Mining for the Future: Apart from war-related inventions like radar and rocketry, mining has facilitated more engineered innovations in the industrialized world's infrastructure than any other industry. In Technics and Civilization (1934), historian Lewis Mumford concluded that mining engineering had raised the quality of life for many humans by making the inconvenient convenient. From tunnels to railroads to elevators, the mining industry was the first to develop and utilize these technological innovations on a large-scale. For instance, the ideas behind square-set bracing, which constituted a method for reinforcing mine shafts, was an effective precursor to the development of reinforced concrete in the 1890s by French engineer François Hennebique. Without reinforced concrete, many of today's bridges, dams, highways, and skyscrapers would not exist. Nevertheless, the origins of mining date back to the Paleolithic Age (c. 40,000 years ago). As a process, mining involves the extraction of minerals from the Earth. These minerals are initially confined in an ore material, but later become refined into a purer substance. Coal mining, for example, is perhaps the most pervasive and pernicious form of mining today. Although coal represents one of the world's most abundant resources, mining it can release various toxic gases, including hydrogen sulfide.