The Outokumpu Scientific Deep Drill Hole intersects a 2500 m deep Precambrian crustal section comprising a 1300 m thick biotite-gneiss series (mica schists) at top, followed by a 200 m thick meta-ophiolite sequence, underlain again by biotite gneisses (mica schists) (500 m thick) with intercalations of amphibolite and meta-pegmatoids (pegmatitic granite). From 2000 m downward the dominating rock types are metapegmatoids (pegmatitic granite). Average isotropic intrinsic P-and S-wave velocities and densities of rocks were calculated on the basis of the volume fraction of the constituent minerals and their single crystal properties for 29 core samples covering the depth range 198 m 2491 m. The modal composition of the rocks is obtained from bulk rock (XRF) and mineral chemistry (microprobe), using least squares fitting. Laboratory seismic measurements on 13 selected samples representing the main lithologies revealed strong anisotropy of P-and S-wave velocities and shear wave splitting. Seismic anisotropy is strongly related to foliation and is, in particular, an important property of the biotite gneisses, which dominate the Upper and Lower gneiss series. At in situ conditions, velocity anisotropy is largely caused by oriented microcracks, which are not completely closed at the pressures corresponding to the relatively shallow depth drilled by the borehole, in addition to crystallographic preferred orientation (CPO) of the phyllosilicates. The contribution of CPO to bulk anisotropy is confirmed by 3D velocity calculations based on neutron diffraction texture measurements. For vertical incidence of the wave train, the in situ velocities derived form the lab measurements are significantly lower than the measured and calculated intrinsic velocities. The experimental results give evidence that the strong reflective nature of the ophiolite-derived rock assemblages is largely affected by oriented microcracks and preferred crystallographic orientation of major minerals, in addition to the lithologic control.

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The affinity of Nd and Dy to phosphate containing mineral phases was investigated in this study in an Al 2 O 3 -CaO-MgO-P 2 O 5 -SiO 2 slag system. The slags originate from pyrometallurgical recycling of NdFeB magnets. Without addition of phosphate, the distribution of Nd and Dy is more or less arbitrary in the silicate matrix. Addition of phosphate leads to the formation of a silico-phosphate in an early stage of the crystallization process, which scavenges the majority of Nd and Dy. This is due to the strong affinity of these elements to phosphate structures. This phenomenon could be used to produce a rare earth element concentrate by classical mineral beneficiation.

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