Loading ...
Sorry, an error occurred while loading the content.

AI-GEOSTATS: Search Strategy

Expand Messages
  • Julhendra Solin
    Dear All, I am working on blasthole interpolation in open pit mine. Interpolation using ordinary kriging and grades interpolated also from above bench.
    Message 1 of 3 , Dec 18, 2001
    • 0 Attachment
      Dear All,

      I am working on blasthole interpolation in open pit mine. Interpolation
      using ordinary kriging and grades interpolated also from above bench.
      Blasthole spacing about 10 m and bench height 15 m. Anybody could help me
      how to determine search distance and min/max of number of samples to krige
      the grade. May be some technical paper related to it.

      Thanks.

      Jul


      --
      * To post a message to the list, send it to ai-geostats@...
      * As a general service to the users, please remember to post a summary of any useful responses to your questions.
      * To unsubscribe, send an email to majordomo@... with no subject and "unsubscribe ai-geostats" followed by "end" on the next line in the message body. DO NOT SEND Subscribe/Unsubscribe requests to the list
      * Support to the list is provided at http://www.ai-geostats.org
    • Nicholas Lewin-Koh
      Hi, I hope this is not a dumb question. I have set of sites which are discrete and connected by a graph. On each site (vertex in graph theory parlance) lives a
      Message 2 of 3 , Dec 18, 2001
      • 0 Attachment
        Hi,
        I hope this is not a dumb question. I have set of sites which are discrete
        and connected by a graph. On each site (vertex in graph theory
        parlance) lives a population which is modeled as a discrete time ricker
        model, n(t+1)=n(t)exp[r(1-n(t)/k) + e] - E + M, E is a proportion of the
        population migrating out only along the edges of the graph and M is the
        sum of migrants coming in for other vertices and e is a random error
        term correlated in space but independent in time. Now I am interested in
        the correlation cor(v_i, v_j) as a function of distance. I set the
        migration to zero, so that after a sufficient amount of time all
        populations hover around their equilibrium K. I have the correlation in
        the random errors e specified as p^||s_i-s_j||, an isotropic covariance
        that is a function of distance alone.

        Now the question, if I calculate all pairwise correlations between
        vertices and fit a smoother, I recover the specified corelation function
        with very little bias (provided t is large enough), and this seems to work
        for a relatively small sample of vertices. However if I caculate the
        auto-correlation function using the standard estimators and average them
        over time, or calculate the average of the standardized populations and
        fit the auto-correlation function, the result is severely biased (under
        estimates) the correlation as a function of distance, even for large v. I
        have some hunches about this, but does anyone know where I can find
        some more information on this?

        Nicholas

        CH3
        |
        N Nicholas Lewin-Koh
        / \ Dept of Statistics
        N----C C==O Program in Ecology and Evolutionary Biology
        || || | Iowa State University
        || || | Ames, IA 50011
        CH C N--CH3 http://www.public.iastate.edu/~nlewin
        \ / \ / nlewin@...
        N C
        | || Currently
        CH3 O Graphics Lab
        School of Computing
        National University of Singapore
        The Real Part of Coffee kohnicho@...


        --
        * To post a message to the list, send it to ai-geostats@...
        * As a general service to the users, please remember to post a summary of any useful responses to your questions.
        * To unsubscribe, send an email to majordomo@... with no subject and "unsubscribe ai-geostats" followed by "end" on the next line in the message body. DO NOT SEND Subscribe/Unsubscribe requests to the list
        * Support to the list is provided at http://www.ai-geostats.org
      • Isobel Clark
        Julhendra That is what your semi-variogram is for. Determine maximum distance and anisotropy (change with direction) from your experimental semi-variograms.
        Message 3 of 3 , Dec 19, 2001
        • 0 Attachment
          Julhendra

          That is what your semi-variogram is for. Determine
          maximum distance and anisotropy (change with
          direction) from your experimental semi-variograms.

          Your search strategy should also change with the shape
          of your blast layout. Single blast patterns are
          usually 'long and thin', meaning that a circular
          search would be less than optimal. I don't know of any
          papers which discuss this, but you can see our
          strategy in the kriging game. This is freely
          downloadable at:

          http://uk.geocities.com/drisobelclark/briefcase.html

          and allows you to experiment with search patterns and
          changes in semi-variogram model. It also allows you to
          see the difference between kriging as a 'point'
          estimation method (for mapping) and kriging an average
          over a blast area. Unfortunately, this free package is
          only 2d, but you may find it useful.

          One other point you may find useful. In my experience,
          working in 3d reduces to using the previous bench
          blastholes. A full 3d approach is only useful if you
          have good diamond or percussion drilling within the
          search volume. If you are going to combine sampling
          types, you need to determine whether the samples are
          compatible or to use a co-kriging approach.

          Isobel Clark



          --- Julhendra Solin <Julhendra_Solin@...> wrote:
          > Dear All,
          >
          > I am working on blasthole interpolation in open pit
          > mine. Interpolation
          > using ordinary kriging and grades interpolated also
          > from above bench.
          > Blasthole spacing about 10 m and bench height 15 m.
          > Anybody could help me
          > how to determine search distance and min/max of
          > number of samples to krige
          > the grade. May be some technical paper related to
          > it.
          >
          > Thanks.
          >
          > Jul
          >
          >
          > --
          > * To post a message to the list, send it to
          > ai-geostats@...
          > * As a general service to the users, please remember
          > to post a summary of any useful responses to your
          > questions.
          > * To unsubscribe, send an email to majordomo@...
          > with no subject and "unsubscribe ai-geostats"
          > followed by "end" on the next line in the message
          > body. DO NOT SEND Subscribe/Unsubscribe requests to
          > the list
          > * Support to the list is provided at
          http://www.ai-geostats.org

          __________________________________________________
          Do You Yahoo!?
          Everything you'll ever need on one web page
          from News and Sport to Email and Music Charts
          http://uk.my.yahoo.com

          --
          * To post a message to the list, send it to ai-geostats@...
          * As a general service to the users, please remember to post a summary of any useful responses to your questions.
          * To unsubscribe, send an email to majordomo@... with no subject and "unsubscribe ai-geostats" followed by "end" on the next line in the message body. DO NOT SEND Subscribe/Unsubscribe requests to the list
          * Support to the list is provided at http://www.ai-geostats.org
        Your message has been successfully submitted and would be delivered to recipients shortly.