Spectral imaging of kimberlite drill core for mineral mapping

用于矿物测绘的金伯利岩钻芯光谱成像

• 批准号: 446595-2012
• 负责人: Rivard, Benoit
• 金额: $ 3.53万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=554464
• 关键词: Spectral; imaging; kimberlite; drill; core

Kimberlites are a group of volatile-rich (primarily CO2) potassic ultramafic igneous rocks, which can contain diamonds as an accessory mineral. Worldwide, less than 1% of the kimberlites contain diamonds in sufficient quantities to be economically viable. Kimberlites are characterized by a distinctly inequigranular texture, which results from the presence of macrocrysts and/or megacrysts (primarily olivine) that are set in a finer-grained matrix. The concentration of diamonds, i.e. the diamond grades within a single kimberlite ore body can vary substantially over short distance, which makes an efficient extraction process challenging. Diamond grades are greatly influenced by the texture of a kimberlite and by the modal abundance of its mineral constituents. For a reliable prediction of the diamond grade, it is, therefore, valuable to determine the modal abundance of the mineral components within a kimberlite accurately and with high spatial resolution. In this process, particular emphasis has to be put on the distinction between mineral phases that are genetically linked to diamonds, such as mantle-derived olivine macrocrysts, and mineral/rock components that cause a dilution of the kimberlite ore, such as country rock xenoliths. To assist with this, we propose using reflectance spectroscopy imaging technology. Using visible, near-infrared, and mid-infrared wavelengths, we aim to create accurate mineral map images using reflectance imaging spectroscopy for kimberlite drill cores. These images will be used to identify and label different kimberlite facies, and assist with the grade assessment of the drill core.

金伯利特人是一组挥发性富含挥发性的（主要是二氧化碳）的钾超镁铁质岩石，可以包含钻石作为辅助矿物。在全球范围内，不到1％的金伯利岩含有足够数量的钻石在经济上可行。金伯利岩的特征是明显的不足的纹理，这是由于大晶和/或巨晶（主要是橄榄石）的存在而产生的，这些（主要是橄榄石）设置在较细粒的基质中。钻石的浓度，即单个金伯利特矿体内的钻石等级可能会在很短的距离内差异很大，从而使有效的提取过程具有挑战性。钻石等级受到金伯利岩的质地和矿物成分的模态丰度的极大影响。因此，为了对钻石等级的可靠预测，确定金伯利岩内矿物成分的模态丰度非常有价值，并具有高空间分辨率。在此过程中，必须特别强调与钻石相关的矿物相之间的区别，例如地幔衍生的橄榄石大晶体，以及导致金伯利特矿石稀释的矿物/岩石成分，例如乡村岩石Xenoliths。为了帮助这一点，我们建议使用反射光谱成像技术。使用可见的，近红外和中红外波长，我们旨在使用金伯利特钻芯的反射成像光谱创建准确的矿物图图像。这些图像将用于识别和标记不同的金伯利特相，并协助对钻头的级评估。