The basis of accurate mineral resource estimates is to have a geological model which replicates the nature and style of the orebody. Key inputs into the generation of a good geological model are the sample data and ma...The basis of accurate mineral resource estimates is to have a geological model which replicates the nature and style of the orebody. Key inputs into the generation of a good geological model are the sample data and mapping information. The Obuasi Mine sample data with a lot of legacy issues were subjected to a robust validation process and integrated with mapping information to generate an accurate geological orebody model for mineral resource estimation in Block 8 Lower. Validation of the sample data focused on replacing missing collar coordinates, missing assays, and correcting magnetic declination that was used to convert the downhole surveys from true to magnetic, fix missing lithology and finally assign confidence numbers to all the sample data. The missing coordinates which were replaced ensured that the sample data plotted at their correct location in space as intended from the planning stage. Magnetic declination data, which was maintained constant throughout all the years even though it changes every year, was also corrected in the validation project. The corrected magnetic declination ensured that the drillholes were plotted on their accurate trajectory as per the planned azimuth and also reflected the true position of the intercepted mineralized fissure(s) which was previously not the case and marked a major blot in the modelling of the Obuasi orebody. The incorporation of mapped data with the validated sample data in the wireframes resulted in a better interpretation of the orebody. The updated mineral resource generated by domaining quartz from the sulphides and compared with the old resource showed that the sulphide tonnes in the old resource estimates were overestimated by 1% and the grade overestimated by 8.5%.展开更多
This paper reports an application of uncertainty visualisation of a regional scale(1:50000)3 D geological geometry model to be involved in GIS-based 3 D mineral potential assessment of the Xiangxibei lead-zinc mineral...This paper reports an application of uncertainty visualisation of a regional scale(1:50000)3 D geological geometry model to be involved in GIS-based 3 D mineral potential assessment of the Xiangxibei lead-zinc mineral concentration area in northwestern Hunan District,China.Three-dimensional(3 D)geological modelling is a process of interpretation that combines a set of input measurements in geometry.Today,technology has become a necessary part of GIS-based deep prospecting.However,issues of sparse data and imperfect understanding exist in the process so that there are several uncertainties in 3 D geological modelling.And these uncertainties are inevitably transmitted into the post-processing applications,such as model-based mineral resource assessment.Thus,in this paper,first,a big-data-based method was used to estimate the uncertainty of a 3 D geological model;second,a group of expectations of geological geometry uncertainty were calculated and integrated into ore-bearing stratoisohypse modelling,which is one of the major favourable parameters of assessment for Lead-Zinc(Pb-Zn)deep prospectivity mapping in northwestern Hunan;and finally,prospecting targets were improved.展开更多
文摘The basis of accurate mineral resource estimates is to have a geological model which replicates the nature and style of the orebody. Key inputs into the generation of a good geological model are the sample data and mapping information. The Obuasi Mine sample data with a lot of legacy issues were subjected to a robust validation process and integrated with mapping information to generate an accurate geological orebody model for mineral resource estimation in Block 8 Lower. Validation of the sample data focused on replacing missing collar coordinates, missing assays, and correcting magnetic declination that was used to convert the downhole surveys from true to magnetic, fix missing lithology and finally assign confidence numbers to all the sample data. The missing coordinates which were replaced ensured that the sample data plotted at their correct location in space as intended from the planning stage. Magnetic declination data, which was maintained constant throughout all the years even though it changes every year, was also corrected in the validation project. The corrected magnetic declination ensured that the drillholes were plotted on their accurate trajectory as per the planned azimuth and also reflected the true position of the intercepted mineralized fissure(s) which was previously not the case and marked a major blot in the modelling of the Obuasi orebody. The incorporation of mapped data with the validated sample data in the wireframes resulted in a better interpretation of the orebody. The updated mineral resource generated by domaining quartz from the sulphides and compared with the old resource showed that the sulphide tonnes in the old resource estimates were overestimated by 1% and the grade overestimated by 8.5%.
基金financially supported by the National Natural Science Foundation of China(Nos.41972311,41672330)the National Key Research and Development Program of China(No.2017YFC0601501)the National Key Technology Research and Development Program of the Ministry of Science and Technology of China(No.2006BAB01A01)。
文摘This paper reports an application of uncertainty visualisation of a regional scale(1:50000)3 D geological geometry model to be involved in GIS-based 3 D mineral potential assessment of the Xiangxibei lead-zinc mineral concentration area in northwestern Hunan District,China.Three-dimensional(3 D)geological modelling is a process of interpretation that combines a set of input measurements in geometry.Today,technology has become a necessary part of GIS-based deep prospecting.However,issues of sparse data and imperfect understanding exist in the process so that there are several uncertainties in 3 D geological modelling.And these uncertainties are inevitably transmitted into the post-processing applications,such as model-based mineral resource assessment.Thus,in this paper,first,a big-data-based method was used to estimate the uncertainty of a 3 D geological model;second,a group of expectations of geological geometry uncertainty were calculated and integrated into ore-bearing stratoisohypse modelling,which is one of the major favourable parameters of assessment for Lead-Zinc(Pb-Zn)deep prospectivity mapping in northwestern Hunan;and finally,prospecting targets were improved.
