بهبود برآورد عيار بخش شرقي كانسار مس سرچشمه با استفاده از روشهاي زمين آماري شاخص و چند نقطه اي

چكيده انگليسي :

97 Improving grade estimation in eastern part of Sarcheshmeh copper deposit using advanced indicative and multiple point geostatistics Mohamad Faez m faez@mi iut ac ir September 13 2014 Department of Mining Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Dr Nader Fathianpour fathian@cc iut ac irSupervisor Dr Hooshang Asadi Haroni hooshang@cc iut ac irAbstract The inefficacy and limitations of commonly used geostatistical estimation and simulation methods based ontwo point variogram models in resolving complex and nonlinear geological settings have been thoroughlyinvestigated in recent years by both mineral and petroleum geoscientists Due to lack of observing multiplereal data simultaneously in the course of simulation the geostatistical simulations made by two pointvariograms usually produce models that are highly different and scattered which are not representative ofactual geological structures and continuity To overcome such deficiencies a number of approaches thatincorporate the actual geological patterns beyond two point geostatistics have been introduced Multiplepoint geostatistics is one of the best methods capable of simulating nonlinear and complex structures Toalleviate the shortage of available data in real situations the multiple point geostatistics uses training images which are built upon our knowledge from previous geological studies and entire available exploratory data In current study the problem of post mineralization intrusions into the main Sarcheshmeh porphyry copperdeposit is addressed Such geological complexities may cause deviations in ore reserve estimation usingconventional methods The non mineralized dikes which have been injected in the Sarcheshmeh copperdeposit in a number of post mineralization phases are considered as barren occurrences Inclusion of suchbarren dikes into ore reserve estimation process will cause over estimates of ore reserve due to assigningmetal content in place of barren dikes In addition the complex and almost irregular injection of such dikesinto main ore body may result in producing nonlinear and complex structures which cannot be modeledaccurately with conventional two point geostatistics methods Therefore the main objective of current studywas set to evaluate the possibility of employing multiple point geostatistics approach in ore reservesimulation and estimation followed by comparing the results with other conventional variogram basedmethods To achieve such objective it was necessary to prepare suitable training image capable of reproducing 3Dspatial distribution of dikes in estimation area Then such training image was inputted into the multiple pointsimulation algorithm known as SNESIM In order to get results that are more accurate in mapping 3D spatialdistribution of dikes the main parameters of SNESIM algorithm were to be optimized In the next step theoptimized SNESIM algorithm along with training image was used to produce 50 realizations for dikeoccurrences in the entire area of reserve estimation space Next these 50 realizations were used to map thedike occurrences using the so called E type estimator The results were satisfactory showing consistentspatial continuity and distribution of dikes in plotted plans and sections The ore grade and reserve wereestimated using ordinary and indicator kriging without including dikes in deposit blocky model The resultsshowed the superiority of indicator kriging in detecting dikes compared with conventional ordinary kriging In the next step the dikes model was embedded into the estimated grades for both methods resulting in themore accurate reserve estimations Finally the results were validated using the data of boreholes which were set aside for cross validation Itwas concluded that the combination of multiple point geostatistics with indicator kriging method will resultin more accurate and realistic ore reserve estimation for porphyry copper deposits that are highlyhe

فائز، محمد

بهبود برآورد عيار بخش شرقي كانسار مس سرچشمه با استفاده از روشهاي زمين آماري شاخص و چند نقطه اي

تخمين ذخيره , تصوير آموزشي , SNESIM , كريجينگ معمولي , كريجينگ شاخص