data in individual cases. The large amounts
of data still pose a problem. In order to manage this, they have to be selected, evaluated,
processed and stored using suitable algorithms. Questions like these have to be solved before
the data acquisition starts.