Power shovel

Power shovel is a bucket equipped constuction equipment used for excavating and transporting all classes of earth (except solicd rocks without prior loosening) to nearby trucks or other hauling equipments.

1. Power Shovel Submitted by : Arpit Saini (CO13214) Ashi Gupta ( CO13215)

2. Definition Power shovel  (also  stripping shovel  or  front shovel  or  electric mining shovel ) is a construction equipment whose purpose is to excavate the earth and load it into the trucks or other pull equipment waiting nearby.

3. Types Type of power shovel is described by its mounting - If it is mounted on crawler track, it is called crawler-mounted power shovel. If it is mounted on rubber tyred wheels it is referred as wheel-mounted power shovel .

4. Wheel mounted power shovel Crawler mounted power shovel

5. Size of power shovel Size of power shovel is indicated by the size of dipper generally expressed in cubic meters. They are available in size 3/8, ½, ¾, 1, 1 ¼, 1 ½, 2 and 2 ½ cubic meter which come under the category of standard power shovels. Modern bucket (dipper) capacity ranges from 8 cubic metre to 80 cubic metre .

6. Basic parts The mounting (crawler track or rubber tyred wheel) Cab Boom Dipper stick Dipper Hoist line           

7. Operation The shovel operates using several main motions: hoist - pulling the bucket up through the bank (i.e. the bank of material being dug) crowd - moving the dipper handle out or in to control the depth of cut and when positioning to dump swing - rotating the shovel between digging and dumping propel - moving the shovel unit to different locations or dig positions

8. Working Support cable Angle of swing Hoist cable Boom Dipper stick cab

9. Selection of type and size Best type is decided after considering various techno-economic factors : a)Job location Numerous Small jobs – Rubber tyred Large job – Crawler mounted b)Type of footing Soft and muddy soil – Crawler mounted .

10. For selecting the best size of the shovel for the given job, the following factors must be examined : a)  The cost of per cubic meter of output : Minimum cost per cubic metre of output. Size of job Cost of transporting Depreciation rate Downtime cost – Time lost during repair & adjustments Cost of wage – Less for large shovel Cost of drilling , blasting, excavating- Less expenditure for large size shovel b)  The job/site conditions   For high lifts to dump - long boom of a large shovel. For excavating blasted rocks, hard and tough bed of soil - large size dipper. High hourly output - large shovel Size of hauling unit determines size of shovel.

11. OPTIMUM  DEPTH OF CUT The optimum depth of cut is that depth which produces the greatest output and at which the dipper comes up with full load without excessive downward pressure and tension. This depth varies with the type of the soil and the size of the dipper.

12. OUTPUT OF POWER SHOVEL Output of shovel = bank measure capacity of dipper x 3600/cycle time in second (m3/hr) In general cases, Output of shovel =  Loose volume of dipper /   (1 + Swell fraction)   x  Actual time in seconds per hour / Cycle time in seconds x  efficiency Expressed in cubic meter/hr            

13. Factors affecting the output Class of material According to Power Crane and shovel association, USA -   Moist loam or light sandy clay > Sand and gravel > good common earth > Hard , tough clay > Wet, sticky clay > Poorly blasted rock Depth of cut Depth shallow – output reduced Depth greater – output increased Angle of swing Horizontal angle (ex-pressed in degrees) between the position of the dipper when it is excavating and the position when it is discharging the load. The output of shovel is inversely proportion of the cycle time and thus to the angle of swing. Job conditions Job conditions may be classified as excellent, good, fair and poor depending upon the situations of work site and climatic condition

14. e) Management conditions Excellent management conditions yield maximum output while poor one may yield the minimum. f) Size of hauling units Small size of hauling unit – small shovel size g) Skill of Operator Skillful operator – output increases h) Physical condition of the shovel Good condition – output increases Bad shape – subjected to wear and tear

15. Applications Suitable for dragging softer material. Can remove big size boulders with prior loosening. It is used in various types of jobs such as digging in gravel banks, clay pits, digging cuts in road works, road side berms etc. It is very useful for excavating trenches . It is mostly used in the excavation for canals and depositing on the embankment without hauling units . Used for excavation and removal of overburden .

16. Shovel digging overburden

17. Thank you