Underground Mine Ventilation System

Abstract

This invention is a system for ventilating underground mines wherein each fan that ventilates a workplace or heading is installed behind a ventilation door in an access to a non-pressurised ventilation shaft (the intake vent shaft) and the air that returns from the workplaces and headings flows naturally to the surface. There are no surface ventilation fans and there is no separation of a primary and secondary ventilation circuit.

1 - 8 . (canceled) 
     
     
         9 . A system for ventilating underground mines wherein each fan that ventilates a workplace or heading is installed behind a ventilation door in an access to a non-pressurised ventilation shaft or decline (the vent intake) and the air that returns from the workplaces and headings flows naturally to the surface up the main travelway assisted by the heat that it has gained from mining activity. 
     
     
         10 . system according to  claim 9  wherein the vent intake also serves 
       as a second means of egress from the mine, ie a fresh-air escapeway. 
     
     
         11 . A system according to the  claim 9  wherein a sufficient portion of the return air is bled off the main travelway through a finger-rise into a non-pressurised exhaust vent shaft to maintain air quality in the upper part of the main travelway to within required parameters. 
     
     
         12 . A system according to  claim 9  wherein a workplace that is such a distance from the vent intake that friction loss in the ventilation ducting will reduce the output to below the required standard has a separate development of a cross-sectional area as low as  2  square metres from the workplace to the ventintake with the fan and a vent door at the workplace so that a relatively short length of ventilation ducting is required from the vent fan and so that there is a fresh-air escapeway close by. 
     
     
         13 . A system according to  claim 9  wherein each level access slopes downwards past the vent access to a sump before sloping upwards with the vent access and the sump located on the side of the level access adjacent to the uphill side of the main travelway and a stockpile area created opposite the vent access and a location for trucks to park while being loaded (a truck cuddy) created between the stockpile and the main travelway so that in the event that a truck catches fire while in the cuddy, smoke will not enter the level and personnel from the workings will not have their access to the escapeway blocked. 
     
     
         14 . A system according to  claim 9  wherein a vehicle of a similar design to a light tanker as used by Western Australian fire services but with a space created for carrying a stretcher is made available at the bottom of the mine so that a fire in the main travelway can be attacked from below. 
     
     
         15 . A system according to  claim 9  wherein the vent door on the lowest access to the vent shaft is fitted with a number of flaps that remain closed under their own weight and with the assistance of the slight negative pressure that occurs within the vent shaft relative to that outside the vent door while there are fans running but which would open if the pressure differential reversed to allow for some airflow to continue in the main travelway and for the vent shaft to continue to contain fresh air if all fans shutdown.