Determination of basic analysis items and geological grade in the exploration of metal placers:discussions and suggestions
The determination of basic analysis items and geological grade is the basic and important link in the explo-ration of metal placer,which has a direct impact on the development and utilization of metal placer in China.There are some differences,fuzziness or contradiction in the existing methods for determining the geological grade of sand deposits in China.It is necessary to discuss these important issues.Based on the investigation experience of coastal and shallow sea metal placer deposits for many years,combined with previous research results,this paper introduces the mainstream expression and calculation methods of placer grade in current exploration,analyzes its advantages and disadvantages,and then puts forward the improvement method for the new round of prospecting breakthrough re-quirements and discusses its feasibility.The results show that the determination of exploration grade of metal placer should follow the principles of keeping pace with the times,correctly treating errors and comprehensive evaluation,and seek the best combination of exploration cost and exploration risk.It is suggested that the traditional heavy min-eral elutriation and identification method should not be used as the basic analysis method to obtain mineral grade.It is recommended that the determination of heavy mineral content(THM％),chemical analysis method conversion and automatic mineral analysis(such as MLA)should be flexibly selected as the basic analysis items according to the exploration stage,the main purpose of exploration and the type of exploration.The cut-off grade and minimum industrial cut-off grade used to delineate the ore body can be directly determined using"heavy mineral content"or u-sing"comprehensive zoning indicators".Key research areas should be selected and compared with the traditional methods,the research and verification are carried out.At the same time,the relevant contents of the technical speci-fication system of sand exploration are discussed extensively and deeply,and the consensus is sought in order to speed up the supplementary revision.
metal placercoastal sand mineheavy mineralsbasic analytical projectsgeologic grade
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