Orica - Recent Innovations in Perimeter Blasting

Recent Innovations in
Perimeter Blasting
Ontario Mining Health and Safety Conference
Sudbury – April 18, 2013
Development Blasting – Perimeter
Control
• Context
– Perimeter control refers to additional measures taken in the
outside holes of a development round to reduce the impact of
blasting on the surrounding rock mass. Good perimeter control
lowers scaling and bolting time, decreases over break and reduces
reconditioning.
• Orica HandiLoader System
• PowerGel Viper
Perimeter Control
•
The act of reducing the impact of the explosive detonation
pressure inside the borehole and on the surrounding mass.
Explosive Energy
Detonation Yields
Shock Energy + Gas Energy…
... that Breaks
and Heaves Rock
Effects on Shock Wave
6-inch diameter borehole
explosive fully coupled
Trace height indicates
intensity of shock wave
shock sensor 1m from borehole center
2-inch diameter borehole
explosive fully coupled
6-inch diameter borehole
with 2-inch diameter charge
air space around charge
6-inch diameter borehole
with 2-inch diameter charge
water in space around charge
HandiLoader String Loading System
Orica String Loading System
A combination of specific products and PLC
controlled equipment resulting in a variable
speed retraction system for the charging hose,
designed for minimising damage in the back and
side walls.
Constant pumping velocity c [kg/s]
Controlled retraction speed v [m/s]
Q = c/v [kg/m]
Bulk Emulsion Explosive
• Water in Oil Emulsion
– External oil phase is water
repelling (Water resistant)
– Water Phase
• Oxidiser Solution
– Nitrates (70-80%) + Water
(20-30%) + Minor
Chemicals
– Fuel Phase
• Readily available oils
including diesel, paraffin oil,
vegetable oils or wax’s
(Packaged)
• Emulsifiers/Chemicals
Dual Sensitized/Variable
Density
Equipment
• Emulsion Pumping
Unit.
• PLC Control Unit
• Hydraulic Hose
Handling System
• In-Basket Operator
Controls
Charging Unit Illustration
Emulsion
Water
Gassing agents
Dosage
pump
Dosage
pump
Charging
hose
Main pump
Mixing
nozzle
Instrumentation
Homogenizer
Hose Retraction
HandiLoader String Loading System
Flexible Charging Density
75 % reduction
50 % reduction
100 %
Application
Universal Explosive - Different Charging Densities
Distribution of charging densities in a typical road tunnel (45 mm drill bits):
Contour
Up to 5 preprogrammed
loading density
options
Internal Contour
Stoping a
Cut
Wall
Stoping b
Lifters
Wall
Glass Tube Loading
40mm (0.25m/sec.)
40mm (0.25m/sec)
32mm (0.40m/sec.)
32mm (0.40m/sec.)
22mm (0.83/sec.)
22mm (0.83/sec.)
HandiLoader String Loading System
Features & Advantages
Safety
Reduces peak pressure and rock over break through string charging
Reduced crack zone/damage to surrounding rock structure
No risk of pull-outs or blow-out as experienced with packaged products
Variable density
Allows to reduce energy density in hole
Allows complete flexibility of charge from 25% to 100% of hole volume
Efficiency
Shorter charge time (up to 50% less time compared to cartridge explosives
Charging documentation generated by system
Cost
Lower overall cost per round of explosives
Considerably cheaper than conventional perimeter products
Benefits Identified in Local Trials
• Compared to conventional packaged
explosives
–
–
–
–
–
–
–
–
Over-break reduction – 6% Average
Finer Fragmentation (95%<16in vs. Anfo @ 32in)
Reduced Damage to Services – 50%
Reduction in Bolting Required – 6.6%
Muck Pile Height/Profile and Cast
Cycle Time Reduction
Advance Rate – Equal or better
Explosives Cost Reduction – (13 – 24%)
Benefits Identified in Local Trials
• Compared to conventional packaged
explosives
– Post blast Ventilation Time – Reduction in
Ammonia
– Re-blasting Costs – reduced misholes
– Loading Efficiency – vs. Packaged Explosives
– Reduction of Manual Labor –vs. packaged
– Product rationalization – no need for specialized
products
– Ability to adjust powder factor and blasting
process for specific rock type
Over Break Reduction
Traced Anfo
String Loading
Fragmentation
Anfo
String Loading
Example of MacLean Loader
Conversion
Example of IFI MineCat
Boom Basket – Large Headings
Example of IFI MineCat
Man-lift– Narrow Vein – used in 10x12ft
Orica PowerGel Viper
Packaged Perimeter Control Product
PowerGel Viper
•Product aims to deliver an easy to use
perimeter control product.
•Good wall control product for a
positive impact where miners spend
~50% of their time in the scaling and
bolting cycle.
•Based on accepted Razorback
concept.
•Improved toe design
•Improved explosive formulation
•Improved retention device
•The lack of detonating cord
differentiates itself from other products
PowerGel Viper
Product
Characteristics
•Precut length – 14 ft
•Watergel explosive
formulation (Detagel)
•Density – 1.20 g/cc
•VOD – 5000 m/sec
•Toe Charge Design
PowerGel Viper
Safety
•Low impact sensitivity compared to other
perimeter control products
•Engineered detonator well
•Detonator locked in and ideally located within the
explosive charge
•Stabilization in the blasthole provided by a spider
locking device
•Highly visible
•Decoupled charge minimizes damage to back and
walls
Ease of Use
•A single pre cut piece – no assembly
•Improved priming
•One piece design
•Higher toe charge
Any
questions?