Presentation on

GAINFUL UTILISATION OF PROCESSED OVERBURDEN OF OC MINES:

SCCL EFFORTS

By

Dr. M.S. Venkatramyya, Addl GM (Estates)

M. Ranga Rao, DGM (CP&P)

Md. Fazal Hussain, Dy. Manager (R&D)

Sand stowing scenario in SCCL

• In view of multiple advantages, sand stowing is gaining prominence in underground mining.

• Stowing which was introduced in early 60s in No 5 Incline, Kothagudem has spread to a number of mines and today 22 mines out of 36 underground mines are practicing sand stowing.

YearTotal prod.(in MT.)

Prod.by OC(in

MT.)

Prod.by UG

(in MT.)

UG prod. Caving/Dev in HS /M&M

UG prod. by

stowing(in MT)

Sand Stowed(million

m3)

No. of Mineswith

stowg

2005 - 06 36.14 23.43 12.71 11.61 1.10 1.25 15

2006 - 07 37.71 25.83 11.88 10.44 1.44 1.60 17

2007 - 08 40.60 27.96 12.65 10.59 2.06 2.00 16

2008 - 09 44.55 32.46 12.09 9.67 2.42 2.40 15

2009 - 10 50.43 38.46 11.97 9.34 2.63 2.64 13

2010 - 11 51.33 39.72 11.61 9.12 2.49 2.47 16

Requirement of sand for the next 4 years

Area

2011-12 2012-13 2013-14 2014-15

Coal(T)

Sand(m3)

Coal(T)

Sand(m3)

Coal(T)

Sand(m3)

Coal(T)

Sand(m3)

1 KGM 2.00 2.60 4.00 5.2 4.00 5.20 4.00 5.20

2 MNGR 1.67 2.26 0 0 0 0 0 0

3 RG-I 15.48 19.02 14.70 17.90 17.56 21.52 17.56 21.52

4 RG-II 4.00 5.22 1.60 2.10 1.60 2.10 1.60 2.10

5 RG-III 3.00 2.40 3.00 2.40 3.00 2.40 3.00 2.40

6 BHPL 9.39 11.15 9.39 11.35 10.26 12.08 10.94 12.80

7 SRP 15.59 17.33 15.59 17.33 15.59 17.33 14.68 16.33

8 MM 3.00 3.89 3.00 3.89 3.00 3.89 3.00 3.89

9 BPA 1.00 1.40 1.00 1.40 1.50 2.10 1.50 2.10

TOTAL 55.13 65.27 52.28 61.57 56.51 66.62 56.28 66.34

(all figs in lakhs)

• About 66 lakh cum of sand per annum is required in the next four years.

• The requirement may further go up with the introduction of Continuous miners in conjunction with sand stowing from safety and conservation point of view at higher depths.

Need for OB processing

• Though a number of sand stowing plants in SCCL have efficiency to stow sand at the rate of about 100 cum per hour, the delay in filling underground voids is due to hindrance in the supply of sand from long distances.

• Especially in rainy season the inclement weather and slushy conditions in the premises of river bed would further affect the transportation of sand.

• In addition to that if the area awarded to sand transport contractor contains clay bed or large pebbles, it badly affects the stowing rate.

• Number of persons are to be deployed to remove the clay and pebbles at the mixing tough in every shift which reduces the productivity and retards the stowing rate.

Need for OB processing

• Sand obtained by processing OB is free of clay, pebbles and any other extraneous material and eliminates all the above problems. As the OB processing plant is in the close vicinity of mines and continuously available/ accessible round the clock, it is reliable in stowing large quantities and thus can be confidently worked in conjunction with large scale mechanization.

• When processed OB is used in stowing or other gainful purposes, considerable land acquisition can be avoided.

• It is also established that the clay produced during processing has got value addition as it can be used in ceramic industry and in the tiles industries located in the vicinity of mining areas.

Pebbles and clay from river sand

Tiles made with Clay

SCCL Production and OB removal

YEAR

Coal Prodn (LT) OB TOTAL

UG OC

removal (UG+OC)

Lack m3 Prdn (LT)

1975-76 73.58   1.04 73.58

1976-77 82.98   2.43 82.98

1977-78 89.12   3.40 89.12

1978-79 90.08   5.72 90.08

1979-80 91.99 2.04 7.94 94.03

1980-81 96.08 4.89 17.16 100.97

1981-82 109.29 11.74 29.87 121.03

1982-83 105.47 17.98 34.74 123.45

1983-84 109.23 17.64 31.65 126.87

1984-85 105.50 17.78 38.95 123.28

1985-86 132.36 24.19 53.47 156.55

1986-87 132.05 33.75 76.62 165.80

1987-88 125.65 38.36 91.34 164.01

1988-89 139.14 46.91 114.01 186.05

1989-90 120.32 57.73 178.82 178.05

SCCL Production and OB removal

YEAR

Coal Prodn (LT) OB TOTAL

UG OC

removal (UG+OC)

Lack m3 Prdn (LT)

1990-91 111.21 65.88 175.05 177.09

1991-92 123.49 82.34 201.51 205.83

1992-93 135.05 90.04 243.33 225.09

1993-94 151.56 100.53 304.50 252.09

1994-95 137.56 118.93 396.79 256.49

1995-96 131.64 136.06 518.89 267.70

1996-97 137.33 150.01 560.69 287.34

1997-98 136.21 153.20 610.55 289.41

1998-99 129.54 143.72 812.86 273.26

1999-2000 127.91 167.65 725.88 295.56

SCCL Production and OB removal

YEAR

Coal Prdn (LT) OB TOTAL

UG OC

removal (UG+OC)

Lack m3 Prdn (LT)

2000-01 137.87 164.87 896.57 302.74

2001-02 137.47 170.64 930.08 308.11

2002-03 128.08 204.28 1030.39 332.36

2003-04 133.14 205.40 886.84 338.54

2004-05 129.74 223.29 1016.36 353.03

2005-06 127.11 234.27 1155.83 361.38

2006-07 118.76 258.31 1373.53 377.07

2007-08 126.45 279.59 1407.07 406.04

2008-09 120.87 324.59 1849.92 445.46

2009-10 118.91 384.55 2467.94 503.46

2010-11 116.28 397.04 2144.74 513.33

Total OB Removed is 20396.48 lakh cum

• As opencast mines are existing in every area with abundant quantity of over burden material, it is felt that processing OB to extract sand is viable alternative.

• Since the introduction of OC mines in SCCL about 20396.48 lakh cum of OB was produced in SCCL till 2010-11.

Present scenario in the market

• During the last two decades, infrastructure build up activities are going at a fast pace, resulting in huge demand for sand. Recently in an auction for sand quarry having deposits of 9,000Cu.m was auctioned for about `.19.00 crores.

• Govt. of AP has been seriously exploring ways & means to reduce the load on sand quarries. On dt.15.11.2006, the Govt. of AP announced an ‘eco-friendly’ sand-mining policy, imposing a ban on use of machinery and restricting the depth for extraction to 2.0 m from river – beds and other water bodies. Restriction on the depth up to which the river bed could be excavated has been imposed to ensure proper flow in the river and thus save ecology. Govt. of AP also decided as part of the policy, use of rock sand will be encouraged in order to reduce pressure on riverbeds. (Clipping of the news item enclosed).

• Again on dt.17.5.2011, Smt Galla Arunakumari, Hon. Minister for Mines(AP) has given a statement to minimize the use of river sand and encourage use of artificial sand/alternative to sand.(Clipping of the news item enclosed).

Conclusions

• Keeping in view the above circumstances and demand in the market, SCCL can go ahead in a larger way by establishing bigger plants(10,000 Cu.m/day) at OC-II of Godavarikhani Area, where crushed and weathered OB is readily available which is best suitable for preparation of sand.

• As the processing of OB needs crushing, we can try to introduce in-pit crushing and conveying system in some more OC mines to avoid fleet of dumpers to bring the OB upto surface for crushing.

• The by-product of the process i.e. clay is also suitable for preparation of fire bricks, bricks, tiles and pipes.

Conclusions

• AP Mines & Geology Department, Hyderabad is favourable for giving permission for marketing sand for construction purpose depending upon its suitability and also clay on commercial basis as minor mineral.

• By providing sufficient land near the OB dumps, sand projects as well as Brick Manufacturing units can be established at the site itself.

• By diversifying activities in the above manner SCCL can make about `.50.00 Crores/annum depending on the capacity of the plant.