Construction Chapter 13: Aggregate Production

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What is the unit weight of the crushed stone in lb/cf?

95 lb/cf

120 lb/cf

110 lb/cf

102 lb/cf (correct)

What is the permissible efficiency of the screen?

85%

80%

95%

90% (correct)

What is the width of the screening unit in feet?

4.5 ft

3 ft

3.5 ft (correct)

4 ft

What is the closed setting of the jaw crusher in inches?

5 in. Signup and view all the answers

What is the size range of the crushed stone output from the jaw crusher?

5 to 4 in. Signup and view all the answers

How many decks will the horizontal vibrating screen have?

3 decks Signup and view all the answers

What is the weight of the crushed stone in lb/cf according to the second part of the text?

110 lb/cf Signup and view all the answers

What is the name of the association that provides support in operating productivity improvements, engineering research, safety and health, environmental concerns, and technical issues?

NSSGA Signup and view all the answers

What factor does not directly influence the capacity of a crusher?

Amount of explosive used in drilling Signup and view all the answers

Which process involves separating materials based on particle size ranges?

Sizing Signup and view all the answers

What equipment is used to load the stone that is to be crushed?

Shovel, excavator or loader Signup and view all the answers

What is the primary function of washing in aggregate production?

Eliminating undesirable materials Signup and view all the answers

Which component of a jaw crusher is movable?

Inclined jaw Signup and view all the answers

What is the purpose of matching the capacity of the shovel or loader to the crushing plant?

Ensure economic production Signup and view all the answers

In aggregate production, what chapter primarily discusses transport?

Chapter 9 and 10 Signup and view all the answers

Which process follows after the stone is crushed and screened?

Storage and transport Signup and view all the answers

What is the recommended factor of safety for selecting a screen with calculated capacity greater than the required capacity?

10 to 25% Signup and view all the answers

What is the minimum screen size recommended for screening 120 tph of dry crushed stone?

4- by 10-ft Signup and view all the answers

What is the weight per cubic foot of the dry crushed stone being screened?

100 lb/cf Signup and view all the answers

What percentage of the aggregate is smaller than the in.in size?

30% Signup and view all the answers

What type of machine is a screw-type classifier used for?

Producing specification sand Signup and view all the answers

Where is the motor located in the single screw classifier shown in Figure 13.22?

At the discharge end Signup and view all the answers

What activates the discharge valve in sand classifiers to enable material flow into the splitter box?

A paddle Signup and view all the answers

In sand classifiers, which size sand particles settle last in the tank?

Fine Signup and view all the answers

What is the maximum output of the roll crusher in tons per hour for material less than 1 inch?

45 tons per hour Signup and view all the answers

If 12% of the stone from the quarry is smaller than 1 inch and removed before sending it to the jaw crusher, how does this affect the process?

It ensures that only larger stones are processed by the jaw crusher Signup and view all the answers

What is the correct screen efficiency to use when determining the minimum-size screen required to handle the crusher output with a permissible efficiency of 85%?

85% Signup and view all the answers

For the output of a 47- by 34-inch crusher and an opening of 3 inches, what is the minimum size screen required to handle this output?

47.1 sf Signup and view all the answers

What is the average number of fatalities per year in the mining industry?

40 to 50 Signup and view all the answers

What is the permissible efficiency when using a 90% efficient vibrating screen for the output from a 40- by 30-in. jaw crusher?

90% Signup and view all the answers

Considering the 40- by 30-inch jaw crusher details, what is the unit weight of crushed stone?

106 lb/cf Signup and view all the answers

What is one of the primary causes of mining fatalities?

Entanglement with powered haulage equipment Signup and view all the answers

Why is it crucial not to remove guards, covers, or shields when the equipment is running?

It poses a safety risk Signup and view all the answers

Given a screen width of 4 feet, how should the length of the screen be chosen for integer dimensions?

Lengths should be in integer dimensions of feet Signup and view all the answers

Which administration regulates the safe operation of aggregate production plants in the U.S.?

Mine Safety and Health Administration (MSHA) Signup and view all the answers

What is the percentage requirement for the aggregate to pass through a 1.5 in. screen according to the specifications?

100% Signup and view all the answers

What should always be done before performing maintenance to prevent unexpected motion?

Establish a positive lockout of the power source Signup and view all the answers

Which document details the safety risks of removing protective covers and guards from rock processing equipment?

MSHA accident reports Signup and view all the answers

Why is it essential to wear hard hats in aggregate production facilities?

To guard against contact with overhead equipment components Signup and view all the answers

What should be done before beginning the operation of any crushing equipment or conveyor?

Sound an audible warning alarm Signup and view all the answers