vertical mining rate
71Newcomen steam engine — Animation of a schematic Newcomen steam engine. – Steam is shown pink and water is blue. – Valves move from open (green) to closed (red) The atmospheric engine invented by Thomas Newcomen in 1712, today referred to as a Newcomen steam engine (or… …
72Fault (geology) — Part of a series on earthquakes Types Foreshock • Aftershock • Blind thrust Doublet • Interplate • …
73Trip hammer — A trip hammer (alt. helve hammer) is a massive powered hammer, usually raised by a cam and then released to fall under the force of gravity. Historically, trip hammers were often powered by a water wheel, known to be used in China as long ago as… …
74lake — lake1 /layk/, n. 1. a body of fresh or salt water of considerable size, surrounded by land. 2. any similar body or pool of other liquid, as oil. 3. (go) jump in the lake, (used as an exclamation of dismissal or impatience.) [bef. 1000; ME lak(e) …
75Lake — /layk/, n. Simon, 1866 1945, U.S. engineer and naval architect. * * * I Relatively large body of slow moving or standing water that occupies an inland basin. Lakes are most abundant in high northern latitudes and in mountain regions, particularly …
76Anthropology and Archaeology — ▪ 2009 Introduction Anthropology Among the key developments in 2008 in the field of physical anthropology was the discovery by a large interdisciplinary team of Spanish and American scientists in northern Spain of a partial mandible (lower… …
77Minnesota — This article is about the U.S. state of Minnesota. For the river, see Minnesota River. For other uses, see Minnesota (disambiguation). State of Minnesota …
78Economy of Australia — Infobox Economy country = Australia width = 290 caption = Change in Australian GDP (red) and consumer price index (blue), 1970 2006. Source Reserve Bank of Australia currency = Australian Dollar ($A or A$, AU$ or $AU, AUD) year = 1 July 30 June… …
79Yunnan — Not to be confused with Yunan (disambiguation). Coordinates: 24°30′N 101°30′E / 24.5°N 101.5°E / 24.5; 101.5 …
80North America — North American. the northern continent of the Western Hemisphere, extending from Central America to the Arctic Ocean. Highest point, Mt. McKinley, 20,300 ft. (6187 m); lowest, Death Valley, 276 ft. (84 m) below sea level. 400,000,000 including… …
