Mine Gases Atmospheric Testing C.4. Contributed by: Richard Black Industrial Scientific Corp.

What is AIR?? u Nitrogen (N 2 ) 78% u Oxygen (O 2 ) 21% u All other gases 1% u Total 100%

Definitions uLEL: Lower Explosive Limit - % LEL uPPM: Parts Per Million - toxic gas measurement PEL: Permissible Exposure Limit - 8 hr/day - 40 hrs/wk - (OSHA) uTWA: Time Weighted Average - 8hr/day- (ACGIH) uSTEL: Short Term Exposure Limit - 15 mins/4x shift - (w/ 1 hr break - ACGIH) uIDLH: Immediately Dangerous to Life and Health 30 mins - (NIOSH)

TOP MIDDLE BOTTOM Where will the gases be? Lighter than air: MethaneAcetylene Carbon monoxide (slightly) Heavier than air: Hydrogen sulfide Nitrogen dioxide Nitric oxide Carbon dioxide Atmospheric Testing

u Combustible Gas - Methane u Oxygen - Normal 21% u Low limit 19.5% u High limit 23.5% u Toxic gases - Measured in ppm - 10,000ppm=1% u Carbon monoxide u Nitrogen dioxide u Nitric oxide u Hydrogen sulfide

Fire Triangle Approved Gas Instruments: fueloxygen source of ignition detect the combustible gas (fuel) detect oxygen level (air) are intrinsically safe (not source of ignition) COMBUSTIBLE ATMOSPHERES

CombustibleLEL Methane (natural gas)5.0% vol Propane2.1% vol Pentane (gasoline)1.4% vol Butane1.9% vol Hexane1.2% vol Methanol6.0% vol Hydrogen4.0% vol Common Combustibles COMBUSTIBLE ATMOSPHERES

100% LEL UEL % Vol Example of Combustion (Fire damp) Methane (CH 4 ) Too Lean to Burn Explosive Mixture Too Rich to Burn

Oxygen Deficiency Risk of asphyxiation Caused by Consumption fire people oxidation decomposition Displacement humidity other gases Oxygen 19.5%

Oxygen Enrichment u Serious fire hazard u Materials burn much more rapidly u Caused by u leaking valves u leaking cylinders Oxygen 23.5%

Effects of Oxygen u 23.5%Maximum safe level (OSHA, MSHA) u 21.0%Oxygen content in Air (20.954%) u 19.5%Minimum safe level (OSHA, MSHA) u 17.0%Impairment of judgement begins u 16.0%First signs of Anoxia u 16-12%Breathing and pulse rate increase, coordination is impaired

Effects of Oxygen u 14-10% Fatigue, disturbed respiration u 10-6%Nausea and vomiting, inability to move freely and loss of consciousness u <6%Convulsive movements and gasping respiration occurs; respiration stops/minutes later heart action ceases u 3-5%Life expectancy; minutes

TOXIC GASES TOXIC GASES

Toxic Gases u Pose a threat to human life - react in the body in a poisonous fashion u Enter the body through various ways, they can be ingested, injected, inhaled or absorbed through the skin u Can react with different body systems u Often colorless and odorless

Toxic Gases u Measured in parts per million (ppm) u 10,000ppm = 1.0 % by volume u Exposure risks depend on two factors u Concentration (ppm) u Time exposed

Carbon Monoxide Data u CO: Colorless, odorless, tasteless, byproduct of incomplete combustion u Hazard: Flammable, LEL 12.6% – UEL 74% u Health: Very Toxic (can be absorbed time faster than oxygen by the hemoglobin) u Exposures:PEL/TWA50ppm (action level) STEL 400 ppm IDLH 1200 ppm u Causes: fire, blasting, gas and diesel engines u Specific Gravity = 0.967

Effects of CO u 50ppmPEL/TWA, Action level (MSHA) u 400ppm Frontal headache in 2-3 hrs u 1600ppm Headache and nausea 20 mins Collapse and death in 1-2 hrs u 6400ppm Headache, dizziness in 1-2 mins, unconsciousness and death in mins

u H 2 S: Colorless, Rotten egg smell u Hazard: Flammable, LEL 4.0% - UEL 46% u Health: Extremely Toxic, appears naturally from decomposition, reacts with the enzymes in the blood - inhibits cell respiration u Exposure:PEL/TWA 10ppm (action level) STEL15ppm u Causes: Groundwater in shaft u Specific Gravity = 1.2 Hydrogen Sulfide Data

Effects of H 2 S u. u.13ppm - Minimal perceptible odor u 10ppm - PEL,TWA, Action level (MSHA) Beginning of eye irritation u 100ppm - Coughing, eye irritation, loss of sense of smell after 2-5 minutes u 500ppm - Loss of consciousness and possible death 30 mins - 1 hr

Nitrogen Dioxide Data u NO 2 : yellowish-brown gas with a pungent odor u Hazard: will not explode u Health: Extremely toxic u Exposures: PEL/TWA 3ppm STEL 5ppm u Causes: Blasting, diesel powered equipment u Specific Gravity = 1.6

Effects of NO 2 u 3ppm - PEL/TWA u 5ppm - STEL, Action level (MSHA) u 20ppm - Irritation of eyes, nose and throat ** u 50ppm - Maximum exposure for a 30 mins u 200ppm - Tightness of chest, acute bronchitis, and death in prolonged exposure High doses can cause pulmonary edema - drown from inside out ** Nitric Acid = NO 2 + H 2 O

Nitric Oxide Data u NO: Colorless gas, typically formed when air is super heated and nitric compound like dynamite explode u Hazards: will not burn, will accelerate burning u Health: extremely toxic –Exposure limit: PEL/TWA 25ppm (action level) STELN/A u Causes: Blasting, diesel powered equipment u Specific Gravity = 1.6

Effects of NO u 0-50ppm -irritation of mucus membranes u 25ppm - PEL/TWA, Action level (MSHA) u ppm -Irritation is more intense, coughing and burning of the throat is evident, symptoms will clear if victim is removed quickly to clean air. u ppm -May be fatal even after very short exposures.

Sulfur Dioxide Data u SO 2 : Colorless gas, irritating pungent odor u Hazards: will not explode, can combine with water to form sulfuric acid (H2SO4) u Health: extremely toxic u Exposures:PEL/TWA2ppm STEL5ppm u Source: Hardrock mine strata u Specific Gravity = 2.2

Effects of SO 2 u.3-1ppm - Initially detected by taste u 2ppm - PEL/TWA u 5ppm - STEL u 20ppm - Irritation of nose, throat and eyes ** u 100ppm - Maximum exposure for 30 mins ** Sulfuric Acid (H 2 SO 4 ) = SO 2 + H 2 O

Hydrogen Cyanide Data u HCN: Colorless to a pale blue gas u Hazard : will explode - LEL 5.6% - UEL 40% u Health: extremely toxic, has a distinct odor resembling bitter almonds u Exposures:PEL/TWA 10ppm STELN/A u Sources: Leaching of precious metals, Metal mining u Specific Gravity = 0.69

Effects of HCN u 10ppm Permissible Exposure Limit u 5-10ppm Headache, dizziness, unsteadiness u ppm Feeling of suffocation, nausea u ppm Death from exposure in 30 to 60 minutes

Ammonia Data u NH 3 : colorless gas with a suffocating odor u Hazards: Difficult to burn, LEL 15% - UEL 28% u Health: extremely toxic u Exposures: PEL/TWA25ppm STEL35ppm

Effects of NH 3 u 0-25ppm -Minor irritation of the eyes and respiratory tract u 25ppm -PEL/TWA u ppm -Swelling of the eyelids, conjunctivitis, vomiting, irritation of the throat u ppm -Very dangerous concentrations, death from prolonged exposure

Carbon Dioxide Data u CO 2 : byproduct of complete combustion, present in the atmosphere (about 400ppm), acidic taste u Hazard : Non-flammable u Health: simple asphyxiant u Exposures:PEL/TWA 5000 ppm STEL30,000 ppm u Causes: Combustion, respiration, decomposition u Specific Gravity = 1.5

Effects of CO 2 u 400ppm -Approx.. ambient level u 3,000-5,000ppm -Low concentrations cause increased respiration and headaches u 8,000-12,000ppm -Headache, nausea, vomiting, and if not given air or oxygen, possible unconsciousness u >15,000ppm -High concentrations cause rapid circulatory insufficiency leading to coma and death

Review Questions (Answers on the next slide) 1. What gas is the most plentiful in normal air? a. Nitrogen b. Oxygen c. Carbon dioxide d. none of the above 2. How much methane is required for an explosion to occur? a. 5% - 15% b. 15% - 20% c. 5% - 75% d. 10% - 100% 3. Which of the following gases are produced in diesel engine exhaust? a. Nitrogen dioxide b. Nitric oxide c. Carbon monoxide d. all of the above 4. Which of the following gases is heavier than air? a. Methane b. Acetylene c. Hydrogen Sulfide d. None of the above

Answers to Review Questions 1. What gas is the most plentiful in normal air? a. Nitrogen 2. How much methane is required for an explosion to occur? a. 5% - 15% 3. Which of the following gases are produced in diesel engine exhaust? d. all of the above 4. Which of the following gases is heavier than air? c. Hydrogen Sulfide