MineVue Radar For Delineation Of Barrier Thickness To Mitigate Inundation In Underground Coal Mines

by Dr. K. K. K. Singh, Sr. Principal Scientist CSIR- Central Institute of Mining & Fuel Research ,

Central Institute of Mining & Fuel earch,Dhan INUNDATION

Sudden heavy inrush of high volume of water from the unapproachable and abandoned waterlogged workings in underground mines is defined as inundation. MAJOR CAUSES OF INUNDATION

• Accidental connections of present mine workings to old unapproachable abandoned waterlogged workings.

• Accidental connections to natural bodies of water.

• Deeper mines overlain by a water-bearing strata.

• Mine workings connected to old waterlogged quarries.

• Sudden and unprecedented inflow of surface water to underground mine workings.

• Faults bring the aquifer in contact with the worked out coal seam & immediate heavy inrush of water. Disasters Caused Due to Inundation in Underground Coal Mines of Name of mine Date of occurrences Persons killed Phularitand Colliery 11.07.1912 21 Colliery 16.01.1935 11 Makerwal Colliery 06.07.1942 14 Newton Chikli Colliery 10.12.1954 63 Burra Dhemo Colliery 26.09.1956 28 Cen. Colliery 20.02.1958 23 Damua Colliery 05.01.1960 16 Silewara Colliery 18.11.1975 10 Chasnalla Colliery 27.12.1975 375 Central Saunda Colliery 16.09.1976,15/6/2005 10, 14 Hurriladih Colliery 14.09.1983 19 Mahabir Colliery 13.11.1989 6 Gaslitand Colliery 27.09.1995 64 Bagdigi Colliery 02.02.2001 29 Godavari Khani–7 LEP 16.06.2003 17 Colliery Directorate General Of Mines Safety (Tech) Circular of 2003

“Penetration up to 60 m depth in Coal” GROUND PENETRATING RADAR (MINEVUE RADAR) OPERATING PRINCIPLE A very short time impulse(ns) of EM waves is generated at a very high frequency (12.5 MHz to1 GHz) antenna, transmitter. When the signal encounters an anomaly, it is reflected and picked up by a receiver which transmits it to a Data logger. Two-way travel-time measured in nanoseconds(1ns=10-9sec.): D = T. V/2 & V = C/. 5 D=depth to reflector (m), T=two-way travel time(nanosecond) C = velocity of light in free space=0.3m per nanosecond, = relative dielectric permittivity, a dimensionless ratio, V = electromagnetic wave velocity, in meter/nanosecond. Working Principle

Reflected Transmitted wavefront wavefront Direct wave

Reflected wave MineVue Radar Deepest penetrating shielded radar in the world

First single-board radar in the world

First intrinsically safe radar in the world – Certification by BASEEFA,U.K.& DGMS, Dhanbad

Smallest low-frequency radar in the world

First real-time sampling radar (64,000 stacks) Surface Survey Surface Survey MINEVUE

Underground Survey Underground Survey Colliery, Coalfield,Dhanbad

Fault Fault

4.5 m

Gallery

33 33 L

34 34 L

35 35 L

GPR Traverses

Scale-m 0 20

Radar traverse between 35th to 34th Levels, Seam III of Tetulmari Colliery (Dry Gallery& Fault). Tetulmari Colliery,,Dhanbad

Fault

Fault 4.5 m

33 33 L

34 34 L

35 35 L

GPR Traverses Gallery

Scale-m 0 20

Radar traverse between 34th to 33rd Levels, Seam III of Tetulmari Colliery (Dry Gallery& Fault). Bansudeopur Colliery,Jharia Coalfield,Dhanbad

0L PIT 4 21R

Waterlogged

gallery 20R

GPR Traverse

Fault Fault

Scale-m 0 30

Radar traverse along 0 Level obetween 20th and 21st Rise, Bansudeopur Colliery (Waterlogged Gallery Gallery & Fault). Kachhi Balihary Colliery, Jharia Coalfield, Dhanbad

2nd X-Cut Scale-m 0 20 7 DIP 8 DIP

Gallery Radar traverse along 7th Rise of 2nd X-Cut, K.B. Colliery (Waterlogged gallery) Kachhi Balihary Colliery, Jharia Coalfield, Dhanbad

Scale-m nd 2 X-Cut 0 20 7 DI 8 P DI P

Gallery Radar traverse along 2nd X-Cut between 7th & 8th Dip, K.B. Colliery (Waterlogged gallery) Bhagabandh Colliery, Jharia Coalfield,Dhanbad

Gallery Gallery Gallery Gallery Gallery

Gallery Gallery Gallery

STARTING POINT

FINISHING POINT

Scale-m 0 20 Radar traverse on the surface over 18th Seam at Aralgoria, Bhagabandh Colliery CONCLUSIONS  World’s first intrinsically-safe & longest range of 60 m.  Smallest low frequency (40 MHz) shielded radar.  First of its kind designed specifically for gaseous underground coal mines in the world.  DGMS, Mine Safety Regulatory Authority, granted permission for use in gaseous underground coal mines.  Bench marking development for the safety of miners and machineries where coal is blocked in abandoned inaccessible waterlogged workings.

FUTURE R&D  For more portability - Reduce the size & weight.  For better penetration – Increase the transmitter power Thank You