🔹 1. Introduction

Belt conveyors are one of the most efficient and widely used systems for transporting bulk materials in mines. They offer continuous, reliable, and cost-effective transportation compared to trucks or skip hoists. In mining, conveyors are used to move ore, coal, and overburden over long distances with minimal energy loss.

🔹 2. Major Components of Belt Conveyor

Component	Function
Belt	Acts as the carrying and pulling medium
Drive Unit	Provides motion through motor, gear reducer, and coupling
Pulleys	Head and tail pulleys drive and return the belt
Idlers	Support the belt and reduce friction
Take-up Device	Maintains tension and compensates for stretch
Feeder/Loading Device	Controls material flow onto the belt
Safety Devices	Prevent belt reversal or spillage

🔹 3. Types of Belt Conveyors

1. Flat Belt Conveyor
   
2. Trough Belt Conveyor
   
3. Pipe Conveyor
   
4. Steep Incline Conveyor
   
5. Overland Conveyor
   
6. Underground Belt Conveyor
   

🔹 4. Conveyor Holdbacks (Anti-runback           Devices)

Inclined conveyors require holdbacks or backstops to prevent reverse movement of the loaded belt during power failure.
Backstops are safety devices installed at the head pulley or low-speed shaft.

Types of Backstops:

• Ratchet and Pawl
  
• Differential Handbrake
  
• Overrunning Clutch (Roller and Sprag Type)
  

Best type: Overrunning clutch type – automatic engagement, no backlash, longer life.

🔹 5. Design Considerations

• Belt Speed: 1.5 – 6.0 m/s
  
• Capacity: Depends on belt width, speed, and material density
  
• Drive Power: Determined by length, lift, and load
  
• Inclination Angle: Usually <18° for bulk solids
  
• Tensioning: Screw, gravity, or hydraulic system
  

🧠 25 DGMS-Style MCQs – Belt Conveyors in Mining

1️⃣ Belt conveyors are mainly used for —

a) Vertical haulage
b) Horizontal or inclined transport of bulk materials
c) Crushing operation
d) Drilling in mines
e) Shaft sinking

✅ Answer: b) Horizontal or inclined transport of bulk materials

2️⃣ The main advantage of belt conveyors over trucks is —

a) Lower installation cost
b) Continuous operation and low running cost
c) Requires more manpower
d) Limited capacity
e) None of these
✅ Answer: b) Continuous operation and low running cost

3️⃣ The carrying medium in a belt conveyor is —a) Rope
b) Chain
c) Belt
d) Screw
e) Roller
✅ Answer: c) Belt

4️⃣ The device used to maintain tension in the belt is —

a) Tail pulley
b) Take-up pulley
c) Idler
d) Counterweight
e) Drive pulley
✅ Answer: b) Take-up pulley

5️⃣ The function of idlers in a conveyor is to —

a) Support the belt and material load
b) Increase belt tension
c) Reduce belt speed
d) Control discharge
e) Change belt direction
✅ Answer: a) Support the belt and material load

6️⃣ Which part of the conveyor provides motion to the belt?

a) Tail pulley
b) Drive pulley
c) Take-up device
d) Counterweight
e) Idler roller
✅ Answer: b) Drive pulley

7️⃣ Backstops or holdbacks are used to —

a) Prevent belt sag
b) Prevent belt reversal
c) Adjust belt speed
d) Control discharge rate
e) Maintain lubrication
✅ Answer: b) Prevent belt reversal

8️⃣ The most reliable type of backstop for conveyors is —

a) Ratchet and pawl
b) Differential handbrake
c) Overrunning clutch (sprag type)
d) Chain lock
e) Friction disc
✅ Answer: c) Overrunning clutch (sprag type)

9️⃣ Inclined conveyors require a backstop because —

a) They move materials upward
b) They operate faster
c) They are longer in length
d) They use multiple motors
e) They use smaller belts
✅ Answer: a) They move materials upward

🔟 The angle of inclination for most belt conveyors is —

a) <5°
b) <10°
c) <18°
d) <25°
e) <30°
✅ Answer: c) <18°

11️⃣ The working principle of a belt conveyor is based on —

a) Centrifugal force
b) Frictional drive
c) Electromagnetic force
d) Pneumatic force
e) Mechanical pressure
✅ Answer: b) Frictional drive

12️⃣ Which factor does NOT affect conveyor capacity?

a) Belt width
b) Belt speed
c) Material density
d) Belt color
e) Angle of inclination
✅ Answer: d) Belt color

13️⃣ Belt conveyors are preferred for —

a) Short-distance haulage
b) Long, continuous haulage
c) Vertical lifting
d) Manual operation
✅ Answer: b) Long, continuous haulage

14️⃣ The head pulley is located at —

a) Loading point
b) Discharge end
c) Midsection
d) Tail end
✅ Answer: b) Discharge end

15️⃣ The tail pulley is located at —

a) Discharge end
b) Loading point
c) Drive motor end
d) Gearbox end
✅ Answer: b) Loading point

16️⃣ The belt is supported along its length by —a) Rollers (idlers)
b) Steel plates
c) Chain links
d) Frames
✅ Answer: a) Rollers (idlers)

17️⃣ The tension in the belt is maintained by —

a) Gravity take-up
b) Friction
c) Magnetic brake
d) Hydraulic brake
✅ Answer: a) Gravity take-up

18️⃣ The capacity of a conveyor increases with —a) Decrease in speed
b) Increase in belt width and speed
c) Reduction in slope
d) Using smaller pulleys
✅ Answer: b) Increase in belt width and speed

19️⃣ The power required to drive a belt conveyor depends on —

a) Belt length
b) Lift height
c) Material load
d) All of the above
✅ Answer: d) All of the above

20️⃣ The function of a take-up pulley is to —

a) Prevent slippage and maintain tension
b) Reduce belt width
c) Increase belt speed
d) Maintain belt direction
✅ Answer: a) Prevent slippage and maintain tension
21️⃣ Which type of belt is most commonly used in mines?

a) Fabric belt
b) Steel cord belt
c) Wire mesh belt
d) Rubber belt
e) PVC belt
✅ Answer: d) Rubber belt

22️⃣ Conveyor speed is generally expressed in —

a) m/s
b) km/hr
c) rpm
d) ft/min
✅ Answer: a) m/s

23️⃣ Conveyor power is calculated in —

a) Watts
b) kW
c) HP
d) All of the above
✅ Answer: b) kW

24️⃣ Which component helps in loading control on the belt?

a) Feeder device
b) Take-up pulley
c) Counterweight
d) Backstop
✅ Answer: a) Feeder device

25️⃣ DGMS classifies belt conveyors under —

a) Mine safety devices
b) Material handling equipment
c) Drilling machinery
d) Hoisting systems
✅ Answer: b) Material handling equipment

🧾 Quick Recap

• Purpose: Continuous bulk transport
  
• Key Parts: Belt, drive pulley, idlers, backstop
  
• Angle: Usually <18°
  
• Design Factors: Belt width, speed, and load
  
• DGMS Focus Areas: Holdbacks, torque, and safety
  

                       🔚 Conclusion

Belt conveyors are indispensable in modern mining for efficient and safe material transport. With minimal maintenance, low energy costs, and essential safety components like holdbacks, they remain the most reliable material-handling system. DGMS exams frequently feature MCQs on design parameters, backstops, and conveyor safety.

🚀  Preparing for DGMS Mechanical or Overman exams?
📘 Read next: “Belt Conveyor Holdbacks – Design, Torque & Selection | DGMS Mechanical Notes.”
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