The tropical island of Java, Indonesia, has sweeping beaches, lush landscapes, and majestic mountains. But in late 2010 the eruption of Java’s Mount Merapi volcano made parts of the island an ugly nightmare. Huge gas clouds and fiery rocks spewed high into the air. Glowing lava snaked down the mountainside. Showers of ash draped homes and fields in ghostly gray. Later, search and rescue teams hunted for survivors but found mostly bodies, some charred, caught in mid-flight. In the end, hundreds of people were killed. This powerful eruption is just one illustration of why many Earth scientists focus on the study of plate tectonics.

An analysis is performed for the magnetization, coercive force, and chemical composition of dressing products. The use of pulsed magnetic fields made it possible to increase the content of iron in concentrate and decrease simultaneously the iron losses.

The "Abakan Ore Management" Joint-Stock Company delivers primary magnetite concentrate to the West-Siberian Metallurgical Integrated Works, where the concentration plant is absent; therefore, a poor concentrate is used, and the production efficiency decreases at the initial stage. Abakan grinding-and-concentrating plant produces primary magnetite concentrate 0-8 mm in size with an average iron and sulfur content of 48 % and up to 2.5 %, respectively. By the two-stage dry separation scheme, the tails of two size classes 0-10 and 5-20 mm form. Currently, more than 18 mln t of tails with iron mass share of 13.7 % is accumulated in tailing dump.

Although micron-size particles of metallic gold are observed at the Zarshuran gold deposit, northwest Iran, the quantities do not account for the gold concentrations determined by chemical analyses. The presence of invisible gold has been established by means of trace element electron microprobe analyses of pyrite, arsenian pyrite, orpiment, realgar, stibnite, getchellite, sphalerite, and lead sulfosalts. Quantitative point analyses indicate that invisible gold is present in anhedral pyrite, arsenian pyrite overgrowth rims on gold- and arsenic-free euhedral pyrite, in massive, network, and colloform arsenian pyrite, and in massive and colloform sphalerite intimately intergrown with colloform arsenian pyrite. Gold in these forms adequately explains the measured gold concentrations at Zarshuran. The invisible gold owes its origin to solid-solution deposition and/or encapsulation of submicron-size particles of metallic gold.