Rock Fragmentation — Summer 2022

Draw the line diagram or sketch of components of drilling equipment & name the components.

Explain delay detonators and its advantages with neat sketch

Aproject in granite rock will have an average bench height of 25 feet. An explosive having a specific gravity of 1.2 has been proposed. Adrill machine can easily drill 3.0 inch diameter of holes. Assume diameter of explosive will be 2.6 inch and delay blasting technique will be used. Develop a blast design for the project. Take specific gravity of granite is 2.9.

Differentiate between low explosive & high explosive with suitable examples.

Discuss the properties of explosive in detail.

What is mechanics of drilling? Explain the mechanism of rock breakage by percussive drilling with neat sketch.

Write a short note on stoper and drifter. Also discuss the construction and operation of wagon drill machine.

Make a tree diagram of classification of drilling methods. Also write the factors affecting the selection of drill machine.

Discuss the principle and operation of “jack hammer” drill machine used in underground coal mining.

Define powder factor with its importance in blasting? Calculate the powder factor (kg/m3 ) from below data :- (i) Bench Height – 12 m (ii) Hole Dia. – 165 mm and amount of explosive loaded in blast hole = 11.5 kg/m. Assume the parameters if required.

Compare rotary drilling method with percussive drilling method.

Discuss the blast design pattern using in surface mine with neat sketch.

Why control blasting methods are used in mines? Explain any two method of control blasting in detail.

Explain the importance of permitted explosive in underground coal mines. Also write its type.

What is VOD and how it is determined?

Calculate the powder factor in tonne/kg from below data:  Bench height including subgrade drilling = 10 m  Burden = 4 m  Spacing = 5 m  Subgrade drilling = 0.5 m  Stemming length = 3 m1 If the diameter of the hole is 200 mm and density of explosive and rock is 0.9 tonne/m3 and 2 tonne/m3 respectively.

Explain the application and importance of high speed video camera in mining.

Why drillability is important? Also write the factors affecting the drillability of rock.

Discuss the causes and Impact of ground vibration and air blast on the neighboring structures and communities. Also explain its mittigative measures.

What are the advantages of using image analysis technique for fragmentation analysis of a muckpile?

What do you mean by penetration rate and how it is determined in the mine? Explain with one example.

What is secondary blasting? Explain its types in detail.

Differentiate between the term slurry and emulsion explosive.

Relative weight strength of an unknown explosive is 1.5 times of ANFO in Jules/gm. Absolute strength of TNT is 4000 Jules/gm. TNT has relative bulk strength of 3 times of the ANFO in Jules/cm3. If the specific gravity or density of ANFO, TNT and unknown explosive 0.9, 1.5 and 1.2 respectively. Determine the absolute strength of unknown explosive in Jules/gm and Jules/cm3.

Discuss the blast design pattern using in underground mine with neat sketch. .