Table of Contents
How is blasting carried out in mining?
Blasting in mining is a chemical and physical process that occurs through the firing of explosives. It breaks mineral-bearing materials. These materials can be coal, ore and mineral stone. Blasting fragments materials, splits off rock blocks, and demolishes existing structures.
What explosives are used in coal mining?
The base explosive used in mining is called Ammonium Nitrate Fuel Oil (ANFO). Oxides of Nitrogen can be inadvertently generated as fume by the incomplete detonation of explosives during a blast.
What is the first step of blasting?
The typical cycle of excavation by blasting is performed in the following steps: Drilling blast holes and loading them with explosives. Detonating the blast, followed by ventilation to remove blast fumes. Removal of the blasted rock (mucking).
Which blasting technique is used for controlled throw of overburden?
Blast casting is a high-efficiency technique applied in surface mines for overburden removal and results in stripping cost savings.
What happens during blasting?
blasting, process of reducing a solid body, such as rock, to fragments by using an explosive. Conventional blasting operations include (1) drilling holes, (2) placing a charge and detonator in each hole, (3) detonating the charge, and (4) clearing away the broken material.
What is the required before blasting?
A successful blast has to meet two basic conditions: (1) the explosive in each blasthole is completely detonated, and (2) detonator position, charge length, initiation plan, quantity of detonators in each borehole, delay time, and so on are correct, regardless of the types of detonators.
How many types of blasting are there in mining?
The six controlled blasting techniques that will be discussed are (1) line drilling, (2) trim blasting, (3) buffer blasting, (4) smooth wall blasting, (5) air decking, and (6) presplitting. There are a number of uncommonly used controlled blasting techniques.
What is misfire in blasting?
A misfire results when explosives fail to detonate as planned during a mine blast. Accidental detonation of misfires is a frequent cause of personal injury, equipment damage, and lost production.
What is emulsion in blasting?
Ammonium Nitrate Emulsion (also called EP or Emulsion Phase) is ammonium nitrate dissolved in water and suspended in oil. It is an oxidising agent used to manufacture a range of bulk blasting agents. The oil surface gives emulsion based products improved water resistance.
What is blast pattern?
The array of drilled holes on the surface or underground to be loaded and detonated in sequence; a pattern is indicated by the distance between holes in a row (spacing) and between rows (burden).
What is the blasting pattern?
What is a blast pattern? It is the geometry of the drill holes laid out of a bench or the real pattern after drilling at the bottom of a bench. Also, the geometry of the drill holes at the face of a drift or tunnel including the burden and the spacing distance and their relationship to each other.