3rd PPT Mine Vent Terms

Prevention

a. Proper procedure in blasting - only explosives with fumes classified as fair or good should be used U/G. Proper stemming is essential to reduce gases.

Because of the serious gas ignition hazard, the Bureau of Mines and most

stakes prohibit the use of block powder in coal mines. Blasting off shifts or at

restricted times.

b.  Adjustment and Maintenance of I-C engines.

 c. Avoidance of open flames, fires, etc.

Removal

a.  Through a local exhaust vent system in long development headings to supply

fresh air and remove blasting gases.

a. Drainage in advance of mining (for coal mining)

b.  Drainage by bleeder entries (for coal mining)

c.  Local exhaust ventilation

Absorption

 chemical reaction in I- C engine conditioner

3 Control of Gases Underground (PRA)

Prevention

Removal

Absorption

Dust

are minute particles resulting to man-made activities, blasting, excavations,

construction, etc.

 Pulmonary Dust/ Fibro Genic Dust (harmful to respiratory system)

silica

 silicates (asbestos, talc, mica, sillimanak)

 metal fumes

 beryllium ores

 iron ores (some)

 carborundum

coal (anthracite, bituminous)

Toxic Dust (poisonous to body organs, tissue, etc.)

Ores of beryllium, arsenic, lead, uranium, radium, chromium, mercury, cadmium,antimony, manganese, tungsten, nickel

Radioactive Dust (injurious because of radiation)

Ores of uranium, radium, thorium

Explosive Dust (combustible)

 Metallic dust (Mn, Al, Zn, Sn, Fe

 Coal (bituminous, lignite)

 Sulfide ores

 Inert Dust

(no harmful effect)

Carcinogenic Dusts

Radon Daughters, Asbestos, Arsenic

SILICOSIS.

Harmful dust causes degeneration of the cells and the alveolar walls

becomes thickened and the formation of fibrous modules in the lungs causes

Phagocytes

are body cell that has the power to ingest dust. The size of 7 micros (a micron 1/1000 of an mm) in diameter, dust is considered dangerous.

Methods of Collecting Dust:

1. Acid Filter

2. 2.  Electrostatic Dust and Fume Sampler

   3.  Thermal Precipitator

   4.  Scrubbers

   5.  Individual Respirators

High power Microscope or Micro-projector & Screen

Instrument to Measure Dust

Preventing Dust

Eliminate all forms of dry drilling

 Sprinkle dusty place with water

 Suitable air currents

 Use of dust protection apparatus

 Install air/water blast to operate during blasting, mucking & dumping

operations

Adiabatic compression (geothermal gradient) 

where an increase in temperature of air of about 5.3 °F/1, 000 ft (1 °C/100 m) of depth traversed.

Reducing Mine U/G Temperature:

1. Refirgeration (Surface Cooling Plant)

2. Devaporized Compressed Air

3. Spray Tower for Cooling Water on Surface

  Refrigeration (Surface cooling plant) 

air is sent to cooling coils in the mines. Allowable air ventilation is cooled to 65 °F saturated and temperature of mine workings been reduced from 83 - 86° (dry-wet bulb) to 80° dry bulb and 78°
wet bulb.

Devaporized Compressed Air 

compressed air from the surface is sent to U/G through pipes/canvass to maximum distance of 1, 200 ft and its temperature rise to 24 °F below zero. The cold air is then mixed with warm air to cool the mine.

Spray Tower for Cooling Water on Surface

air is sent to cooling coils in the mines. Allowable air ventilation is cooled to 65 °F saturated and temperature of mine workings been reduced from 83 - 86° (dry-wet bulb) to 80° dry bulb and 78° wet bulb.

HUMIDITY

- Is the moisture content in the air. Humid air is air containing water vapor up to the saturation point. For every temperature, there is corresponding pressure of the gas at which condensation occurs. Air condenses at high pressure and low temperatures.