Improving short-term grade block models: alternative for correcting soft data

Abstract Short-term mining planning typically relies on samples obtained from channels or less-accurate sampling methods. The results may include larger sampling errors than those derived from diamond drill hole core samples. The aim of this paper is to evaluate the impact of the sampling error on g...

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Main Authors: Cristina da Paixão Araújo, João Felipe Coimbra Leite Costa, Vanessa Cerqueira Koppe
Format: Article
Language:English
Published: Fundação Gorceix
Series:REM: International Engineering Journal
Subjects:
Online Access:http://www.scielo.br/scielo.php?script=sci_arttext&pid=S2448-167X2018000100117&lng=en&tlng=en
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author Cristina da Paixão Araújo
João Felipe Coimbra Leite Costa
Vanessa Cerqueira Koppe
author_facet Cristina da Paixão Araújo
João Felipe Coimbra Leite Costa
Vanessa Cerqueira Koppe
author_sort Cristina da Paixão Araújo
collection DOAJ
description Abstract Short-term mining planning typically relies on samples obtained from channels or less-accurate sampling methods. The results may include larger sampling errors than those derived from diamond drill hole core samples. The aim of this paper is to evaluate the impact of the sampling error on grade estimation and propose a method of correcting the imprecision and bias in the soft data. In addition, this paper evaluates the benefits of using soft data in mining planning. These concepts are illustrated via a gold mine case study, where two different data types are presented. The study used Au grades collected via diamond drilling (hard data) and channels (soft data). Four methodologies were considered for estimation of the Au grades of each block to be mined: ordinary kriging with hard and soft data pooled without considering differences in data quality; ordinary kriging with only hard data; standardized ordinary kriging with pooled hard and soft data; and standardized, ordinary cokriging. The results show that even biased samples collected using poor sampling protocols improve the estimates more than a limited number of precise and unbiased samples. A welldesigned estimation method corrects the biases embedded in the samples, mitigating their propagation to the block model.
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spelling doaj.art-46d83a231667408ebd34ced46acad7d92022-12-22T02:54:42ZengFundação GorceixREM: International Engineering Journal2448-167X71111712210.1590/0370-44672016710007S2448-167X2018000100117Improving short-term grade block models: alternative for correcting soft dataCristina da Paixão AraújoJoão Felipe Coimbra Leite CostaVanessa Cerqueira KoppeAbstract Short-term mining planning typically relies on samples obtained from channels or less-accurate sampling methods. The results may include larger sampling errors than those derived from diamond drill hole core samples. The aim of this paper is to evaluate the impact of the sampling error on grade estimation and propose a method of correcting the imprecision and bias in the soft data. In addition, this paper evaluates the benefits of using soft data in mining planning. These concepts are illustrated via a gold mine case study, where two different data types are presented. The study used Au grades collected via diamond drilling (hard data) and channels (soft data). Four methodologies were considered for estimation of the Au grades of each block to be mined: ordinary kriging with hard and soft data pooled without considering differences in data quality; ordinary kriging with only hard data; standardized ordinary kriging with pooled hard and soft data; and standardized, ordinary cokriging. The results show that even biased samples collected using poor sampling protocols improve the estimates more than a limited number of precise and unbiased samples. A welldesigned estimation method corrects the biases embedded in the samples, mitigating their propagation to the block model.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S2448-167X2018000100117&lng=en&tlng=enbiased samplesgrade estimateskrigingcokrigingsampling error
spellingShingle Cristina da Paixão Araújo
João Felipe Coimbra Leite Costa
Vanessa Cerqueira Koppe
Improving short-term grade block models: alternative for correcting soft data
REM: International Engineering Journal
biased samples
grade estimates
kriging
cokriging
sampling error
title Improving short-term grade block models: alternative for correcting soft data
title_full Improving short-term grade block models: alternative for correcting soft data
title_fullStr Improving short-term grade block models: alternative for correcting soft data
title_full_unstemmed Improving short-term grade block models: alternative for correcting soft data
title_short Improving short-term grade block models: alternative for correcting soft data
title_sort improving short term grade block models alternative for correcting soft data
topic biased samples
grade estimates
kriging
cokriging
sampling error
url http://www.scielo.br/scielo.php?script=sci_arttext&pid=S2448-167X2018000100117&lng=en&tlng=en
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AT joaofelipecoimbraleitecosta improvingshorttermgradeblockmodelsalternativeforcorrectingsoftdata
AT vanessacerqueirakoppe improvingshorttermgradeblockmodelsalternativeforcorrectingsoftdata