central bore baby photos

Got bored so thought I would try and work out how the Geo's estimate data. Turns out it is a thing called Kriging. Basically it is a statistical best fit.

It also turns out that because of the mix of high and low grades central bore is nasty to estimate.

Anyway the following are 2D kriging images of the central bore deposit taken from GORs drill data.

First thing to note is that I have used the Log10 of the gram per ton figure. To map it back to grams per ton raise 10 to the power of it. In excel that is the up hat thing
2^2=4, 3^2=9, 10^1=10, 10^2=100 etc.

The second thing to note is that from a technical view the CB resource is what is called Nuggety. That means I have had to use a nugget of about 0.5 in the calculations. What this means is that the grades vary a lot around the mean. Could be up or down.

The variance at its lowest is about 0.5 or 3.12 grams per ton.

The third thing to note is that these are 2D images so it is a bit like trying to work out the shape of something by looking at its shadow. It could be a box or a playing card.

The shape actually seems more of a spoon seen side on than an egg shape.

Top Down


Looking to the North from the South


Looking to the East from the West


Technically I have used variograms for the three images using the "R" statistical suite.

VarioXY.fit (lat long)
model psill range kappa
1 Nug 0.4905752 0.00000 0
2 Ste 0.1083665 71.10138 10

VarioXZ.fit (long depth)
model psill range kappa
1 Nug 0.4750000 0.00 0
2 Ste 0.1153298 98.86 10

VarioYZ.fit (lat depth)
model psill range kappa
1 Nug 0.46810558 0.00000 0
2 Ste 0.09711093 48.40646 10