In most civil engineering in mining applications of blasting, a type of explosive called ANFO is used.  ANFO is comprised of 94 % Ammonium Nitrate and 6 % fuel oil.  When blasting a rock section in mining, multiple holes usually of about 5 centimeters in diameter are drilled in a grid series, called a blast pattern.  The depth and spacing in between these holes is determined from the powder factor and from the length that is desired to be penetrated.  Setting up a blast pattern allows a section of the material with roughly known dimensions to be removed. [5]

A specialist charges a hole with ANFO
 
© Timo Halén

Diagram showing some of the theory in setting up a blast pattern

© geodrillinginternational.com

A large blast pattern in open pit mining

© constructionphotography.com

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