MINING METHOD

* Flame trap or flame arrestor is used with                (1) Conveyor   (2)direct haulage  (3)diesel locomotive  (4)shaker conveyor.                                                                                                                     * The flame trap of diesel locomotive is liable to choke up due to                                                            (1)dust in air (2)impure engine oil  (3)narrow aperture of plates (4)poor filter         ...

 * Which of the following belong to hard rock mining?                                                                          (1)Potash. (2)Salt. (3)trina. (4)iron.                                                                                                   * Gravimetric dust sampler is;                              (1) intrinsically safe apparatus. (2)FLP,(3)It has both the features, (4)none of the above.                    ...

No person shall be allowed to rush to rescue the man, because he may also fall unconscious.    The Overman along with two workers of strong physique shall don self rescures and bring out the victim to fresh air.   Simultaneously arrangements shall be made to fetch stretcher and first aid box.A responsible man shall be put to infrom the manager of the mine over phone regarding the incident and to send for the rescue team.As soon as victim is brought to fresh air,artficial respiration shall be applied and continued until he recovers.If the victim has difficult recovering, resuscitation apparatus brought by the rescue team shall be put to use. Victim shall be transported to surface for medical aid.A repot of the accident shall be written at the end of shift.  

  Timber supports are heavy,bulky,costly,time consuming of short life and indefinite strength and use of timber has in volved cutting trees.Therefore they have been replaced by steel supports to a large extent.They are still used in many situations for example -Cogs at goaf edges and junctions.Two cross bars on cogs at roof ledges.Vertical props with lagging at pillar side having tendency to spall. Inclined stay props to support overhangs.Support of faults slips break in roof by cogs on either side with cross bars across them.Supports of isolated spots in roadways by props,cross bars or cogs as required.As temporary supperts.                                                                     

Haulroad: Type of haulroad has a profound influence on operation of the mine,it is life line of an open cast mine.                                                                                                                                  Benefits of a good haulroad: (a)High production because of increased dumper speed.       (b)Better safety.     (C) Reduction in maintenance and less machine breakdowns.    (D) Saving in diesel,tyres,spares. (E)Lesser operator fatigue,high morale.                                        ...

All parts of suspension gear in regular use shall unless otherwise permitted by the chief inspector be renewed after a period of service of not more than ten years and at shorter interval if necessary.All cage chains in general use and all other parts of suspension gear between the rope and the cage or other means of conveyance including the detaching hok shall be taken part,cleaned and carefully examined as to wear and tear and for rust and cracks once at least in every six months,or if necessary at shorter intervals.                                                                                Every  detaching bell or plate used in connection with a safety hook shall be examined and the opening therein checked by calipers or gauges once at least in every 30days.The Oper...

Holes which are not blasted on the day when they are loaded are known as sleeping holes.; holes loaded with explosive are potentially dangerous and must be blasted at the earliest.However in large,in large open cast mines sleeping of holes cannot be avoided as very large blasts are conducted involving a large number of holes which take more than a day to load.sometimes after loading the holes the nearby equipment cannot be withdrawn to a safe place because of their breakdown and before charged holes remain in blasted for a day or mine.

The case of a mine having an average monthly output in excess of 15000tonnes,a first class manager certificate,in case of a mine having an average monthly output in excess of 10000tonnes,bot not exceeding 15000tonnes a first or second class manager certificate;in the case of a mine having an average monthly output in excess of 5000tonnes but not exceeding 10000tonnes.A first or second class Managers Certificate or a degree or diploma in mining or mining engineering approved for the purpose of the provisio to sub regulations (1)of regulations 16:।                                  Provided that where special conditions exist,the chief inspector may by order in writing and subject to such conditions as he may specify therein,a permit or require the appointment of a safety officer in variance of these provisions,Provided that where special conditions exist the chief Inspector is of the opinion thatdue to th...

          When the aim of blasting is to get 1umpy coal or to minimise the formation of coal dust then this blasting is done.in this blasting low density high Explosive are used.                                                                                  In this blasting the hole is first charged with Explosive.The Explosive charge is pushed into the holes followed by one or two piastic air bags.Remaining length of the hole is stemmed by stemming material.in it air bags work as cushion blasting.Such blasting with air gap is known as cushion blasting.

No machinery shall be operated otherwise thanby or under constant supervision of a competent person.In a gassy seam of second or third degree no person shall be appointed to supervise or operate any electrical machinery, apparatus or appliance unless he holds a gas testing certificate.every such person shall be provided with the carry an approved flame safety lamp while on duty.Every person in charge of any machinery or appliance shall,before commencing work,see that it is in proper working order,and if he observes any defect therin he shall immediately report that fact the manger,engineer or other competent person.                                                                                                      Every per...

On devlopment of spontaneous heating in the goaf, a peculiar oily, sweetish or petrolly smell is found in the return airway,on getting such a smell,the following steps will be taken., send information to:overman mining sirdar of the other districts to withdraw men to surface,the surface, particularly the manager,any senior official who may present u.g. whenever possible,the information shall be given over telephone.                                                          Withdraw men from the mine,and send them out through in take air ways and downcast shaft,without creating chaotic conditions keeping underground only the minimum person who may be required for dealing with the fire e.g.line mistris and helpers,timber man and helper,mazdoors etc.Cut off electrical power of the district.Engage men retained u.g.in preparatory works fo...

No person shall be admited as a candidate at any examination for sirdar or Shotfirer certificate unless the board is satisfied that he has had practical experience and training in a coal mine for a period of not less than three and two year respectively.Provide that in the case of a candidate for shotfirer certificate such practical experience and training shall include experience and training in connection with shotfirer for a period of at least six month. Provided further that such period shall be reduced ta a period of one year in the case of candidates who has received a diploma or certificate in scientific and mining training after a course of at least two years at an educational institutions aproved in that behalf by the Central Government or who has taken a degree in scientific and mining subjects at a university approved in this be half by the Central Government.

Original certificate has to be submitted.DGMS may allow the candidate on the basics of provisional First Aid Certificate but he will not be allowed to apper in the exam un less valid orginal certificate is submitted on or before the date of examination.

No auxiliary fan shall be started, stopped, removed, replaced or in any way altered or interfered with,except by or on the authority of an official.,No person shall enter or remain in any place which is dependent for its ventilation on an auxiliary fan,unless such fan is operating efficiency.Whenever the ventilation of any such place has been interrupted,whether by the stoppage of the fan or otherwise,no person shall so enter or remain their in except for the propose of restoring the ventilation or unless the place has been examined by a competent person and declared safe. Every auxiliary fan: shall be installed,located,and worked in such a manner that; a sufficient quantity of air shall,at all times,reach it so as to ensure that it does not recirulate air and there is no risk of the air which it circulates being contaminated by any substantial quantity of inflammable or noxious gases or dust.Shall have an air duct for conducting the air to or from the face or b...

The intake air shall be so arranged as to trvel away from all stagnant water.In every firey seam or gassy seam of the second or third degree,for every ventilating district there shall be provided two main in take airways one of which shall be used as a traveling roadways.For the propose of ventilation,every mine shall be divided in to such number of districts or splits as to ensure that separates current of fresh air is made available in every such district or split.Provided that if the regional inspector is satisfied that compliance with this regulations is not responsible practicable,he may by an order in writing and subject to such conditions as he may specify therein,grant exemption from the provisions therof

The prop may buckle or break in the middle or at a weak point in its length.A prop in the working area on being tapped with a stick gives a dull and dummy sound.Lid over the prop may bend..If floor is shoft,the prop may penetrate it. There may be rumbling sound in the goaf.make gas in the face may increase.Dust may fall from the roof crack due to grinding of strata.An existing small crack in the roof may extend or widen.

LMD is a gas detector disigned to continuously measure CH4 connection in the range of 0-3%automatically.It is hung near the face or at a strategic place.When CH4 exceed the preset value.,It gives an audio visual alarm-a buzzer and a flashing light,and being electrically interlocked,it cuts off power supply to the district.DGMS has directed to provide LMDs in degree IIANDIII gasy seams at the following places- Continuous miner face/district,On return side of longwall face,In return airway in which electric moters run,In main return airway of the mine. With change in face operation (cutting,drilling,blasting) variation in quantity of intake air of the district and change in barometric pressure,CH4 concentration in air keeps on changing.LMD provides saftey by automatic detection and warning.

Regulations require isloation stopping to be inspected by overman atleast once in every 7days.But inspection may have to be done at shorter intervals in case of thick seam,or where stopping is likely to get disturbed and leak due to strata movement.In many case,such as when fire inside is in critical state or the stopping are near a shaft and vital for safety of the mine, stopping are inspected even daily.      Items to be inspected:-  General condition of the stopping, Looseness of plastic by striking a stick against it, Cracks in and around to the stopping.checks will be made particularly at corners,joint with roof,floor and side,around the fitting.Cracks may be indicated by soot marks on the plaster.For this stopping should be kept well white washed.Cracks in the surrounding strata or any signs of weighting on the pillar.Presence of CO,blackdamp and methane using safety lamp,methanometer multi gas detector.Value of sampling pipe operable and properly close,No bloc...

 Mine wil be developed in panels. Barrier between two panels shall be one pillar thicks.Height of any gallery at any place shall not exceed 3m and the witdh shall not exceed 4.8m.For mechanised mining,DGMS may permit larger width.Size of pillar shall depend on depth from surface and width of the gallery.Minimum pilar size is prescribed in the regulations.Normally  pillars shall rectangular in shape.No narrow main or advance heading shall be driven more than 3m ahead of the widened gallery.Seam shall not be developed by ug method where hard cover over the seam is less than 7.5.If hard cover is more than 7.5m but less than 15m, development shall be done with permission from DGMS.No warking shall be made within a distance equal to half the pillar size,for the depth from surface and a gallery width of 4.8m,from the the boundry of mine so that two adjacent mines have a barrier of one pillar. Where work is done in more than one seam,barriers at the boundary shall,as far ...

According to method of mining,coal mines are of two types.Open cast mine and  Underground mines.                             Open cast mine:-  In  opencast method,soil and rock lying over small area of the coal seam is blasted,excavated and dumped on no coal bearing surface nearby.The exposed coal is blasted and mined. Operation of removal of overburden and extraction of coal continue.After coal has been removed over a large area,the over burden is dumped in the trench formed by removal of coal.This is called "backfilling".   O verburden is excavated in steps called benches for reasons of saftey and ease of extraction.Coal seam is also extracted in more than one bench if it is thick.Bench are approached by wide road ways called haul roads, because they are used for transporting or hauling of overburden or coal.        Underground mine:- Where the coa...

In coal mines,the work of cleaning of coal dust and treatment of roadways by stone dust or water is dune under supervision of a competent person, as `Dust Incharge`.For appointment as dust incharge the person should be a holder of managers or overmans certificate or s degree or diploma in mining.He is not given duties of sampling,nor is he given duties other than those of a Dust Incharge.However,in mines producing less than 5000 tones of coal per month,Dust Incharge can act as sampling incharge also.

Alomost 15% of fatal accidents in underground mines are due to haulage.The main cause: (a) Runaway of tubs. (B)Derailment of tubs. (C)Non provisions or non functioning of stop block, runway switch,drag or other safety device.(D)Badly laid curves requiring the trammer to stand on tub buffer to guide it across the curve.(E)Riding on tub buffers.(F) Failure of persons to take proper shelter in manholes,or manholes not clean and free from obstruction.(G)Uncontrolled movement of tubs.(H)Head of trammer getting crushed between tubs while coupling/un coupling.(I)Substandard sprages or shortage of sprages (J) Travelling along houlage road ways.(K)Loaders crowding at junction of haulage roadways and tramming levels to stake the first claim on empty tube.

  The over man shall have responsible charge and control of his district,carry out duties assigned by the manager and make inspection and write report required by the regulations.He shall carry a tracing of the district under his charge and keep it updated.                                                                   To ensure proper warking,saftey and discipline,he shall #enforce provisions of Regulations.*implement directives of manager and senior officials,and keep control overman. For this,he shall- ( A)Monitor work of officials and competent person(.B)-Give necessary direction,( c)-Make inspection , particularly to chek that:Supplies(timber,brattice, stemming material,roof bolts etc)are sufficient and kept in convenient places. VENTILATION :divice are maintained in good order, ventilation is adequate (bra...

To get Dust plan made by the survyor(scale 1:2000) showing- Areas naturally wet * Areas requiring stone dusting at 24 hours,7/14/30 days/3 month interval.  Areas requiring treatment with water,Keeping the plan updated.To mark the above zone u g by hanging number plate.To unsure proper stone dusting in areas required to be stone dusted.                                                               Dust on floor/roof/side/supports/structure should always contain not less than 75%of incombustible matter.If volatile matter of coal is more than 30%, incombustible content shall be not less than 85%. Before spreading stone dust,all coal dust shall be cleaned and removed to surface within 24hours.To ensure proper water spraying in areas to be treated with Water.Dust in charge shall be that within 90m of the face spraying...

These are two type:-  a)- Low tension detonator (b) High tension detonator(not used in mining).                                                ORDINARY electric detonator ore of instantaneous type ie.without only delay element.The priming charge and base charge are the same as plane detonator ie.ASA as prime change and PETN as  base charge.They are not fired by ignition or sefty fuse  but by passing electric current through a fuse head.The resistant of low tension detonator aith a 45meter long short firing cable is about 7π.Current required for igination of the fuse head is 0.5amp.and single detonator can be blasted with minimum voltage of 3.5volts. The continuity of circuit of LT detontory is tested by galvanometer.

Hydraulic stowing can not effective in the case of flat and shallow seam,at this case hand packing preferable. Hydraulic stowing is used where the mines situated within the 15km.from the river.1.3tonne of sand required for one tone of coal extraction from vergin area.2.5 tones of sand is required for every tone of coal extraction from old working.1.8ton of sand is required for every tonne of coal extracted from depillaring.1.4te.of sand required for every tonne of coal in L/W asvancing.In the shaft the showing pipe is supported on stell pipe placed every 30 to 40mm.size For one tonne of sand required 1.5to2tones of water for stowing propose.For 1tone sand required 935 to 1100lit water for stowing propose.Explosed roof are not are more than80m square at working place in the stowing practice.In stowing mixing chamber provide kent velocity meter or v.notch or venturi meter for measurement of water and leo recorder is provied for sand measurement.

Liquid oxygen explosive shall not be used in u/g.Only catridge from explosive should used in mines.NO container shall contain 5kg of explosive and person not more carry than1 container. Provide that by order of CI larger quantity of explosive shall be carried in a single container.For solid blasting in coal$for drivage though rock permission to carry more than5kg explosive.At the reserve station the container shall be not less than10meter.apart of detontor also keep not less than 10m.away from the expive container.No person other than shot firer and also helper should be present with in a distance of 10m.Where priming is done.The explosive in bunk shall be transported to the site of blasting not more than 30min,before the commencement of charging the hole.Not more than200detontor are transported in a vehicle at a time. Explosive vehicle marked with the world Explosive in red letters not less than 25cm on a white background. Explosive vehicle shall not be driven at a speed exceeding 25k...

  Opencast working--In open cast working,the following precautions shall be observed,namely:                                          In alluvial soil,morum,gravel,clay,debris or other similar ground-;*the side shall be sloped at an angle of sefty not exceeding 45degree from the horizontal or such other angle as the regional inspector may permit by an order in writing are subject to such conditions as he may specify therein;or the side shall be kept benched and the hight of any bench shall not exceed 1.5meter and the breadth thereof shall not be less than the height:।       Provide that the regional inspector may,be an order in writing and subject to such conditions as he may specify therein, exempt form the operation of his clause any working in the case of which special difficult exist,which in his opinion make compily with the provisions their ...

Highwall mining is a method of extracting coal from highwall of an open cast mine by driving galleries in the coal seam using remotely operated high wall miner.                                    The  method is used when opencast mine reaches a limit beyond which coal extraction is not possible due to economic reasons or due to economic reasons or due to local surface constraints (papulated area or surface structure).            Method :-Base unit of HW miner(length17m, width 10m,height 8m)is set on the bench in front of the highwall.It's remotely operated cutter head, similar to the cutter head of cotinous miner used underground,cut a gallery(entry)in coal.Coal then falls in a short belt conveyor for dumping it behind or to one side of the bese unit tor further transport by payloader/trucks.                ...

In simulation electric blaSting a misfire may be due tu:- Defective expider,detontor or explosive inself.Broken leading wires,broken blasting cable bad connection between exploder and blasting cable, bad connection between blasting cable and leaking wear.Short circuit of blasting cable and leading  wire due to bad connection.

It is sudden explosion of air from decoaled area at high speed causing damage of mine property and enjury to person. Air blast is associated with:- When the expose roof is very large.If the roof is massive sand stone (Alitimate crushing strength is very high)If the imidiate roof is of shale.When thick seam mining is practiced.

 The lower strata of immediate roof separate and fall in the goaf.The fall which takes place soon after whithdrawal of supports is called "local fall".The local fall takes place within24 to 48 hours of the withdrawal of timber.such a local fall does not extend to the surface.

When the area of extraction or void area is nearly eqal to or more than the square of the depth,the cracks due to depillaring extend up to surface.The rooffall which affected the surface is known as"Main fall".The main fall take place long after the first roof fall or localfall in the depillaring district. If the seam is at a shallow depth the air leaks through the cracks which is developed due to main fall and is responsible for spontaneous heating.Such spontaneous heating hass been the case of fire in the area near Jharia and Katras town.

A CCM cut groove 1m to 2.5m in depth and125 to175mm.in height at a coalface.The length of jib in CCM is1to2.5m.The chain speed in ccm120to170mm/min.and cutting speed 0.3 to1.5m/min.*The total no of pick on jib are 35 to90depending upon to the length of jib.For any crawler mounted machine the sufficient gradient 1in4.*Face machine used in below ground:- Coal cutting machine,Drill,Shearers,Coal plough,Contionues miner,,Road header,Mechanical loader,Roof suporting machine,Water infusion pumps,Face pumps,Transport machine.@Classification of CCM based on cut position:-"Under cut CCM based on cut(if cut given on the floor level) Middle cut CCM(if cut is given between roof and floor)Over cut CCM(if the cut is given at the roof level)"@Classification ofCCMbased on there design and application:-Shot  wall CCm,Long wall CCM,Bent jib CCM,Arc wall CCM,Arc shearing CCM *.Coal cuting machine is used in mine to gent necessary free face.

 Every competent person shall be subject to order of superior officials,and shall not#deputy another person to perform his work without the sanction of his superior official.*absent him self with out having previously obtained permission from such official for the torm of his absence or without having been relieved by a duly COMPETENT person and without permission from such offical perfrom during his shift any duty other than those for which he has been appointed.

  Generally Weight of the rock in coal mining area exerts a pressure of nearly 0.2kg/cm2 for every meter depth from the surface.Rocks are called massive when bedding planes are the 75mm to1.2meter and rock called fluggy when bedding planes less than 75mm.When working and driving road way the immediate roof called about 6m.above the seam and immediate fllor some 3m.*below the seam.Angle of draw-It is the angle between the vertical and final line of break. Comprehensive or crushing strength of coal many consider 2.25kg/mm2or1.5ton/sq inch. Comprehensive strength of sand stone is nearly13.5kg/mm2.Best rrof called in stone(eg-Girdhi Coal Fields).Shale roof is unrelible.0.6meter of coal intact near ashaly roof during development of mine.

Open cast mining also called open pit mining, open cut mining surface mining and also strip mining.In manual quarrying the hole made1.2m.to1.8m long and dia.37mm.In mecahanised mining hole made 6to18m.long and125mm.to250mm.diameter. PLACER MINING - in this mining the mining and wasing to gethor of generally unconsolidated or semi consolidated rock near the ground surface and the method is normally not treated as o/c mining but variation of folt.

Incubation period varies between 3months to 10months for Indian coal seam*No of pillar in a panel system is kept 12to30*Maximum barrier should be kept in pannel system in 20metor*Bucket capacity of SDL is0.6m3*Bucket capacity of LHDis1.5m3.The parting between to seams less than 9m,this seam is known as contiguous seam.*Endless rope houlage work up to distance600m,along the strike.Belt conveyor work up to 1000m,distance along the strike.Chain conveyor works100m, distance in the level and dip. Direction and 70m distance inthe direction of rise side.If roof consist of shale,0.6m thik ness coal left intact in the roof.