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Re: [ai-geostats] Adding kriging variances.

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  • 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
    Message 1 of 4 , Nov 7, 2005
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      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
       

      Digby Millikan <digbym@...> 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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