Surface miner and its performance
- 3. • Introduction • Principle design of surface miner. • Working principle of Surface miner. • Performance of Surface miner. • Summary.
- 4. ☻The conventional method of mining includes – Drilling, Blasting, and Face loading. ☻ Even enough technology development took place to take care of fly rock, still there is a problems. And the second foremost is cost effective mining and also quality control. ☻ To overcome the above problems, a series of research and development led to the development of new technology known as Blast free mining by SURFACE MINER.
- 5. These jobs are no longer required: Cleaning, levelling and bolder splitting Surface Miners Drilling Blasting Loading Crushing
- 6. ☻A significant improvement can be achieved in the following area- > Produce clean and high quality material. > Deposit can be exploited fully. > Reduction in transportation cost and production process. > Environmental friendly mining. ☻It also takes care of both safety part and economics in mining Some direct benefits are – 1. Mining with out blasting, therefore no need for drilling. 2. Insitu crushing & sizing before conveying on to the truck is possible.
- 7. 3. Surface miners have a unique conveying system by which the mined material is directly loaded onto the truck / dumper. 4. The haul road preparation and maintenance in deposit are reduced. Even some times its not required. This system has special advantage of selective mining Less coal loss and dilution. Improved coal recovery especially in areas sensitive to blasting. Less stress and strain on trucks due to minimum impact of the excavated material. Primary crushing and fragmentation of coal reduces the capacity requirements for coal washing / preparation plants.
- 9. The surface miner mainly consists of 5 units: 1. Mainframe: It consists of operators cabin, supporting frames, Boom counter weight, Slewing ring etc. 2. Conveying Unit: It consists of two stage conveyors, one carries the material from the cutting drum and discharges on the boom conveyor. This conveyor in turn conveys it on to the trucks. 3. Drive Unit: It consists of a diesel operated engine whose power is transmitted to the cutting drum via robustic belts drive. And it consists of hydraulic system to operate other units. 4. Crawler Unit: Based on the design it may be single pair crawler or two pair crawler.
- 11. Central Cutting Drum is driven mechanically by a diesel engine through belt drive
- 12. Cabin with all the controls Crawler Tracks
- 13. ☻The most important parameter is the cutting tool. ☻The selection of right cutting tool is essential for good cutting performance & high life, since, it constitute a major portion of operation cost of the machine. ☻The cutting depth can be regulated by automatic leveling system mounted on the machine, the pre-selected cutting depth is main -tained either automatically or manually. 5. Cutting Unit:
- 14. The milling processes used by surface miners are of two types: Up-milling: In this process, the milling drum rotates in the anti-clockwise direction when seen from right-side, of the direction of advance of the machine. During up-milling process, the milling drum, while cutting takes benefit of the structural properties of the rock, like lamination, inherent cracks and fractures, sedimentation, cleavage, etc. machines of companies like Wirtgen, Bitelli, L&T, use this process. This process increases the production of the machine as it uses the power developed by the engine is used in a more efficient way.
- 15. Down-milling: In this process, the milling drum rotates in the clockwise direction when seen from right side, of the direction of advance of the machine. Down milling is used in soft to medium hard material.
- 16. A diagram showing point of attack by Picks
- 17. Model Drum Width Cutting Depth(max.) No. of Picks 2100SM 2000mm 300mm 76 2200SM 2100mm 350mm 76 2200SM/3800 3800mm 250mm 200 SF202M 2000mm 200mm 84 KSM304 3000mm 400mm 105 KSM223 2200mm 300mm 76 TABLE SHOWING NUMBER OF PICKS IN DIFFERENT SURFACE MINERS
- 18. Belt Drive for Milling Drum: diagram
- 19. Picks: Some of the picks used in the surface miners are: Smaller diameter of tungsten carbide: 1. Low lifetime. 2. Good penetration. 3. High cutting. 4. Coarse gradation. Large diameter tungsten carbide: 1. Long time. 2. Poor penetration. 3. Low cutting performance. 4. Fine gradation.
- 20. Tool holders:
- 21. 1. Machine with front boom cutting drum. ☻In these type of machines cutter drum fitted with picks is mounted on a Boom, like road headers. Due to longer boom the cutting force of the machine is limited. BASED ON THE CUTTING PRINCIPLE AND POSITION OF THE DRUM, THE SURFACE MINER IS CLASSIFIED IN THREE TYPES.
- 22. 2. Machine with front cutting wheel ☻In this types of m/c, several bucket wheels are arranged in tandem & cutter picks are fitted on lip of each bucket to form the cutting drum, which is positioned in front of the m/c, just like BWE. ☻The m/c can exert huge force in cutting both hard coal and rock as the bucket wheel drum is close to the m/c and the reaction of cutting force is directly transferred to the ground through a hydraulically loaded dozer blade behind the bucket wheels.
- 23. 3.Machine with middle drum configuration ☻In these type of machines the cutting drum is positioned below the machine in between the front and the rear crawlers, cutting picks are fitted on a drum and having the depth of cut 500 to 600 mm BASED ON THE CUTTING PRINCIPLE AND POSITION OF THE DRUM, THE SURFACE MINER IS CLASSIFIED IN THREE TYPES.
- 25. Working Principle of Surface miner. ☻The surface miner is crawler-mounted machine having a cutting drum located between two sets of crawlers and positioned at the center of the machine. ☻The drum is lowered and raised by hydraulic system with powerful hydraulic motors thereby varying the depth of cut ☻The material cut is loaded onto the primary and secondary discharge conveyors for loading the same on to the loading / transporting equipment. ☻The rear crawler travel at lower level than the front crawlers to adjust to the required depth.
- 26. Precise cutting depth Clean, level and stable surface Continuous cutting Crushed aggregate Direct loading Cut, crush, and load in a single operation with one machine
- 27. Method of working MINING METHODS • Wide bench method • Block mining method • Stepped cut method Based on mode of travel • Empty travel method. • Turn back method. • Continuous mining method. Based on loading: Direct truck loading Indirect loading
- 28. 1231618 41424 102127 COAL SEAM OB SPOIL STEPPED CUT METHOD 6 12 79 1315 19 22 25 1231921 41424 71827 COAL SEAM OB SPOIL BLOCK MINING METHOD 6 9 1012 1315 16 22 25 12379 101418 192427 COAL SEAM OB SPOIL WIDE BENCH METHOD
- 29. Empty travel method ☻In this method the machine starts cutting operation from one end of the pit. After completion of the one full cut the cutting drum is raised & it moves back to the starting end without turning. ☻It travels empty while it moves backward and after reaching the starting point the machine gets ready for the fresh cut. ☻This method is applicable were the operating length is less than 200 meters.
- 30. Empty travel method Production travel Empty travel
- 31. Turn back method In this method, after completing the cut, the drum is raised and the m/c turn for the fresh cut which is adjacent to the previous cut. It is applicable where the length of face is >200m.
- 32. Continuous mining method Here, the machine moves with cutting the material and while approaching the pit end, the m/c turns with gentle angle without raising the drum.
- 33. BASED ON LOADING LOADING OPTIONS DIRECT TRUCK LOADING INDIRECT LOADING WINDROW SIDE CASTFRONT LOADING REAR LOADING
- 36. SIDE CAST
- 37. COMPARISON OF LOADING METHODS ADVANTAGES DISADVANTAGES Direct loading No re-handling of material required Where water percolation is more, this system of loading will give greater advantages. Larger working area required for truck Production affected by truck exchange Belt wear Side cast Blending of materials in the mine Stockpile of material in the mine No waiting for trucks Restricted to 3-5 cuts Belt wear Material has to be re-handled Material prone to absorb water when lying on ground Windrow No waiting for trucks No belt wear Higher production rates than conveyor loading Coarser material Better selectivity on steep inclined seams Larger working area required Material has to be re-handled Material prone to absorb water when lying on ground
- 38. Following are the possible uses of surface miners:- •Uses in mining sector: High purity of useful mineral, high cutting performance, low price per tone. 1.Selective mining from thin seams of useful mineral. 2.Mining rock without blasting. 3.Producing small particle sizes during mining process. •Uses in earth moving and construction: Production of precise, stable and defined profiles in rock. 1.Production of stable embankments. 2.Production of defined surfaces. 3.Production and rehabilitation of traffic routes. Main applications of surface miners: •Selective Mining : one of the most important characteristics of the surface miner is their ability to work highly selective. Thin distributed seams for example, can be mined precisely and economically. Advantages: 1.Enhanced ROM quality. 2.Improved exploitation of deposits. 3.Reduced stripping ratio. 4.Reduced processing after mining required.
- 39. •Material exploitation and crushing without blasting: Since there is no drilling and blasting problems of vibrations and fly rock are avoided. Blast free exploitation also ensures reduced noise and dust development. Primary crushing stage can be omitted in surface mining technology. Advantages: •Low investment costs in comparison to the range of equipment necessary for conventional mining. •Low operating cost due to less equipment and less personnel. •Several working steps are realized by only one machine, leading to easier co-ordination and process planning, dispatching and maintenance. •Improved exploitation of deposit. •Improved safety.
- 41. Performance of surface Miner Factors affecting the performance of surface miner Geological factors ☻Uniaxial Compressive strength ☻Abrasivity ☻Structure of the rock. ☻Binding material ☻Number of joints ☻RMR properties Machine Factors ☻Engine rating/power ☻Width and diameter of cutting drum ☻Traveling speed of the machine ☻RPM of the drum ☻Cutting depth ☻Pick design ☻Loading option
- 42. • Cuttability of rock which depends on its: Uni-axial compressive strength & tensile strength, Abrasivity & Structure ( number and distance of fractures) – depends on the formation to be cut • Cutting depth & Travel Speed of the Surface Miner while Cutting – depends on machine design • Area available for operation Larger the area, higher the productivity– depends on size of mine & mine planning Key factors to productivity
- 43. Effect of field length on productivity Larger the cutting length, higher the productivity
- 44. Abrasivity It has a direct correlation with number of picks consumed during the operation. Structure of the rock It is easy to cut with surface miner in highly jointed and fractured strata. Binding material It has a relation with pick consumption Uniaxial Compressive strength In general surface miners are capable of cutting rocks of hardness b/w 10-80 MPa. Under certain circumstances (E.g. Highly fractured material) even harder material can be cut economically.
- 45. Speed of cutting by SM2200 in different strata 17.03 18.83 19.32 24.13 0 5 10 15 20 25 30 shale coaly shale coal soft coal speed(m/min)
- 46. Depth of cut by SM2200 in different strata 0.183 0.171 0.168 0.202 0 0.05 0.1 0.15 0.2 0.25 shale coaly shale coal soft coal Depthofcut(m)
- 47. Production rate by SM2200 in different strata 1101.08 1145.07 1144.17 1730.76 0 200 400 600 800 1000 1200 1400 1600 1800 2000 shale coaly shale coal soft coal Productionrate(t/h)