基于可见光—近红外光谱特征的BIF铁矿原位测定方法

In-situ Determination Method of BIF Iron Ore Based on Visible and Near-Infrared Spectrum

条带状铁建造(Banded iron formation,BIF)是我国主要的铁矿资源类型,主要采用露天开采方式生产。目前采场品位确定以传统化验方法为主,存在采样密度低、化验周期长、效率低、品位测试结果滞后等不足,导致矿体边界圈定不准确,增大了矿石损失率和贫化率,并使得配矿质量受到影响。选择鞍千露天铁矿作为试验场,通过现场采样、光谱测试、模型构建、模型验证等试验流程,揭示了不同岩矿类型的光谱特征,建立了矿石品位与光谱特征之间的联系,对BIF铁矿快速原位测定方法进行了研究。结果表明:赤铁矿、磁铁矿与围岩之间的光谱特征存在显著差异,利用该类差异构建的岩矿类型识别和分类模型,其铁矿石与围岩的区分正确率为97.1%,赤铁矿和磁铁矿的区分正确率达到93.5%;利用偏最小二乘法(Partial least squares method,PLS)构建的全铁品位回归模型的反演精度达到了3.43%。上述分析可为露天铁矿实现精准开采与合理配矿提供可靠依据。

Banded iron formation(BIF)is the main type of iron ore resources in China.The main way of mining is openpit mining.At present,the determination method of grade is mainly based on traditional laboratory methods,tt has the disadvantages of low sampling density,long testing period and low efficiency,moreover,there is a lag effect in the grade test results,which leads to boundary delineation of orebodies is inaccurate,and the increasing of ore loss rate and dilution rate,beside that,the quality of ore matching is affected seriously.Taking Anqian Open-pit Mine as the test site,through field sample,spectral testing,model establishment,model validation test processes to reveal spectral characteristics of different rock types.The relationship between grade and spectral characteristics is established,and the method for rapid in-situ determination of BIF iron ore is studied.The results show that there are significant spectral differences among hematite,magnetite and surrounding rocks,the rock and iron ore type identification and classification model based on these differences is established,its distinction accuracy between iron ore and surrounding rock is 97.1% and the distinction accuracy between hematite and magnetite is 93.5%;the grade regression model established by partial least squares method(PLS)has a precision of 3.54%.The above study results laid a foundation for the accurate mining and rational ore matching of open-pit iron mine.