Opencast mine Entry system

• When a ore body is worked an approach road is always required to reach the ore body. Such approach road is known as entry system

Types of entry system1.Single entry systema. Single entry system at on endb. Single central entry system 2. Double entry systema. Two end entrance with single working faceb. Two end entrance with two working facec. Two end entrance use once at a time3.Triple entry system4.Spiral entry system5.Shunt back or switch back entry system

Single entry system

Located at one side of the pit Suitability conditionsa. Short pit length up to 800-1000m b. Low to medium productionc. Small pittypesa. Single entry system at on endb. Single central entry system • If the length of the pit is more than 1000 m Single central entry system is preferred since

it minimizes the distance of haul of the mineral with in pit and hence cost of transportation• a central entry virtually divides the pit into two blocks which can be worked alternately

using a single set of machines or simultaneously on either side of the entry with two sets of machines

• Advantages of single entry system1. Maintenance of single road only2. Easy to maintain3. Easy to check control of vehicle movements4. Maintenance of supply of vehicle for overburden and ore can be

regulated• Disadvantages1. High rate of wear and tear of road2. Regular maintenance of road3. Incase of break down of single vehicle all transportation system will

come to halt4. The proper account of vehicle can not be maintained5. High traffic density

Double entry system

Located at both side of the pit Suitability conditionsa. pit length up to 1500-2000m b. Medium to high productionc. Medium size pittypes1. Two end entrance with single working face2. Two end entrance with two working face3. Two end entrance use once at a time

• Advantages of double entry system1. Limited number of vehicle on any one rout has less wear and tear of

road2. Less interference of vehicle and vehicle density3. Ore and overburden can handle separately4. Incase of break down of single vehicle all transportation system will

not come to halt5. The perfect record of vehicle movement can be record6. Less road maintenance7. Longer life of route• Disadvantages1. High cost of maintenance2. Blockage of ore below the route

Triple entry system

Located one at both side and one in centre of the pit , multiple faces can be worked Simultaneously worked with this system of transportation of mineral Suitability conditionsa. pit length more than 2000m b. Very high productionc. Large size size pit

Spiral entry systemSuitability conditionsa. Ore body on the top of hillb. Deep pit

• Advantages of spiral entry system1. The movement of vehicle is easy2. The vehicle can carry more load3. The movement of vehicle is well controlled by brakes4. The speed of movement is comparatively high5. Maintenance of single road only6. Easy to maintain7. Easy to check control of vehicle movements8. Maintenance of supply of vehicle for overburden and ore can be regulated• Disadvantages1. Since the haul road runs along the periphery of the pit mining has to start from the pit

boundary and proceed downwards one bench at a time, leads to heavy investment in removing overburden

2. High rate of wear and tear of road3. Regular maintenance of road4. Incase of break down of single vehicle all transportation system will come to halt5. The proper account of vehicle can not be maintained6. High traffic density7. Longer haul length8. Large width of road9. Reduction of speed at turning

Shunt back or switch back entry system• in still deeper pits It may not be possible to provide a separate track or road to eachbench from the main pit approach , since this may require too long a pit approach under such

conditions the switch back system of track layout may be adoptedHere the whole train has to shunt back and front on each bench In order to get down to the bottom bench

Numbers of entry systems

Depends on 1. Length of the pit along strike2. Mode of transportation3. Desired production,4. The requirement of separate routs for mineral and overburden transport,5. Distance of haul, and cost of haulage6. System of handling of overburden soil, rock and also handling of mineral,7. Working of number of faces simultaneously,8. Overall economy,

Location of entry system

1. Surface topography and nature of ground2. Shape of mine3. Length of mine along the strike4. System of waste disposal and disposing site,5. The required gradient of haulage system,6. Depth of working7. System of mineral and overburden handling,8. Requirement of production,9. Simultaneous working of number of faces in the mineral and overburden

benches,10. Location of processing 11. No of working face plant and dump12. Space avilable13. Overall economy.