re: food for thought madprof(Q) Why would you ship an extra...

re: food for thought madprof
(Q) Why would you ship an extra 150tons?.

for safety reasons, to allow for overtreatment, to be damn sure

some answers from the prof McConchie himself when querried by US panel :

The total actual acidity is largely used to determine which Bauxsol™ reagent blend to use
and the total potential acidity is largely used to determine the quantity of Bauxsol™ reagent required.
Once the Bauxsol™ blend and quantities required have been determined, a safety margin can be
applied (overtreatment by 50% is required for acid sulphate soils work in Australia) and other
corrections can be applied based on the particle size distribution in the waste rock pile, sulphide
mineral grain size, the ANC of the rock material, etc.


How do you determine the drill spacing for injection?
By experience at many other sites and observing the behavior in adjacent holes during injection.
However, as explained above we do calculate the Bauxsol™ requirements (using the computer model
and input data described above) based on the total sulphide mineral concentration in the entire rock
such that we will have sufficient Bauxsol™ reagent present to neutralize all acidity and bind all metals
that could ever be produced. The computer model also allows for the application of whatever
additional safety factor is required,