MINING METHOD

Pneumoconiosis - This is a lung discase caused by inhalation of coal dust laden air over long periods of time(Some years) When a man breathes dusty air, coal dust particles coarser than 7 micron size(1 micron =1/1000mm)are held up in the upper respiratory tract but various percentage of particles of other sizes reach the lung.Some of these cling to the lung surface forming nodules and render some area inactive.On repeated inhalation in such air over extend periods of time,more and more area is involved,causing shortness of breath and weakness.Grandually the man loses total energy to work.It renders the man prone to bronchitis and T.B.also. So far no satisfactory cure of this disease could be found.Hence the only option is prevention.As per the Mines Rules mine workers are subjected to initial and periodic (5years)medical examination,and the X-ray plates are checked to detect the disease in early stage.If necessary his work place is changed to limit the exposure to dust.Under the Mi...

  In any Under ground coal mine,even at normal temperature some oxidation of coal takes place.In this process,some O2 is consumed and CO is produced.The ratio CO produced/O2 consumed,known as Graham's Ratio or Graham's Index,for a mine remains more or less constant.If spontaneous heating occurs there is steady rise of the ratio with increase of temperature.The ratio can,therefore be used as a guide to detect heating.     Regulation prescribe that the return air of every depillaring distt.Shall be analysed at least once in every 30days to determine the Graham's Ratio.If successive tests show steady increase in the ratio,steps shall be taken to determine the site of heating and to deal with it.      Incubation period : This is the period between the time when coal is first subjected to condition favourable for heating develop when the first Major roof fall occurs, because fallen/Crushed coal starts heating but the heat does not escape as coal...

Causes of fire in open cast mines                      Major cause of fire in open cast mines is spontaneous heating.It occurs under the following circumstances: Development of cracks in exposed coal benches due to back breaks/side break on account of poor blasting. Allowing looss coal to accumulate at the toe of an idle coal face.Presence of inferior coal matter and shale in overburden dumps.Large stock of coal. Extraction of developed pillar by open cast.                                                       Other causes of fires are: Burning fire/dumping hot ashes on outcrop of coal or exposed coal. Fires in diesel and electric HEMM due to poor maintenance.Fire in disel operated HEMM while extracting blasting coal of development pillars.

Dozer : It is a diesel operated crawler chain mounted machine with a pusher blade at front for pushing loose material or for cutting soft earth.It is a very useful machine of opencast mines.                                                        Dozer is used for various job like-                      Pushing and gathering scatter blasted material for loading by shovel or pay loader. Cleaning the bench of coal/OB fallen during dumper loading by shovel.Levelling blasted OB and preparing ground for placement or dragline.Pushing and levelling material in OB or coal dump. Preparing face for placement drill. Pushing coal into ground bunker of coal handling plant(CHP).Making haul road cutting side drains and removing muck.Shafting skid mounted blasting shelter switch pump and cable in the quarry.Level...