ISMR Technology Transfer Seminar

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ISMRTechnology Transfer Seminar

• ANFO Emulsion Characteristics
• Heavy Blends as a Tool for Blasters!

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What is needed for an explosion?
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ANFO

• Ammonium Nitrate / Fuel Oil
• Ammonium Nitrate Production
• Reaction of anhydrous ammonia gas and
  concentrated nitric acid.
• After the reaction the AN solution is about 83
  concentration.
• Excess water is evaporated off to leave an AN
  concentration of 95 to 99.9.

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AN Production contd

• AN Solution is turned into prill.
• A small percentage of water is left in the
  solution when the prill is formed.
• When the prill is dried the water is removed and
  it leaves voids in the prill.
• This is where the diesel fuel goes when added to
  the prill.

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ANFO Characteristics

• ANFO Density ranges from .82 - .90 g/cc
• Oxygen Balanced _at_ 94.4 AN / 5.6 Fuel
• Under fueling leads to
• Greater sensitivity.
• Drastic loss of ENERGY!
• Orange smoke, inefficient reaction during
  detonation.
• Over fueling leads to
• Loss of Energy.

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Effects of Fueling on Fume Production
http//www.cdc.gov/niosh/mining/pubs/pdfs/faafp.pd
f
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Effects of Fueling on Fume Production
http//www.cdc.gov/niosh/mining/pubs/pdfs/faafp.pd
f
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Effects of Fueling on Energy Output
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ANFO and VOD

• ANFO VOD increases as the borehole diameter
  increases.

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ANFO Characteristics

• The critical diameter of poured ANFO is about 2.0
  2.5 inches.
• Under this it will not detonate.
• If it is loaded pneumatically the critical
  diameter can be increased to 1.0 inch.
• ANFO is considered a Blasting Agent
• This means it cannot be detonated with a 8
  strength detonator when unconfined.
• It requires a primer assembly to be initiated.

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ANFO Characteristics

• When ANFO detonates it does so inefficiently.
• This produces excess gases from the reaction.
• This is a benefit to blasting due to the rapid
  expansion of the gases out into the formation
  creating a heave effect.
• This heave effect allows for easier digging.

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ANFO Characteristics

• ANFO is not waterproof or even resistant.
• ANFO can deflagrate if a significant amount of
  water has damaged the ANFO.
• ANFO can fail to detonate if water has damaged
  enough ANFO in the hole.
• If the ANFO shoots low order, it shoots
  inefficiently and produces excess gases.
• Orange fumes!

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Emulsion

• Water solutions of oxidizers in an oil medium.
  (ISEE Blasters Handbook Chapter 7, page 77.)

• A mixture of two or more liquids in which one is
  present as droplets, of microscopic size,
  distributed throughout the other.

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Explosive Emulsion Anatomy

• Oil continuous, external phase (green) 5 to
  9
• Mineral oils
• Diesel fuels
• Recycled oils
• Vegetable oils
• Aqueous salt discontinuous, internal phase
  (blue) 91 to 95
• Ammonium Nitrate
• Calcium Nitrate
• Sodium Nitrate
• Perchlorates

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Bulk Emulsion Characteristics

• Typical density of a sensitized emulsion runs
  about 1.25 g/cc.
• Loaded in diameters between 1and 12 inches.
• VOD increases with Borehole Diameter.
• Sensitivity/density can vary with the addition of
  microballoons or chemical gassification.
• Can be dead pressed when sensitized with
  microballoons. (Crushing of balloons)
• Can be classified as Oxidizer of Blasting Agent.

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What are Heavy Blends?

• Blends of ANFO and Emulsion

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Heavy ANFO Blends

• Why utilize blends?
• Increase the density of ANFO hence, increase
  energy in the borehole
• Provide water resistance to ANFO
• Reduce mining costs
• (ISEE Blasters Handbook Chapter 9, page 93.)

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Heavy ANFO Blends
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Emulsion/Blend Properties
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Emulsion/Blend Properties
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Generic Cost Comparison
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Blend Benefits

• Longer sleep times with heavy blends.
• Water resistance for ANFO in wet formations.
• Pattern expansions.
• Maximize energy in hole.
• Drill cost savings potential.
• More production yards per hole.
• Less shots per cut.

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ANFO Shot
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Gassed Emulsion
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Gassed Emulsion
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Blend Shot
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Blend Shot
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Blend Shot
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Blend Shot