Re: [ai-geostats] Adding kriging variances.

[Isobel Clark]

Dear Digby!

 

If your samples are Normal, your variance is chi-squared!!!

 

You can combine (not add together) kriging variances for separate blocks but, unless they are widely separated or big enough to be considered independent this is a non-trivial task. Basically you need to store how much weight is given to each sample for each block, geometry of all blocks and compute a humungeous estimation variance.

 

Generally for head grade purposes, stopes or blocks are widely separated enough to combine the variances. Weight by size and shape of block (or tonnage) as a proportion of the total -- squared.

Isobel

http://www.kriging.com

 

Digby Millikan <[EMAIL PROTECTED]> wrote:

Dear list,

 

 If you had a set of blocks is it possible to add their kriging variances together,

to get a standard error for the mine head grade, is this something that is done

in practice or has been done in the past to estimate possible deviations from a

kriged head grade?

 

Digby

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