British Army uniform and equipment in World War I It contained an inner can of explosive with an outer can of metal fragments or ball bearings. The fuses that were developed for the Jam Tin Grenade were activated by friction or a by lighted taper which was often replaced by a lighted cigarette. This was followed by the highly successful Mills bomb in 1915. It was oval in shape to fit into a clenched fist and time fused. The detonator was activated by a spring driven firing pin which was restrained by a lever that in turn was locked by a safety pin. The Mills bomb was a defensive
History of the iron and steel industry in the United States 2014, only 11 integrated mills were operating in the US. Most of the steel produced has been by the growing number of mini-mills, also called specialty mills, which in 2014 numbered 113. In 1981, mini-mills produced an estimated 15% of US steel. Since 2002, steel produced by electric arc furnace, the process used by the mini-mills, has produced more than half the steel made in the US. Many companies operating integrated mills also have mini-mills. A number of bankruptcies and acquisitions between 2000 and 2014 reversed the trend of industry fragmentation. In 2000, the top three steelmakers (Nucor, US Steel,