In magnetic separators the phenomenon of magnetic flocculation is an inseparable feature of enrichment of strongly magnetic ores. Non-magnetic particles are bound in the floe internal structure by means of magnetic, surface and mechanical forces which leads to the deterioration of enrichment results. The intensity of flocculation depends on magnetic field intensity, content of the magnetic component in the feed and ore feed rate. The above mentioned factors affect the enrichment results. The paper presents the separation analysis in the band magnetic separator with respect to the magnetic field distribution in the separator working space as well as internal and external mechanical forces, acting on the particle. The author determined the effect of the magnetic compound content in the feed and the amount of washing water on the recovery of this component in the concentrate as well as the effect of the magnetic component content in the feed and the magnetic force density on the residue of the non-magnetic component in the concentrate. The analysis was performed according to the physical model of magnetic separation, presented in the paper. The theoretical dependences, derived from this model, are in good agreement with the results of empirical research, found in the literature.

Glacierized fjords are dynamic regions, with variable oceanographic conditions and complex ice−ocean interactions, which are still poorly understood. Recent studies have shown that passive underwater acoustics offers new promising tools in this branch of polar research. Here, we present results from two field campaigns, conducted in summer 2013 and spring 2014. Several recordings with a bespoke two−hydrophone acoustic buoy were made in different parts of Hornsund Fjord, Spitsbergen in the vicinity of tidewater glaciers to study the directionality of underwater ambient noise. Representative segments of the data are used to illustrate the analyses, and determine the directions of sound sources by using the time differences of arrivals between two horizontally aligned, broadband hydrophones. The results reveal that low frequency noise (< 3 kHz) is radiated mostly from the ice cliffs, while high−frequency (> 3 kHz) noise directionality strongly depends on the distribution of floating glacial ice throughout the fjord. Changing rates of iceberg production as seen for example in field photographs and logs are, in turn, most likely linked to signal amplitudes for relevant directions. These findings demonstrate the potential offered by passive acoustics to study the dynamics of individual tidewater glaciers.