Practices and Principles Flashcards
Dilution and removal of:
Heat, Dust, Gas
Sources of Heat
- Trucks
- Loaders
- Secondary fans
- Pumps compressors
Sources of Dust
- Loading
- Tipping
- Blasting
- Roadway
Sources of Gas
- Trucks
- Blasting
- Natural gases
> methane
> sulphur dioxide
> hydrogen sulphide
Primary ventilation
Main intake airways and return airways employing shafts or declines with either axial or centrifugal fans
Secondary ventilation
Ventilation of areas where primary ventilation circuits can’t reach
Primary Ventilation requirements
- adequate shafts, declines, inclines
- large airways
- fan power
Secondary ventilation - forcing system ADV and DISADV
adv
- fresh air at the face
- max benefit to operators
- easy installation
- leakage is outwards and easily detected
Disadv
- long re-entry time
- persons travel in contaminated air
Second vent - exhaust adv/disadv
adv
- persons always travel in fresh air
- short re-entry period
Disadv
- intake air moves slowly and picks up heat, dust, fumes
- two fans and columns required
- exhaust under negative pressure requiring steel ductin
Vent appliances
- fans
- doors
- stoppings and regulators
- sprays and filters
- monitoring instruments/devices
Primary Fan types
- Axial flow
- Centrifugal (radial) flow
Main Fan fixtures (required)
- bearing fitted with temperature trips, vibration trips
- equipped with a pressure recording device
- alarmed
Main fan fixtures (optional)
- self closing doors
- anti roll back device
- water spracy
Main fan fixture (performance)
- Variable pitch blades
- Inlet guide vanes
- Variable speed
Ventilation Doors
- Designed to block airflow while allowing the passage of personnel and equipment (manually operated or automatic)
- singe door in area of low activity/low pressure
- double (airlock) doors in areas of high usage/high pressure
Stopping
- Designed to completely block airflow
- Temporary Stoppings
> frame with conveyor
> Mesh with vent bag - Permanent
> solid shotcrete/aquacrete walls
> Brick walls
Regulator
Designed to allow variable amoutns of air throught an area by increasing/decreasing the resistance of an airway
Water Sprays and Filters
- Used to reduce dust contaminating air
- used at
> intake aiways
> loading points
> tipping points
Air Quality Devices
- Anemometer
- Hygrometer
- Manometer
- Gravimetric Sampler
Vent Costs
- Fans
- Power
- Instruments
- Vent bags
- Vent appliances
