Where’s the Dust??

Prior to drilling and blasting the ore pictured on the home page being discharged to the ROM pocket, it had a solid in situ SG of 2.7.  When loaded into the haul truck following blasting, the loose ore bulk density is much less at 1.6t/m3, however, more importantly from the dust perspective it includes 40% voidage, a 2:3 ratio. This is where the entire dust content resides when the broken ore mass is at rest.

The 300 tonnes (187m3) of static ore pictured contains a nominal 75m3 of air space within its voids.  During tipping the ore becomes further aerated by the accelerating granular solids becoming rapidly dispersed by gravity, increasing the volume of entrained engorged air due to growth in void distribution, all proportionate with rill angle saltation depth then free fall height and an aeration or voidage increase of more than double the loads original static air volume. All this drives an associated violent inrush of air that sweeps surface, and internal airborne dust, ahead of it deeper into the rapidly expanding core voids concentrating all dust content within the core air spaces of the live ore mass transiting in-trajectory through free fall.

This simply ensures that all void expansion driven by gravitational effect pulls enveloping saturated wet air inward.

The simple focus of the pre-emptive T&T Brume delivery system is to establish and maintain a saturated enveloping jacket of engorged air that surrounds the trajectory stream of ore prior to and during the entirety of every dump. It’s a sleeve of Brume.

With the ROM pocket air having been pro-actively saturated by the Barrage system prior to each dump, the wet enveloping air continues to be drawn (by ongoing internal loss of pressure) into the expanding mass of ore in flight, and in its downward cascade over and around mixed lump material until the active ore reaches its natural rill angle within the dump hopper. A complex dynamic event.

The increased engorged air content of the ore stream, the Brume, within the agitated internal voids (>40% by volume) continue to be maintained and replenished by the enveloping saturated wet Brume jacket. This event overall is very short in duration, less than 20 seconds in total.

Time lapse analysis of video footage allows visible dust to be seen disappearing, being sucked into the live transiting ore mass, all simply powered by the flying ore streams forming low internal air pressure zone resulting from particulate gravitational acceleration [Click to see updated video]

The saturated envelope of Brume is the only way by which the voids in the falling ore stream can be filled to the maximum possible degree.

The final event is sudden. The flying ore stream implodes on impact, expelling its drawn-in air volume plus its entrained free moisture content. The violence of this almost instantaneous venting of >75 cubic metres saturated air thoroughly mixes and agglomerates its wet content and airborne dust within the collapsing wetted interstitial imploding channels and pathways.   This is simply why the system is effective.

The result – where’s the dust???