Optimization of waste handling in surface mines
- 2. OPTIMIZATION OF WASTE HANDLING IN SURFACE MINES
- 3. INTRODUCTION The prime objective of waste dump planning is to minimize the vertical and horizontal distance between source and disposal area. Other factors like stability, availability of dumping area, environmental hazards, types of equipments used etc. usually act counter to above objective. Therefore, it is necessary to determine basic factors governing the waste dump plan for an opencast mine
- 4. OBJECTIVE (1) To study factors governing waste handling in opencast mines. (2) To optimize the waste handling capacity of an opencast mine.
- 5. PARAMETERS AFFECTING WASTE HANDLING CAPACITY OF A MINE
- 6. ECONOMIC PARAMETERS 1) Minimize the horizontal and vertical distance of the source to disposal area , 2) Deciding type of dumping ( in-pit or ex-pit) 3) cost of establishing a safe dump.
- 7. DESIGN PARAMETERS (1) Economic :- I. Minimize vertical and horizontal distance, II. Minimize the current haulage cost versus the discounted future re-handling cost of in-pit dumps.
- 8. (2) Non-economic:- i. Stability, ii. Political or surface rights, iii. Environmental considerations, iv. Physical configuration of dumps, v. Method of placement, vi. The planned development schedule.
- 9. GENERAL ENGINEERING 1) Swell factor of the run-of-mine, 2) Compaction ratio, 3) Angle of repose of the dump material, 4) Supportive surface strength of dump material, 5) Other factors
- 10. OTHER FACTORS Distribution at the time of a new dump, Notching of low levels of the dump, Removal of vegetation and other unconsolidated material for obtaining a stable base, End dump from pit head for good draining pattern, Properly placing the drainage structures like culvert pipes etc.
- 11. OPERATING CONSIDERATIONS 1) A slight positive gradient should be maintained at the dump to ensure that the run off will drain away from crest to natural ground. 2) Positive gradient is also good as the haul trucks will have to power back to dump rather than roll back. 3) In cases where the dump failure is serious, then an alternative dump location will have to be used until the situation is corrected. 4) For stabilizing dump failure we can put a layer of lower dump on the toe of the failure
- 12. CASE STUDY Preparing a case study on the waste dumping management of a mine having both in-pit and ex-pit dumps. Finding sites for in-pit and ex- pit dumping in the mine.
- 13. PROBLEM STATEMENT Previously the mine had 2 box cuts, one in A block and another one was in B block to reach the requirement of 8Mtpa. Ex-Pit dump was placed in North-West side of A block. With changes in mine sequence (i.e. start of mine from B block with 5.0mtpa capacity) we need to find place of dumping overburden.
- 14. INTRODUCTI ON The combined area of the blocks is 7.81km2 . The topography over the coal bearing area is gently undulating , but rises steeply to the north from the block boundary. The coal seams are steeply dipping and the blocks are intersected by several faults. There is total of over 20 named seams varying in thickness up to 7 m, but generally 1 to 2 meters. Strip ratio is 5.16 bcm/t (bank cubic meters per tonnes) A and B blocks contain 2 blocks 1) West block (A block) 2) East block (pachmo)
- 15. INTRODUCTION OF KBP BLOCK A- Block B Block B’s Nallah A Block B Block Area - 865.63 Area -1065.89
- 16. STUDY OF TOPOGRAPHY OF KBP BLOCK B-Block Rl-330 Rl-360 Rl-330 Rl-350 Rl-370 Rl-370 1. General Topography of Block is dipping down from West to east and North to South. RL is varying fro n 330 min to 380 maximum. 2. There is no perennial nala within Pachmo block bout water may ingress from Northern
- 17. STUDY OF COAL BEARING AREA IN AND AROUND BLOCK B-Block Non Coal Bearing area within block Coal Bearing area Coal Bearing area of other mine
- 18. EX-PIT DUMP 30M 30M 30M 30M30M 37.5˚ 37.5˚ 90 M28˚ • IN-PIT DUMP 30M 30M 30M 10M 37.5˚ 40M 28˚ STUDY OF RULES AND REGULATIONS - EC condition - Mining Plan - By-Laws Conceptual dump configuration Terrace angle- 37.5 deg Aver all dump Slopes- 28deg
- 19. PRODCUTION SCHEDULE FOR 5.0 MTPA COAL FROM PACHMOY1 Y2 Y3 Y4 Y5 Y6 Y7 Y8 Y9 Y10 Y11 Y12 Y13 Total Coal -mt 0.3 1.6 3.5 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 2.5 1.0 49.0 OB - mbCuM 1.5 8.0 17.5 25.0 25.0 25.0 25.0 25.0 25.0 25.0 25.0 12.5 5.0 245.0 Terrace wise ROM Coal -MT EBC 0.3 1.0 2.3 1.9 5.5 ET1 0.6 0.6 1.6 2.0 2.0 2.0 0.8 9.5 ET2 0.6 1.6 2.0 1.6 1.6 1.6 0.6 9.6 ET3 1.0 1.4 1.4 1.4 2.7 2.7 2.7 1.1 14.2 WT6 1.3 1.3 1.3 1.3 1.5 0.4 7.0 WT5 0.5 1.0 1.0 0.6 3.1 Total 0.3 1.6 3.5 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 2.5 1.0 49.0 Terrace wise OB-Mbcum EBC 1.5 5.0 11.5 9.5 28.0 ET1 3.0 3.0 7.8 10.0 10.0 10.0 3.8 48.0 ET2 3.0 7.8 10.0 8.1 8.1 8.1 2.9 48.0 ET3 5.0 6.9 6.9 6.9 13.4 13.4 13.4 5.3 71.0 WT6 6.3 6.3 6.6 6.6 7.3 2.0 35.0 WT5 2.5 5.0 5.0 2.8 15.0 Total OB 1.5 8.0 17.5 25.0 25.0 25.0 25.0 25.0 25.0 25.0 25.0 12.5 4.8 244.0 •Total OB Generation will be 245 mbcum. ( 342 Loose MCuM ) •The overburden generated needs to be disposed either In-Pit or Ex-Pit • Effort should be there to minimize ex-pit dumping and maximize in-pit dumping
- 20. STUDY OF ULTIMATE PIT OF PACHMO +10m +190m +280m +330m Non Coal Bearing Area=60 ha Depth of Mine 290mtra Width- NS 1.3 KM Width EW- 2.4 KM Rom reserves- 48 mt +100m B’s Nallah Pit advance direction (East to West
- 21. A B Section Along - AB B’s Nallah EBC 5.5 ET1 9.5 ET2 9.6 ET3 14.2 WT6 7 WT5 3.05 Total 48.85 ROM reserves STUDY OF TERRACE SEQUENCING BCET 1 ET 2 WT-6 ET 3 WT-5 Pit advance direction (East to West
- 22. POSSIBLE LOCATIONS OF DUMPING WASTE Dump-1: Dumping over coal bearing area located towards end of pit Dump-2: Dumping over non-coal bearing area in North- East Part. Dump-3: Dumping Ex-Pit along northern boundary. Dump-4: In-Pit Dumping along with mining. Dump-1 Dump-2 Dump-3 Dump-4
- 23. CRITERIA FOR IN-PIT DUMP SEQUENCING 1st In –Pit dumping can be done after the completion of Box- Cut. Subsequent in-pit dumping is only possible after completion of each terrace. There should be space of around 200mtrs from the toe of In pit dump and bottom of pit Ultimate pit Geometry should be favorable for in-Pit Dumping. 45 deg BC T1T2 T3T4 200mtrs
- 24. DUMP SPACE AVAILABLE Dump-1: 12.4 M CuM ( to be re-handled) Dump-2: 16.8 M CuM Dump-3: 202 MCuM + 12.4 MCuM Dump-4: In- Pit Dump -1: 12.5 MCuM In-Pit Dump-2 : 35.4 MCuM In –Pit Dump-3 : 57 .6 MCuM Dump-1 Dump-2 Dump-3 Dump-4
- 25. OVER BURDEN DUMPING SEQUANCE Y1 Y2 Y3 Y4 Y5 Y6 Y7 Y8 Y9 Y10 Y11 Y12 Y13 Total Total Loose OB Mbcum 2.1 11.2 24.5 35.0 35.0 35.0 35.0 35.0 35.0 35.0 35.0 17.5 6.7 342.0 AVAILABLE DUMP SPACE IN MBCUM Dump-I 12.4 Dump-2 16.8 16.8 In-Pit BC dump 12.5 12.5 In-Pit T1 dump 35.4 35.4 In-Pit T1 dump 57.6 57.6 Total 29.1 12.5 35.4 57.6 122.2 Internal dumping-MCuM 2.1 11.2 15.8 12.5 35.0 35.0 27.5 139.1 External Dumping - MCuM 8.7 35.0 22.5 35.0 35.0 35.0 7.5 17.5 6.7 202.8
- 26. PIT POSITION AT END OF BOX CUT ( Year -4 Dump-1 Completed 12.4 mCuM Dump-2 Completed 16.2 mCuM End of Box Cut T-1, T2 & T3 in operation Ex-Pit Dump in operation 44 mCuM
- 27. IN PIT DUMP-1 AFTER COMPLETION OF BOX CUT ( Year -5) T-1, T2 & T3 in operation Ex-Pit Dump in operation In Pit Dump-1 12.5 MCum
- 28. IN PIT DUMP-2 AFTER COMPLETION OF TERRACE T-1 (Year -9) T-2, T3 & WT6 in operation Ex-Pit Dump in operation In Pit Dump-2 35.4 MCum Dump-1 has been re-handled
- 29. IN PIT DUMP-3 AFTER COMPLETION OF TERRACE T-2 (Year -10) T-3, WT-6 & WT5 in operation Ex-Pit Dump in operation In Pit Dump-3 57.57 MCum
- 30. ULTIMATE VOID AFTER -13 YEARS ( END OF LIFE OF MINE) T-3, WT-6 & WT5 in operation Ex-Pit Dump in operation ( 296 HA) 212 MCuM In Pit Dump-1 ,2 ,3 105 MCum Total Void – 173 MCuM
- 31. CONCLUSIONS 1. Ex-Pit dumping space is essential for 5.0mtpa within 2 & ½ year. 2. Ex-Pit dump space should be acquired within 2 &1/2 year for sustaining production level. 2. The area required for ex-pit dumping space is 296 hector. 3. Due to faster rate of production big ultimate void is formed. 2. However, ultimate void can be used if we continue mining in KB Block.