A REPORT ON TRAINING AT JADUGUDA URANIUM MINES, UCIL
DEPARTMENT OF MINING ENGINEERING BIRSA INSTITUTE OF TECHNOLOGY
Submitted by:Sujit Kumar 070849
1.
HISTORY OF URANIUM MINING IN INDIA
2.
GENERAL INFORMATION ABOUT MINE
3.
GEOLOGY OF JADUGUDA MINE
4.
GEOLOGY OF BHATIN MINE
5.
MINE SURVEY
6.
MINING METHOD EMPLOYED IN MINES
7.
STUDY OF VENTILATION
8.
MINING MACHINERY USED IN MINES
9.
DETAILS OF LAMP ROOM
10.
EXPLOSIVE AND BLASTING
11.
MOINTORING AND GRADE CONTROLL
12.
WASTE MANAGEMENT FROM MINING AND MILLING
1.
HISTORY OF URANIUM MINING IN INDIA
2.
GENERAL INFORMATION ABOUT MINE
3.
GEOLOGY OF JADUGUDA MINE
4.
GEOLOGY OF BHATIN MINE
5.
MINE SURVEY
6.
MINING METHOD EMPLOYED IN MINES
7.
STUDY OF VENTILATION
8.
MINING MACHINERY USED IN MINES
9.
DETAILS OF LAMP ROOM
10.
EXPLOSIVE AND BLASTING
11.
MOINTORING AND GRADE CONTROLL
12.
WASTE MANAGEMENT FROM MINING AND MILLING
JADUGUDA MINE & BHATIN MINE (UNDERGROUND MINES OF UCIL)
HISTORY OF URANIUM MINING IN INDIA Some forty-five years ago, when Dr. Bhabha initiated the development of nuclear energy, two decisions were taken; first was to construct CIRUS reactor and second was to work on production of uranium metal fuel in country. In year 1956, task of producing uranium metal was assigned to group called “Project Firewood”. For producing nuclear fuel it was necessary to search for the uranium deposit in country. As early as in 1937 a sample of uranium is picked up by a prospector from one of copper mines in singhbhum thrust belt. In 1960, a close examination of this 160 km long mineral zone, out cropping on ridge of hill, which could be sizeable potential, was revealed at Jaduguda. This turned out to be major deposit and has remained best so far. In 1961, decision was taken to open up mine and mill and in 1967 Jaduguda mine has become full fledged operational and is developed to depth to depth of 905m. The central shaft serves as entry for men and material and main ventilation intake route. Subsequently, three deposits at Bhatin Narwaphar and Turamdih located 3, 12, 25 KM north west of Jaduguda were taken up for underground mining in 1986, 1995, 2002 respectively. Mine construction work has already been started in Bagjata mine located 11 Km east of Mosaboni copper mine. Opening of an opencast mine at Banduhurang, adjacent to Turamdih mine is in very advance stage and pre-project activities for opening of another underground mine has been taken up at Mohuldih, west Banduhurang mine. Shortly, there will be soon operation uranium mines in singhbhum district of Jharkhand over a stretch of 80 KM from in Bagjata in east to Mohuldih in west. To meet the nuclear fuel demands of the country (20,000 MWe by 2020), it has become necessary to exploit all the proven uranium reserve in the country. Most the reserve in singhbhum thrust or gang to be taken up for exploitation. UCIL intends to exploits the known deposits at Lambapur-Peddagatta in the district of Nalgonda, Andhra Pradesh and Domiasiat-Mawthabah in west Khasi hills district of Meghalaya. The uranium ore in India is generally of low grade containing uranium between 0.032 to 0.16Therefore, large quantity of ore has to be mined to get reasonable quantity of uranium. Banduburang is the first open cut mine and is being commissioned in 2007, Bagjata is underground and has production started from 2008, though there had been earlier small operations 1986-91. The Mohuldih underground mine is expected to operate from 2010. The Pulivendula mine and mill project in Kadapa district of Andhra Pradesh was approved in February 2007.
India's uranium mines and mills - existing and announced : State, district
Mine
Mill
Jharkhand
Jaduguda Bhatin Narwapahar Turamdih Banduburang Bagjata Mohuldih Mawthabah Lambapur-Peddagattu Tummalapalle Pulivendula
Jaduguda Jaduguda Jaduguda Turamdih
Meghalaya Andhra Pradesh, Nalgonda Andhra Pradesh, Kadapa Andhra Pradesh, Kadapa
Mawthabah Seripally Tummalapalle Pulivendula
Operating from 1967 1967 1995 2002 (mine) 2007 2008 2010 ? ? 2010 ?
However, India has reserves of 290,000 tonnes of thorium - about one quarter of the world total, and these are intended to fuel its nuclear power program longer-term
GENERAL INFORMATION ABOUT MINE Name :Jaduguda Mine 0 0 Location :Latitude 22 39 N 0 0 Longitude 86 20 E TOWN :Jamshedpur Post Office :Jaduguda mines Railway station : - Rakha mines railway station District :East Singhbhum Name and address of 1. Owner : -Shri R. Gupta, C&MD Uranium Corporation of India Ltd 2. Agent :GM (MINES), UCIL (Jaduguda/Bhatin/Bagjata) 3. Manager Shri M.K. Bera
Shri S.C. Bhowmik
: - Shri Manoj Kumar (Bhatin mines)
Approximate life of mine: -
50 yrs.
(Jaduguda mines)
Approximate remaining life of mine : - 10 yrs. Average monthly output Average daily output Number of lode present
: - 50,000 Te : - 650 Te :- 2 A. HANGWALL LODE B. FOOTWALL LODE
Both are being worked. Most prominent and higher grade of ore is formed in footwall lode. Geological disturbances are at footwall side. Faults, folds, and joints are found at this side.
Depth Thickness and Inclination of Lodes:Name of lode
Thickness
Inclination 0
Footwall lode
5m-20m
45
Hangwall lode
3m-4m
45
0
Footwall lode confined to western side of shaft and also occurs in eastern side of shaft. In footwall lode strike length decreases from 1000m to 600m below 450m from surface. In hangwall lode, strike length varies in between 300m-350m from surface. Upto the depth of 250m no large variation is found in strike length but reduces to 250m after the depth of 650m. It is completely uniform and no disturbances are found. Width increases due to low angle strike fall along which molybdenum mineralisation has taken place. Rock fall occurs in western side due to molybdenum. In centre portion of Jaduguda epidorite interveins the strata hence causes ore loss.
GEOLOGY OF JADUGUDA MINE INTRODUCTION Jaduguda uranium deposit is located almost in the center of Singhbhum Thrust belt. The deposit was discovered in 1951 by Atomic Mineral Division. After a detailed prospecting and exploratory mining, the deposit was found suitable for commercial exploitation. Mining operation was initiated in Jaduguda during 1964 and regular production started from 1966.The mine is designed to produce 1000 tons of ore per day.
GENERAL GEOLOGY Uranium mineralisation in Jaduguda is confined to sheared rock types o f Singbhum Thrust Zone. Geologically, the thrust belt is constituted by Archean metasediments such as mica-schist, quartzite, phyllites and altered tuffs. The rocktypes in this zone are broadly classified into two groups – the older Chaibasa stage of rocks consisting of metasediments and the younger Dhanjori stage of rocks consisting of metavolcanics.
During shearing, the older Chaibasa stage of rocks is thrust over younger metavolcanics of Dhanjori. As a result, the younger Dhanjori stage of rocks lie below the older Chaibasa stage of rocks. The thrust contact between two stages of rocks is severely sheared and brecciated. Uranium occurs in this sheared zone in very finely disseminated form.
ROCKTYPES: -
The rock types seen in Jaduguda hill from north to south are – Garnetiferous-muscovite schist Quartzite (cherty) Muscovite-kyanite-quartz schist
CHAIBASA STAGE
Mylonite Quartz breccia Conglomerate (autoclastic) Quartz-chlorite-biotite-apatite-uraninite schist (Granular rock) Chlorite-biotite-quartz rock
Talc-chlorite schist
SHEARED ZONE
Coarse grained quartzite Epidiorite with intermittent thin quartzite
DHANJORI STAGE
These rocks are of varying thickness both along strike and dip. Of all the rock types, the cherry quartzite bed of Chaibasa stage, because of its persistency, is considered as MARKER BAND. It is about 2m wide. HOST ROCK Though all the rocktypes around Jaduguda contain some amount of uranium, the economic concentration of uranium is confined to only the following metasedimentary rocks of Chaibasa stage –
1. Autoclastic conglomerate 2. Granular rock From uranium concentration poit of view, the best mineralised rocktypes are the autoclastic conglomerate. The micaceous schists are poorest in uranium content. All mineralised rock types show schistosity when examined as thin section under microscope. Even the granular rock, which is composed of chlorite-biotite-quartztourmaline-apatitie-ilmenite-magnetite and uraninite, is seen to be schist under microscope.
It has also been observed that, there are zones of granular rock and autoclastic conglomerate in the mine where the imprints of shearing are very little. Such zones are normally devoid of uranium. The associated accessory minerals found along with uranium are the sulphide minerals of copper, nickel and molybdenum. Magnetite is also another accessory mineral abundantly found along with uranium. The uranium ore of Jaduguda is amenable to direct leaching by acid with about 94% recovery.
OREBODY CONFIGURATION Mineable mineralisation at Jaduguda is confined to two principal lodes – known as Footwall Lode (FWL) and Hanging wall Lode (HWL) - extending as veins following the general trend of the schistosity. Persistence of lodes is fairly uniform both along strike 0 0 (N320 ) and dip (towards NE) with an average inclination of about 40 . Both the lodes are parallel and separated from each other by a distance of about 80m. FOOTWALL LODE (FWL):
It is the principal lode in Jaduguda Mine with a strike extends of about 1000m near surface, but gradually reduced to 600m at 495ml. However, no further shrink is observed up to a depth of 685ml. This lode has been prospected up to a vertical depth of 720m and is expected to continue up to a depth of about 900m. The FWL is not uniform either in width or concentration of uranium minerals. The western side of the lode is rich in uranium concentration and the maximum true width of about 10m. The grade varies from 0.06% to 0.1% eU3O8. In this zone, there are at least two prominent parallel strike slip shears which are mineralised with molybdenum. About 1m wide rock around this shear zones is highly crushed and pose rock fall problem during mining. However, the in-house geo-technical study carried out in this area has helped in designing the support pattern. SKETCH OF WESTERN SIDE OREBODY
In the eastern side, the average true width of FWL is about 2.5 to 3m. The grade varies from 0.075 to 0.06% eU3O8. The footwall lode is cut across by a basic intrusive (epidiorite) in the central portion. The width of this intrusive varies from 10 to 25m and has a general shift towards west in deeper levels. This results in loss of ore of about 20m strike length in Footwall Lode. The hangwall side rocks of FWL are quite competent. In the footwall side, the talcchlorite schist (shear zone) rock is highly friable and soft. The width of this Zone varies from 2 to 30m resulting in instability to any development headings in the footwall side. HANGWALL LODE (HWL):-
The HWL is present only in the eastern side of the mine. It is extended over a strike length of about 300m in the upper levels. This lode is continuous along strike up to 295m vertical depth. Below 295ml, a low grade patch of about 50m strike length occurs in the centre of the ore body. As a result, the mineable strike length of HWL is reduced to only 250m in deeper levels stretched over two separate blocks along the strike. The average true width of this lode is about 2.5m. Unlike footwall lode, hangwall lode does not show much variation in grade and width. No major geological disturbance is observed in HWL. Both footwall and hangwall side rocks of this lode are fairly competent. Exploration holes drilled from surface by AMD do not show any indication of hangwall lode below 555ml. Development of 620ml has also confirmed the gradual disappearance of this lode with depth below 555ml.
MINERALOGY: -
The primary uranium minerals in Jaduguda are uraninite and pitchblende. The common secondary uranium mineral is autonite. The uranium minerals are associated with a wide variety of sulphides of copper, nickel, cobalt, molybdenum, arsenic, bismuth. Apatite and magnetite are common associates and found as high as 10% to 15% at places.
PROMINENT STRUCTURAL FEATURES The principal planar structures in Jaduguda mine are foliation planes, joint planes and shear planes.
The foliation planes are the dominant planar feature in the mine. Since these planes do not show any abrupt anisotropy, they do not affect the stability of rock.
There are three sets of joint planes present in the rocks. J1 -
The most prominent one is nearly parallel to foliation strike but having dip 0 0 30 to 50 towards SW (opposite to the uranium lode). A few of them are nearly vertical.
J2 -
The second set of joints are the dip joints which are vertical or having dip 0 0 30 to 50 towards NW or SE.
The principal shear planes are confined to western side only. These are the low angle strike-slip shears mineralised with molybdenium nearly parallel to the foliation dip and 0 0 makes an angle of 15 to 20 with the foliation strike of the rock. The width of this zone varies from few mm to 80mm. Of the above planar features, the molybdenum shear plane, J1 and J2 are treated as discontinuity planes (from geo-technical point of view). These planes, in combination, create some unstable blocks specially in the western section of the mine.
PHYSICO-MECHANICAL PROPERTIES In Jaduguda mine, the host rock and the adjoining strata are quite competent except the talc-chlorite schist zone in the footwall side. The table below gives the variation of uniaxial compressive strength (UCS) and tensile strength (TS) of rocks at different depths.
2
2
DEPTH (m) Unconfined Compressive Strength (Kg/cm ) Tensile Strength (Kg/cm )
295
473
115
555
613.53
89.65
815
984.43
116.12
865
659.93
112.73
The increasing trend of uniaxial compressive strength of rocks with depth indicates better competency and self supporting nature of rock. Some other physico-mechanical properties of rocks have also been studied at different depth.
The values are given as follows. PROPERTIES
555ML
DENSITY
2.85 g/cm
2.78g/cm
2.95g/cm
MOISTURE CONTENT
0.143%
0.31%
0.14%
COHESIVE STRENGTH
146.66kg/cm
ANGLA
815ML 2
OF
865ML 2
2
2
2
2
162.5kg/cm
0
141.66kg/cm
0
INTERNAL 40
42.5
42.3
0
FRICTION 2
2
2
YOUNG’S MODULOUS
115384.5kg/cm
183333.3kg/cm
153525.6kg/cm
POISSION’S RATIO
0.335
0.210
0.550
POROSITY
1.7%
1.7%
1.2%
PERMEABILITY
0
0
0
GEOLOGY OF BHATIN MINE The Bhatin deposit located 4 km northwest of Jaduguda deposit. A major fault occurs between two deposits. The Bhatin mine came into production in 1986. The ore body has a 0 thickness of 2 to 10m and an average dip of 30 to 40 . The geology is similar to Jaduguda deposit. The host rock is chlorite-biotite schist. The small deposit is developed using adits and inclines and is mined using the cut and fill method. Trucks are used for transport the ore to the Jaduguda mill.
TYPE OF OPENING: In Jaduguda mine, mine entry is from a shaft. This shaft serves the purpose of ventilation as well as men riding and material handling. The circular, concrete-lined main mine shaft has a diameter of 5 metres and it sunk to a depth of 640 m. It was sunk in two stages- the first stage went to a depth of 315 m and the second stage from 315m. Later, an auxiliary third shaft to a further depth of 350 m was sunk. The three shafts together to a depth of 990 m.On top of the shaft and on the surface is a 41-m concrete tower that houses machinery. Two multi-rope friction winders control the skip and the cage. The skip can
haul 5 tonnes of ore at a time from a loading station situated 605 m below the surface. The cage has two decks to transport men and materials. In Bhatin mine, mine opening is an adit. Adit 4 serves the purpose of travelling of men and material handling. After entering the mine from adit 4 a decline is used (at an angle 0 of 45 ) to reach various levels by skip. There are seven levels in Bhatin mine. Doubledrum winder is used to haul skip in the incline. st
ADIT
1 and 2 (in 1 level) ADIT
ADIT 1&2
nd
3 and 4 (in 2 level) used for exit
ADIT 3
used for ventilation
ADIT 4
used for travelling of men
PARTICULARS OF WINDING ROPE: Rope diameter
19mm
Rope length
500m each drum
Construction
6 7 R.H. lay
Breaking Load
212 KN
Date of installation
8.7.07
Date of last recapping
25.1.09
Due date for next recapping 26.7.09 Main safety devices(1) depth indicator (2) overwinding limit switch (3) overspeeding ,limit switches
MINE SURVEY Survey section serves various functions at Jaduguda as well as at Bhatin mine. These function involves bore hole data logging for deciding geological structure, lodes, dip of ore body, etc. It provides plan and section as per the requirement of the particular mine. Surveyor maintains the daily record for the advance of drift and drives. It checks the drilling while development of raises and winzes. The surveyor’s helper marks the “waste/ore” in the drives and stopes so as to save economic loss. Survey section as well as Physics section checks the driving of drift and drives in proposed manner. Ventilation
survey and other survey to assist the various sections are done by the survey section. There are more other operations and functions are done by survey section for execution of good work.
LAYOUT OF PLANNING AND SURVEY SECTION
EQUIPMENT USED IN SURVEY SECTION Theodolite(LC-20”) Theodolite(LC-10”) EDM Auto Nadir Plummet Zenith plummet
Laser eye piece Total station
2 NOS. 2 NOS. 1 NOS. 1 NOS. 1 NOS. 1 NOS. 1 NOS.
Computer desk are used for AUTOCAD and SURPAC.
RL AND LEVEL DISTANCE OF BHATIN MINE
RL AND LEVEL DISTANCE OF JADUGUDA MINE
Figure. TRANSVERSE SECTION ACROSS JADUGUDA HILL
Figure. TRANSVERSE SECTION ACROSS JADUGUDA MINE
MINING METHOD EMPLOYED IN MINES Stoping is a process of extraction. There are a number of methods of stoping. The method of stoping depends in the nature, shape, size of the ore body and the strength of the wall rocks.
In Jaduguda “Cut &Fill” stoping method is fo llowed using deslimed mill tailings as back fill. The broken ore is mechanically handled using Load Haul Dump (LHD) equipment. Ore-pass, ore is loaded in 3.5 tonne capacity Granby cars. These mine cars are hauled by diesel locomotive for automatic dumping into the main ore-pass system. The main tramming drive in each level is developed in footwall side of ore. By this way no ore is left in pillars. In cut&fill method percentage recovery of ore is about 80% approximately and is ideally suited for Jaduguda mine. In the last decades ramp mining system is introduced to stope out the 15 to 20 m wide open bodies available in 495ml and 55ml replacing pneumatically operated mining equipments with more energy efficient electro hydraulic mining machines like single boom drill jumbo for face drilling, electrically operated EJC loader for clearing the blasted muck. The output per man per shift has gone up from 10 tonnes in conventional stoping to 20 tonnes per man per shift. In addition, this mining equipment is environment friendly. Exploratory boreholes was drilled and auxiliary shaft was sunk from 555ml to the depth of 905ml. The location of this shaft is 580 metres north of main shaft. Deepened mine rd area where this auxiliary shaft was sunk is called as 3 stage. Bhatin mine is 3km away from Jaduguda mine having average ore body width varies from 2.5 to 7 meters. The stoping method is horizontal cut&fills using deslimed mill tailings as backfill material. AMD had done all exploratory mining work involving development of five levels and th now it is full developed up to 7 level. Blasted muck is hauled using hooper loader and transported by dumpers to Jaduguda mill for processing.
UCIL’s operational performance has been excel lent all through operating at 80-85% capacity in mining, and 96% capacity in mill. An impressive track record has been established in the execution of new project and technological sophistication. UCIL has in-house expertise for mechanised shaft sinking, equipping and commissioning of winder, Development of declined, drift and long raises.
STUDY OF VENTILATION Ventilation system used in Jaduguda mine as well as in Bhatin mine is descentional boundary ventilation. Air delivered through the main shaft reaches the boundary of sha ft then comes out of the mine by ventilating all the levels through raises. Ventilation is good at all levels. Air enters through adit in Bhatin mine and gets well distributed. Two fans are present in Jaduguda mine of 250kw.
SPECIICATION OF VENTILATION FAN PV160 FAN SL.NO. ITEM 1. NO.S OF FAN 2.
NATURE OF OPERATION
01
VF 2000 FAN 02
STAND BY FAN
MAIN FAN
3.
STAGE
02
02
4.
NO. OF BLADES
08
08
5.
BLADE ANGLE
17.5 TO 32
6.
DIAMETER OF ROTOR
1600MM
2000MM
75KW
250KW
440V & 25A
6.6KV & 32A
BELT DRIVEN
BELT DRIVEN
7. 8. 9.
0
MOTOR HP VOLT&CURRENT(MOTOR) COUPLING
0
0
0
17.5 TO 32
Air quantity at different position before and after installation of VF 2000fan at Adit 4 and Adit5
BEFORE
AFTER
ITEM Quantity handled by adit5 fan
51m /s
90m /s
Pressure developed (adit4 fan)
75 mm-wg
150 mm-wg
3
3
70m /s
3
142m /s
3
22m /s
3
100.5m /s
Qt. Handled adit4 fan
43m /s
Qt. At old arch. Room at 555m
85m /s
Qt. At intake of 555ml rd
Air quantity to 3 stage developed upto motor hp
3
51.8m /s 36.5m /s
3
3
3 3
MINING MACHINERY USED IN MINES FOR DRILLING: - AXERA DO5-126 [H] (also called jumbo or boomer)
Technical specificationso Length – 11420 mm o Width – 1750 mm Roof down = 2100 mm o Height –
Roof up = 3020 mm Turning radius 5220/2980 mm Tramming speed 12 KMPH (horizontal)
0
5 KMPH (at 8 )
Noise level <98 dB(A) Weight 11000 kg Electrical motor 45 kW (60 hp)
Boom type parallel holding 0 360 Feed roll-over Boom extension – 1200 mm Drill rod assembly length – 3.7 m Depth of hole drilled – 3.4 m Impact power – 16 kW Tyre specifications :Rubber tyres, radial type, Width to rim radius ratio : (12-20) Time taken by jumbo in drilling one 3.4 m deep hole :2.5 min (approx.) Telescopic boom of jumbo can feed up to 1700 mm. Make – Sandvik TAMROCK BOLTEC
Model
: -Boltec 235
Make
: - Atlas-Copco
Power
:-
55 kW
RPM
:-
2500
Max torque
:-
230 NM at 1550 rpm
Transmission type: Drill rod length
:-
Hole depth
:-
hydro dynamic 2.7 m 2.4 m
VARIOUS COMPRESSORS Compressor Make
No. 01 No. 02 No. 03 No. 04 K.G.Khoshla K.G.Khoshla K.G.Khoshla Atlas Copco
No. 05 Atlas Copco
Capacity
535 C.F.M
960C.F.M
Working Pressure Electric Motor
7.0kg/cm
7.0kg/cm
7.0kg/cm
7.0kg/cm
7.0kg/cm
120KW
93KW
120KW
200KW
200KW
2/3/1986
2/3/1986
21/3/1990
26/6/1998
Two Stage
Two Stage
Screw single Screw single stage stage
2
2/3/1986 Date of Commissioning Reciprocating Two Stage
535 C.F.M 2
535 C.F.M 2
960C.F.M 2
2
6600 Volts are used in this compressor.
LOADING MACHINES
Features :
Payload - 4000 Kgs Breakout force - 6700 Kgs (DIGGING) and 11890 Kgs (HYD. COMBINED) Type of engine - Deutz F6L 912W High Strength and impact resistant structure. Compact in size with short turning radius. Short loading and tramming cycles. Spacious operator compartment on rear chassis at articulation. Unique articulation joint and rear axle oscillation for minimum downtime. Full power shift Transmission. No spin on both front and rear axles. High dumping height for easy truck loading. Modulated clutch for reduced shocks and drive train stress. Pilot operated controls for reduced fatigue and increased productivity. Designed for effective maintenance. Simple 24V Electric system for ease of maintenance.
Features :
Higher payload for increased productivity. High tilt, combination and mechanical breakout force for efficient and single pass loading. Fingertip controls for reduced fatigue, higher productivity and safety of operator. High tractive efforts for working in steep gradient and single pass loading. No spin differential on both the axles. High strength and impact resistant structure. Extra large cooling system and tank capacity for lower operating temperature with HFB fluid. Option of different rating and types of bucket like bi-directional conveyor bucket. Cross seating operator position for better bi-directional visibility and safety. Simple hydraulics for ease of maintenance.
Features :
Heavy-duty gear train for low noise and trouble free operation Sturdy and rigid operator's platform for safety and ease of operation. High strength and impact resistant structure High Productivity through higher speed, large discharge angle and high hopper discharge height Low headroom permits operation in confined conditions Light machine weight permits handling and transportation Extra large bearing on gear train for longer life Box type structure of arm for higher rigidity Splined axles for ease of maintenance Spool type valves for smooth and easy operations
Features:
Dependable Rock loading Simple, self centred controls for easy and safe operation Low centre of gravity Easy swinging of upper deck for side digging Wide tread wheels with deep flanges for extra stability Power swing, as an option, for virtual pinpoint control of bucket position For operation in gradient steeper than 1 in 6, special slope loading attachments are available on model 21
DETAILS OF LAMP ROOM Lamp specificationsMake – Oldham Volts – 4 v Current – 0.8/1 amps Transformer used – auto transformer Primary volts – 400/550 volts Frequency – 50 Hz Phase – 3 DC amp – 102 amps
Lamp is issued on the basis of employee’s token number, battery number and date of issuing. It is received by time of receiving and counter-sign of employee.
PERSON ASSOCIATED: A Shift---------------------- 4 person (fitting and issuing) B Shift---------------------- 2 person (fitting and issuing) C Shift---------------------- 2 person (fitting and issuing)
LAYOUT OF LAMP ROOM
Each table has 6 racks. Each rack has a capacity of 17 lamps. Hence each table has 102 lamps.
EXPLOSIVE AND BLASTING Length of drill holes
:-
3.4m
Diameter of holes
:-
Blast hole= 45 mm
Type of explosive
:-
Emulsion explosive,cartridge form
Cartridge length/dia/weight
:-
For blasting of holes drilled by Jack-hammer drill
Length = 200 mm, Diameter = 25 mm, Weight = 125 g,
For blasting of holes drilled by Jumbo drill rig
Length = 400 mm, Diameter = 40 mm, Weight = 400 g, (approx.)
BURN CUT PATTER USED FOR DRIVES
BURN CUT PATTERN FOR RAISE DRILLING
ORE RESERVE: The gross ore reserves of Jaduguda Uranium Deposit is 10.91 million tonnes which can be classified into proved, indicated, inferred and speculative categories as follows. CATEGORIES
DEPTH
TONNAGE
GRADE (% e U3O8)
PROVED
0m to 620m.
8.48 million tonnes
0.076
INDICATED
620m to 750m
1.13 million tonnes
0.063
INFERRED
750m to 815m
0.56 million tonnes
0.063
SPECULATIVE
815m to 880m
0.74 million tonnes
0.059
TOTAL
0m to 880m
10.9 million tonnes
0.073
The distribution of ore reserve in two lodes of Jaduguda Mine is shown below.
LODE
DEPTH
TONNAGE
GRADE(% e U3O8)
FOOTWALL
0m to 880m
9.49 million tonnes
0.0745
HANGWALL
0m to 555m
1.42 million tonnes
0.0635
TOTAL
0 to 880m
10.91 million tonnes
0.073
MOINTORING AND GRADE CONTROL Uranium, Thorium and other radioactive minerals distinguish themselves from other common mineral by their physical property of radioactive decay and afford a very qu ick method of their qualitative and quantitative estimation. These radioactive substance while decaying, emit alpha, beta and gamma radiation. The alpha rays are helium atoms with two orbital electrons stripped off. Beta rays are electron and gamma rays are electron magnetic radiation’s (similar to X -rays) but of very high frequency. Uranium undergoes a series of transformation due to the emission of these rays, thereby producing isotopes of various elements called daughter products until a s table end product, LEAD, is formed. These daughter products are also radioactive. Generally all very old radioactive rocks having primary uranium contain all these daughter products in a fixed proportion to the parent i.e. uranium. Such a state is called an equilibrium state and the intensity of any of the three radiation measured is directly proportional to the parent element. This is the basic principle of all radiometric measurements. The alpha rays are very heavy ionizing particles and can hardly penetrate even paper. Hence these rays are stop by the walls of rock itself. Beta rays are slightly more penetrating, but not as much as gamma rays. Hence alpha and beta rays are unsuitable for insitu measurements. But gamma rays are highly penetrating and can even penetrate a few centimetres of lead. Thus with suitable detecting systems if the intensity of gamma radiations can be measured insitu, the data regarding the grade and thickness can be obtained in short time.
DETECTORS: GEIGER MULLER COUNTER This consists of an evacuated glass tube filled with a mixture of argon and ethyl alcohol at a low pressure. There is a wire in the centre of the tube which acts as an anode and the coaxial cylinder acts as the cathode. The application of a high voltage of the order of 1000V across the electrodes establishes an electric field. The gamma rays are intercepted by the cathode and resulting interaction produce ionization in the tube and small electrical signals are produced.
SCINTILLATION COUNTER This consists of a thallium activated sodium iodide crystal and an electronic device called photo multiplier tube. Whenever a gamma ray passes through the crystal, a part of the energy of the ray is absorbed in the crystal. This absorbed energy produces excitation in the crystal resulting in small spaces of light called scintillations. These are picked up by the photo multiplier tube, which in turn produces small electrical signals. Thus both the above detectors convert the gamma rays into small electrical signals. Since these signals are too small, they are amplified and shaped to equal amplitude pulses by means of electronic circuits. These signals can be counted directly by an instrument called scalar, or converted into a current, which is measured by a counting rate meter. Thus for any measurement, a detector, a high voltage supply and a scalar or a counting rate meter are essential.
APPLICATION IN A MINE For mining of uranium ore since it is not visible it is essential to have an idea of the thickness and grade of the mineralised portion of the rock, so that the waste cutting is reduced to minimum, thereby effectively controlling the grade. This is being done as a matter of routine in all development faces to direct the courses for the subsequent blasts and in all stop faces. The procedure consists in scanning the mine face with a directional probe. The probe consists of G.M. tube enclosed in brass housing and fixed in a semicylindrical lead shield of about 2.5 cm. Thickness. The shield enables to cut off the radiation coming from all directions except from the portion against which the probe is kept. The G.M. tube is connected to a counting rate meter. The probe consists of G.M. tube is moved at regular interval of 15 cm. along a diagonal line drawn perpendicular to the foliations. The instrument is pre calibrated in % of U308 is known, one can delineate the ore zones as per the cut off grade. Sometimes the ore body is quite wide and the HW contact is not exposed in the drive itself. In such cases, regularly spaced exploratory holes are drilled at right angles to the foliations and are logged with G.M. detector attached to a long conduit. The detector is inserted in the holes and readings are taken at regular intervals. From these readings the thickness of mineralised ore zone can be known. By plotting these readings one can easily get an idea of the profile of the ore body in various horizons. As a part of exploration work, diamond drilling is also being done at different levels. These bore holes are also logged with a G.M. tube detector housed in waterproof brass housing with a built-in pre-amplifier. The probe is also used along with a counting rate meter. In order to keep the grade of the broken ore above the particular cut off value, bulk assaying units have been installed in the main tramming levels just before the ore pass. Here the more efficient scintillation detectors are used along with a scalar. The detectors
are kept in specially designed collimated lead shield, so that the maximum area of the individual tub is looked into. The unit is calibrated to give grade in terms of % eU308. Thus one can know the grade of the material drawn from the various stopes and development points, before it is dropped into the ore pass and hoisted up by the skip for the subsequent processing in the mill. With the knowledge of the grade of the ore at the various drawing points in the different levels, the tramming schedule can be drawn judiciously to maintain the grade at some optimum level for the mill feed. Once the grade and the tonnage from various levels of the ore drawn are known, the feed for the mill is calculated every day. The mill draws a sample of the classified overflow product, and a portion of it is chemically assayed in the Control, research and development laboratory of the mill and the other portion is radio metrically assayed by us. Thus a tally of the tonnage and grade of ore supplied to the mill and the tonnage ground in the mill with the corresponding chemical U308 value of the ore is made. A month wise statement of ore ground by the mill and raised by the mine with respective grades is also made. These grades tally perfectly well with in the statistical error limit of ± .002. In order to estimate ore reserves and grade block wise for stoping purposes, channel samples are cut regularly in the underground. These samples are regularly assayed for their U308 value in the laboratory. ACCIDENTS RATE IN JADUGUDA MINE
Number of Accidents
100 90 80 70 60 50 40 30 20 10 0 2000
2001
2002
2003
2004
YEARS
2005
2006
2007