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TitleExplosives and Blasting in UG Coal Mines
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Table of Contents
                            Explosives and Blasting in Underground Coal Mines
	Permitted Explosives
	Non Permitted Explosives
Document Text Contents
Page 7

Explosives & Blasting in Underground Coal Mines
Author: Partha Das Sharma (E.mail: [email protected])


advance is limited. For deep pulls burden should be reduced by providing steeply inclined hole
at the centre, known as 'Stab Hole' or by giving another shallow wedge cut known as 'Baby Cut'.
This relieving hole should be fired prior to the main wedge cut pattern. Following some of the
examples given :

No. of Holes = 14+1stab hole = 15 (Total), size of gallery = 4.3m x 2.4m

Delay Number Charge (Cartridge) Explosive (gm ) Explosives
Charged (gm)

0 1 3 555 555
1 2 3 555 x 2 1110
2 2 3 555 x 2 1110
3 4 2 370 x 4 1480
4 4 2 370 x 4 1480
5 2 2 370 x 2 740

Total Charge :- 6.5 kg, Av. Pull :- 1.35m to 1.45m
Blasting Ratio (PF) :- Av. 2.6 t/kg Detonator Factor :- 1.1 to 1.2 t

In Fan Cut Pattern, the initial opening is created by firing a hole drilled at an acute angle to the
face. The inclination generally varies from 30 to 60 degree. The inclination of subsequent hole
is gradually reduced. This pattern suitable for medium hard to hard coal seams. Some
illustrations are given below :

Page 12

Explosives & Blasting in Underground Coal Mines
Author: Partha Das Sharma (E.mail: [email protected])


Author’s Bio-data: Partha Das Sharma is Graduate (B.Tech – Hons.) in Mining Engineering
from IIT, Kharagpur, India (1979) and was associated with number of mining and explosives
organizations, namely MOIL, BALCO, Century Cement, Anil Chemicals, VBC Industries, Mah.
Explosives etc., before joining the present organization, Solar Group of Explosives Industries at
Nagpur (India), few years ago.

Author has presented number of technical papers in many of the seminars and journals on varied
topics like Overburden side casting by blasting, Blast induced Ground Vibration and its control,
Tunnel blasting, Drilling & blasting in metalliferous underground mines, Controlled blasting
techniques, Development of Non-primary explosive detonators (NPED), Signature hole blast
analysis with Electronic detonator etc.

Currently, author has following useful blogs on Web:


Author can be contacted at E-mail: [email protected], [email protected],
Disclaimer: Views expressed in the article are solely of the author’s own and do not necessarily
belong to any of the Company.

mailto:[email protected]
mailto:[email protected]

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