Brass than in brass produced by cementation. These may be "natural alloys" manufactured by smelting zinc rich copper ores in redox conditions. Many have similar tin contents to contemporary bronze artefacts and it is possible that some copper-zinc alloys were accidental and perhaps not even distinguished from copper. However the large number of copper-zinc alloys now known suggests that at least some were deliberately manufactured and many have zinc contents of more than 12% wt which would have resulted in a distinctive golden color. By the 8th–7th century BC Assyrian cuneiform tablets mention the exploitation of the "copper of the mountains"
Industrial metal industrial metal techniques in this period, including Skinny Puppy (on their "Rabies", co-produced by Jourgensen), and Front Line Assembly. British band Pitchshifter, formed in 1989 by brothers Jon and Mark Clayden, also started as an industrial metal band. The band later included elements of drum and bass. Frontman JS mentions: Industrial metal's popularity led a number of successful thrash metal groups, including Megadeth, Sepultura, and Anthrax, to request remixes by "industrial" artists. Some musicians emerging from the death metal scene, such as Fear Factory, Nailbomb, Autokrator and Meathook Seed, also began to experiment with industrial. Fear Factory, from Los Angeles,