KNOWLEDGE MANAGEMENT COMMUNITY,JAGANNATH AREA,MCL

BLASTING – It is technique in which , solid rock mass is brought in to small by using explosives . Explosives- It is a solid or liquid substance or a mixture of chemical substance which is converted instantaneously in to Large volume of gases at high temperature and pressure when subjected to combustion or detonation . chemical energy is converted in  to mechanical energy which is used to break the rock masses in to small pieces. Detonation-  it is a process of giving sufficient violent shock to the explosives or it is a process of propagation of shock wave through an explosives. Types of explosives Low explosives & high Explosives • Strength-Amount of energy by an explosive during blasting. • Velocity of Detonation-Rate at which detonation wave passes through a column of Explosive . More the intimate contact between oxidizer and fuel , higher will be the VOD. • Density- High density explosive required for blasting in hard rock in tunneling in hard groun

PIT DESIGN HEIGHT AND WIDTH OF BENCHES IN OPENCAST MINE 1.In A lluvial, soil, morum , gravel, clay, debris ( soft over burden), the sides shall be sloped at an angle Of safety not exceeding 45 degree from the horizontal or at an angle Regional inspector permit. Kept benched at ht. not exceeding 1.5 m and width shall not be less than ht. 2. In coal sides shall be sloped at an angle of safet not exceeding 45 degree from the horizontal or the sides shall be kept benched not exceeding 3 mtr . In ht.. IN MECHANISED MINE 1.A.Ht.of bench shall not exceed the maximum reach of m/c used for digging, excavation and removal.  incase of uniformly soft rock the regional inspector may permit the extension of the ht. up to 3 mt. above the digging ht. of the m/c. B. Width of any bench shall not be less than § Width of any m/c plying on the bench plus 2 mtr .       Or § If the dumper is plying on the bench 3 times the width of the dumper.       Or   § Tw