Transcript Underground In The Cloud

"Underground In The Cloud"
BUMPS
"Underground In The Cloud"
BUMPS
- Definition according to the Czech Mining Authority:
- a bump is natural occurence of sudden disruption of
mountain massif which causes sudden sliding or
disembowlement of rocks to the underground. Its
effect is sudden and permanent deformation.
- This occurence may be accompanied by seismic and
sound effect
"Underground In The Cloud"
"Underground In The Cloud"
Anti-bump prevention
• System of activities aiming at recognition of
the pre-phase of bump
• Package of measures for prevention of bump
or reduction their aftermath
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BUMP PHENOMENON
• Mine excavation is not deformed but these
deformation can be measured be apparatus
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SHOWINGS of BUMPS
• Observable or measurable phenomena of
seismic activities of that we know that they
are connected with cumulation of stress in the
massif and they may be a portent of a bump
• It is based on our previous experience
Coal Mines with a Danger of
Bumps
• Coal mines where bumps have occured or may be
thraetened according to regional prognosis
• Regional Department of Mines categorize which
coal mines belong to the category:
• a/ coal mines with a danger of bump
• b/ coal mines without a danger of bump
• c/ in a coal mine with a danger of bump is
possible according to regional prognosis to
categorize a part of a rock masif to the group
„without of danger of bump
Prognosis of bumps
• Summary of activities which enable us to
determine the tendency of the rock masif to the
bump, determine the level of risk of bump in
planned, projected and running mine excavation
and properly choose the means of anti-bump
prevention
• Prognosis of showing of bumps is divided in:
•
- regional
•
- local
•
- current
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Regional prognosis
• Summary of activities which enable us to
determine the tendency of the rock masif
based on evaluation of natural conditions and
evaluation of bump occurence under similar
conditions
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Local prognosis
• Summary of activities enabaling us to
categorize mine excavation into levels of
bump risks during planning and projecting
• The result is categorisation of mine
excavations, more precisely their parts, into
1st, 2nd and 3rd level of bump risk
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Current Prognosis
• Summary of activities done in mine excavations to
label locations with risen stress, validation of
protected zone and possible control of the efficiency
of taken means of anti-bump prevention.
• These means are as follows: drilling tests, individual
observation, seismoacoustics and seizmology.
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Active Means of Anti-Bump Prevention
• Summary of activities leading to the lowering
of the bump risk
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PassiveMeans of Anti-Bump
Prevention
• Summary of activities, measures and
mechanisms leading to the lowering of the
bump risk
"Underground In The Cloud"
Active Means of Anti-bump
prevention:
• Proper space-time leading of mine excavations
• Rock blasting without breakup (OOTP) in a seam and
surrounding rocks
• Waterinfusion from surrounding rocks
• Overcoring
• Properly chosen technology during leading and
securing of mine excavations
"Underground In The Cloud"
"Underground In The Cloud"
The Reason for Rock Blasting without
Breakup is:
• Deformation of seam as a result of explosion
• Stress rearrangement to a further place from
mine excavation = behind protected
zone(area)
• Relieving of higher stress
Passive Means of Anti-bump
Prevention
• Chioce of a manner of a strength in gallery
sheeting
• Stabilisation of weakened parts rock masif by
grouting and anchoring
• Creating of protective caves or compensating
space
• Developing of bump – with an absence of people
• Rock blasting breakup
• Reduction of workers in endangered areas
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Passive Means of Anti-bump
Prevention
•
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•
•
•
Locking up of redudndant mine excavations
No workers in case of danger identification
Distant control of machines
The way of placing of devices in mine excavation
Protection of disconnecting of electronic device
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"Underground In The Cloud"
1st level of danger of bump is valid for:
• All mine excavation led out of seam
• Long mine excavations in a seam with a
thickness to 1.2 m with enlarging of
accompanying rocks
• Mine excavations in the seam without
prediction of bumps
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2nd level of danger of bump is valid
for:
• Mine excavations where we cannot exclude
the danger of bump
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3rd level of danger of bump is valid
for:
• Mine excavations where we can predict bump
• Mine excavations where a bump has occured
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• The amount of bumps is rather high, only
some bumps may destroy mine excavation
and kill miners
• It is impossible to avoid bumps even if mining
company founder try to predict them
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Děkuji za pozornost.
Ing. Viktor Pavelka