4
air blasts and sinkhole formation. The most recent incident
in 2021 is described in this paper, emphasizing the sud-
den and destructive nature of air blasts. The optical flow
algorithm is used to estimate air blast velocities by analyz-
ing video footage of pillar collapse incidents. Optical flow
is a computer vision technique that tracks the motion of
objects or features in video frames, allowing the quantifica-
tion of air blast dynamics. Results from the analysis of the
2021 incident video reveal rapid air blast propagation with
peak velocities of 120 mph within seconds, emphasizing
the catastrophic potential of such events.
Proposed future research in this field can be prioritized
in several areas. First, continued data collection and analysis
of pillar collapses and air blasts are essential to refine safety
protocols and mitigation strategies. Additionally, the meth-
ods such as developing ventilation air raised in the mines to
relieve the air blast pressure should be studied. The above-
discussed optical-flow velocity tool currently needs to be
run in Python and does not have a graphical user interface
therefore, it requires knowledge of computer coding to use
it. In order to make this tool more user friendly, a software
is planned to be developed by NIOSH researchers so that
users without coding knowledge can use the tool by just
uploading a video and calculating the velocity of interest.
Furthermore, research efforts through other sections of
the National Institute for Occupational Safety and Health
(NIOSH) are being carried out to protect miners from
imminent pillar collapses and air blasts. Overall, ongoing
research in this field is imperative to safeguard the lives of
miners and reduce the risks associated with pillar collapses
and air blasts in underground stone mines.
6.0 LIMITATIONS
The work completed in this study was from an exploratory
research perspective to evaluate the ability of using surveil-
lance video data to estimate airblast velocities. The veloci-
ties estimated from the video used has not been verified
with any other scientific measurement and should not be
construed as the actual airblast velocity for the event evalu-
ated. Further research efforts, in more controlled environ-
ments, need to be conducted to determine if the advanced
methodologies and algorithms proposed in this study can
be used towards mine accident investigations.
7.0 DISCLAIMER
The findings and conclusions in this report are those of
the authors and do not necessarily represent the official
position of the National Institute for Occupational Safety
and Health, Centers for Disease Control and Prevention.
Mention of any company or product does not constitute
endorsement by NIOSH
Figure 5. Results from the optical flow algorithm
air blasts and sinkhole formation. The most recent incident
in 2021 is described in this paper, emphasizing the sud-
den and destructive nature of air blasts. The optical flow
algorithm is used to estimate air blast velocities by analyz-
ing video footage of pillar collapse incidents. Optical flow
is a computer vision technique that tracks the motion of
objects or features in video frames, allowing the quantifica-
tion of air blast dynamics. Results from the analysis of the
2021 incident video reveal rapid air blast propagation with
peak velocities of 120 mph within seconds, emphasizing
the catastrophic potential of such events.
Proposed future research in this field can be prioritized
in several areas. First, continued data collection and analysis
of pillar collapses and air blasts are essential to refine safety
protocols and mitigation strategies. Additionally, the meth-
ods such as developing ventilation air raised in the mines to
relieve the air blast pressure should be studied. The above-
discussed optical-flow velocity tool currently needs to be
run in Python and does not have a graphical user interface
therefore, it requires knowledge of computer coding to use
it. In order to make this tool more user friendly, a software
is planned to be developed by NIOSH researchers so that
users without coding knowledge can use the tool by just
uploading a video and calculating the velocity of interest.
Furthermore, research efforts through other sections of
the National Institute for Occupational Safety and Health
(NIOSH) are being carried out to protect miners from
imminent pillar collapses and air blasts. Overall, ongoing
research in this field is imperative to safeguard the lives of
miners and reduce the risks associated with pillar collapses
and air blasts in underground stone mines.
6.0 LIMITATIONS
The work completed in this study was from an exploratory
research perspective to evaluate the ability of using surveil-
lance video data to estimate airblast velocities. The veloci-
ties estimated from the video used has not been verified
with any other scientific measurement and should not be
construed as the actual airblast velocity for the event evalu-
ated. Further research efforts, in more controlled environ-
ments, need to be conducted to determine if the advanced
methodologies and algorithms proposed in this study can
be used towards mine accident investigations.
7.0 DISCLAIMER
The findings and conclusions in this report are those of
the authors and do not necessarily represent the official
position of the National Institute for Occupational Safety
and Health, Centers for Disease Control and Prevention.
Mention of any company or product does not constitute
endorsement by NIOSH
Figure 5. Results from the optical flow algorithm
