Development of a Handheld Field-Deployable Mineral Analyser

X-ray powder diffractometry is a well-established materials analysis technique which produces results directly linked to the microcrystalline structure of the sample material. It is the definitive method for the identification and quantification of the mineral content of rocks. Many materials are crystalline in nature at the micron-scale (one micron equals a thousandth of a millimetre) - rocks, soils, many raw materials and building materials, metals - and so the technique has very wide applicability both in research and industrial contexts. Standard methods generally require careful preparation of the sample. For example, rocks must be ground to a fine powder and loaded into a sample well. The sample surface must be flat, and positioned accurately within the x-ray diffraction (XRD) instrument.

A novel XRD technique which exhibits almost complete insensitivity to the shape and form of the sample is being developed at the University of Leicester. This unique characteristic enables the analysis of, for example, rock samples with no requirement for any preparation of the rock. Furthermore, the principles underlying this technique favour an especially compact and lightweight instrument design. The method is also inherently fast, aided by the lack of any sample preparation requirement.

The characteristics of this technique enable, for the first time, the development of a handheld XRD device for the rapid identification and quantification of minerals in the field. The key commercial application is in mining and quarrying, and this application will serve as the focus of the project. The project objectives are two-fold. Firstly, the technique and methodology will be developed using samples which are fully representative of problems encountered in mining. For example, in iron ore mining it is important to know the relative amounts of the iron oxide minerals hematite, magnetite and goethite. A handheld device would bring numerous advantages in mining operations, such as the rapid delineation of ore boundaries and assessment of ore grades for the efficient management of blasting, excavation and haulage operations. Secondly, a prototype handheld device will be developed for field testing. This device will be adapted from an existing handheld X-ray fluorescence (XRF) instrument. XRF is a related technique to XRD, but yields the elemental composition of the sample only, not the mineralogical composition. The new prototype will combine both XRD and XRF information about the sample.

This project is a partnership between the University of Leicester and Bruker Elemental, a division of Bruker which manufactures scientific instruments for elemental analysis, including handheld XRF instruments, and has global presence in the relevant markets.