Presentation on theme: "MINE GASES n Category of Gases n Physics of Gases n Exposure Limits n Measurement of Gases n Mine Gases n Smoke & Damps."— Presentation transcript:
MINE GASES n Category of Gases n Physics of Gases n Exposure Limits n Measurement of Gases n Mine Gases n Smoke & Damps
Category of Gases n Noxious: Asphixsiant due to lack of Oxygen n Toxic: Poisonous-short or long exposure
Physics of Gases n Specific Gravity/Vapor Density: The weight of a ratio of a specific gas compared to the same ratio of air.(Air = 1.000) n Temperature: Cold gases will diffuse slowly, hot gases will diffuse quickly. n Graham's Law: The rate of diffusion, the lower the specific gravity, the faster it will diffuse. n Barometric Pressure: The lower the pressure, the faster a gas will diffuse. n Solubility: The ability to dissolve in water(taste and/or smell)
Exposure Limits n Threshold Limit Value (TLV)- The amount of a gas exposure for an 8 hour day for 5 days a week without any harmful effects. n Ceiling Limit- The amount of gas at no time a person can be exposed to. n Immediately dangerous to life or health(IDLH)- The maximum concentration of a gas, in case of SCBA failure, one could escape without any irreversible health effects.
Measurement of Gases Parts Per Million (PPM)- The most accurate measurement of a contaminant in the atmosphere. (4) PERCENT PPM , … 1, … … … 1
Mine Gases & their Components n AIR Chemical Formula: None Specific Gravity: Source: Atmosphere Characteristics: No color, odor, or taste Pure dry air at sea level contains the following: – Oxygen % – Nitrogen … % – Argon % – Carbon Dioxide %
Oxygen Chemical Formula: O 2 Specific Gravity: Oxygen will not burn or explode Source: Atmosphere Characteristics: No color, odor or taste Note: When another gas is introduced into the atmosphere of artificial environment, such as a mine, tunnel or man holes, oxygen is usually displaced causing asphyxiation.
Oxygen Present % Effect n 21% Breathing Easiest n 19.5% Minimum required by law n 17% Breathing faster & deeper n 16.25% Minimum required by law n 15% Dizziness, buzzing noise, rapid pulse, headache, blurred vision n 9% Unconsciousness n 6% Breathing stops, cardiac arrest
Noxious Gases (Explosive) n Methane Chemical Formula: CH 4 Specific gravity: Needs 12.5% O 2 to ignite Explosive Range: 5-15% Ignition Temperature: 1100 o o F Source: Carbon products decaying in anoxic environment Characteristics: No color, odor or taste Heavy Hydrocarbons (LEL) Ethane Propane Butane C 2 H 6 C 3 H 8 C 4 H % % % All have a gassy odor
Hydrocarbons (cont) n Acetylene Chemical Formula: C 2 H 2 Specific Gravity: Explosive Range: % Ignition Temperature: 581 o F Source: Methane heated in a low oxygen atmosphere Hydrogen Chemical Formula: H 2 Specific Gravity: Needs 5% oxygen to ignite Explosive Range: % Ignition temperature: 1030 o o F Source: Water on super hot fires, battery charging
Noxious Gases (Non Explosive) n Nitrogen Chemical formula: N 2 Specific Gravity: Ceiling Limit: 810,00 ppm Source: Atmosphere, released from coal seam Characteristics: No color, odor, or taste Carbon Dioxide Chemical Formula: CO 2 Specific Gravity: Ceiling Limit: 1.5% IDLH: 50,000 ppm Source: Product of complete combustion, slow oxidation of carbon products Characteristics: No color or odor, acidic taste above 10%
Toxic Gases (Explosive) n Carbon Monoxide Chemical Formula: CO Specific Gravity: Needs 6% O 2 to ignite Ignition Temperature: 1100 o F Explosive Range: % TLV: 50 ppm Ceiling Limit: 200 ppm IDLH: 1500 ppm Source: Incomplete combustion, diesels, gasoline engines Characteristics: No color, odor, or taste Effect on the body: 300 times more attracted to hemoglobin than oxygen, forms carboxyhemoglobin which prevents oxidation of cells
Toxic Gases (Explosive) cont. n Hydrogen Sulfide Chemical Formula: H 2 S Specific Gravity: Ignition Temperature: 700 o F TLV: 10 ppm Ceiling limit: 15 ppm IDLH: 300 ppm Source: Sulfur dissolving in water in a poorly ventilated area Characteristics: Colorless, sweet taste, rotten egg smell Effect on the body: Paralysis of respiratory system
Toxic Gases (Non-Explosive) n Nitrogen Dioxide Chemical Formula: NO 2 Specific Gravity: TLV: 1 ppm Ceiling Limit: 3 ppm IDLH: 50 ppm Source: Explosives after-product, diesel exhaust Characteristics: Burnt powder odor, reddish brown in high concentrations Effect on the body: Forms nitric acid in lungs causing pulmonary edema
Toxic gases(cont) n Sulfur Dioxide Chemical Formula: SO 2 Specific Gravity: Source: Burning of sulfide ores, diesel exhaust, gob fires TLV: 5 ppm Ceiling Limit: 10 ppm IDLH: 100 ppm Characteristics: Heavy sulfur odor Effect on the body: Same as nitrogen dioxide
Smoke n Tiny particles of solid and liquid matter suspended in air as a result of combustion n Diesel Particulate Matter n By-products of burning belts n Carbon materials n Usually noxious and toxic gases are present n Can be carcinogen(cancer causing)
Mine damps n The word damp is a derivative of the German word damf which means vapor. It was used by the immigrant German miners in the anthracite fields to describe a certain atmosphere condition. Black damp: Carbon dioxide, nitrogen, and low oxygen. White damp: Carbon monoxide Fire damp: Methane Stink damp: Hydrogen Sulfide After damp: By-products of a fire or explosion.