EFFECT OF DECKING ON BLASTING PERFORMANCE IN LIMESTONE MINE
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Date
2019-04-30
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MPUT, UDAIPUR
Abstract
Blasting being the cheapest mean of rock breakage continue to be the most prevalent
method of rock fragmentation in the mining. The prime objective of blasting in a mine is to
get desired fragmentation with minimum cost and minimum environment nuisance. Blast
performance is the key prime mover and need to be monitor on continue basis. Site specific
and customised blast designed parameters are the need to suit the dynamic of geo mining &
physio-mechanic condition of rock.
Deck blasting improves charge distribution, reduction in explosive usage and optimizing
other blast parameters. The mechanism by which the explosive energy is transferred to the
surrounding rock mass is changed in deck blasting. It allows the explosive energy to act
repeatedly in pulses on the surrounding rock mass rather than instantly as in the case of
concentrated charge blasting.
The present research study has been conducted in the captive limestone of wonder cement
where major problem of ground vibration and fragmentation are witnessed. To address the
problem 10 base line blasts and 08 experimental blasts were conducted for research work.
During all base line blasts and experimental blasts, the ground vibration, air overpressure
and fragment size parameters are being monitored and analysed using Blastware, Fraglyst,
Pattern analyser software. Powder factor and cost per tonne are also evaluated.
The maximum ground vibration observed in base line blasts was 9.33 mm/s while in deck
experimental blasts it was 5.96 mm/s, measured at 150 m distance back side of blasts. The
Air overpressure maximum observed was 128.1 dB in base line blasts and 98.8 dB in deck
experimental blasts. The mean fragment values (K50) in base line blasts varies between 0.33
m to 0.59 m while in experimental blasts, it varies between 0.26 m to 0.30 m. In the base
line blasts, percentage of oversized fragments varies from 7 % to 26 % while in
experimental blasts it varies from 5 % to 7 %, and considered normal rate of oversized
boulders percentage in any blasting. Blasting cost is also reduced by 5.95% & 11.42% in
deck blasting. Powder factor increased in deck length 0.8 m as compared to 0.5 m length.
But air overpressure increased and shovels efficiency declined in deck length 0.8 m blasts as
compared to 0.5 m deck length blasts. Optimum blast designed is being suggested for study
area.
Description
EFFECT OF DECKING ON BLASTING PERFORMANCE IN LIMESTONE MINE
Keywords
Citation
MATARIYA S.J. And Jain S.C