共伴生低品位铁矿床矿体圈定和资源量统计存在问题及建议OA

In the exploration and evaluation of iron ore resources in China,current specifications generally define the cutoff grade as total iron(TFe)of 20%(or magnetic iron(mFe)of 15%)and the minimum industrial grade as TFe of 25%(or mFe of 20%)for delineating ore bodies.Since the average TFe grade of most estimated iron deposits is consistently around 30%,it is therefore reasonable to use iron ore tonnage as the statistical unit for resource estimation.In recent years,due to advancements in mining and beneficiation technologies,some associated low-grade iron ores with TFe grades below 20%,particularly magmatic vanadium-titanium magnetite deposits,have become economically viable for development and utilization.However,such deposits cannot be directly delineated as iron ore bodies using the general industrial indices specified in the current specifications.Moreover,the iron content in the estimated iron ore tonnage of these deposits is significantly lower than that of conventional lean iron ores with a TFe grade of about 30%.Simply adding low-grade iron ore resources to conventional iron ore resources cannot accurately reflect the true availability of iron ore resources.Furthermore,the grade of associated iron resources in some deposits is extremely low,and thus the statistical methods for such resources merit in-depth discussion.To address these issues,this paper first analyzes the rationality of using iron ore tonnage as the statistical object for iron ore resources and then proposes systematic solutions:introducing an"equivalent iron"index(eqTFe/eqmFe)to convert associated components such as titanium into iron grades using a titanium/iron conversion coefficient(K),thereby making them applicable to the general industrial indices of current specifications.It is proposed that low-grade iron ore tonnage be converted into"national standard ore",which is equivalent to the average grade of lean iron ores in China(TFe～30%),using a conversion coefficient(n=specification minimum industrial grade/actual minimum industrial grade,recommended to be 2.5～3)before being included in resource statistics.Additionally,associated iron resources should be statistically converted using the same method only after they have been technically and economically utilized,and deposit scales should be classified based on the converted"national standard ore"with reference to lean iron ore standards.Through case validation using relevant standards from the Panxi region and Heilongjiang Province,the equivalent iron index effectively aligns the cutoff grade of low-grade vanadium-titanium magnetite(eqTFe 21%)with that of the current specification(TFe 20%).The conversion method employing a coefficient of 2.5～3 can objectively reflect the difference in availability between low-grade ores and conventional lean iron ores.The equivalent iron index and resource conversion method proposed in this paper enable scientific evaluation and statistical accounting of low-grade associated iron resources without causing drastic fluctuations in resource data and provide a reference for other metal mineral resources(e.g.,manganese and chromium ores)that also use ore tonnage as the statistical object.