At Hüttengrund Quarry, tectonically deformed greywacke layers are extracted and processed to high-grade aggregate and building material mixes for road construction. During crushing and sizing, around 30 000 t material filler per year is collected from the dust collection system. The quarry is operated as a part of the amo/Debus Group by Hartsteinwerk Hüttengrund GmbH. It is located north of Sonneberg in Thuringian Forest and is currently working six levels with a total height of more than 100 m (»1). Geologically speaking, the deposit lies at the southern edge...