Geography of Sheffield county, from bituminous (ideal for domestic heating) to "Thick Coal", of a semi-anthracitic quality, appropriate for use in iron-smelting and in engine furnaces. Associated with the Upper Coal Measures were valuable iron ore deposits, occurring in the form of nodules. Large quantities of locally occurring fireclay were also exploited, as well as ganister (a clay used to make refractory furnace linings). The city of Sheffield derives its name from the River Sheaf which Until the 17th century was written as "Scheth" or "Sheath". Sidney Oldall Addy equates the origins of this word with the Old English "shed" (as in "water-shed")
English Institute of Sport, Sheffield Championship, held in the nearby Crucible Theatre. Qualifying matches, previously held in Prestatyn, typically take place between late February and early March. Since 2010 the EIS host qualifying matches to all snooker tournaments as well as all PTC events. The EIS-Sheffield was used by British Athletes to train for the 2012 Summer Olympics. In February 2015, it was announced that the English Institute of Sport, Sheffield would be incorporated into the Olympic Legacy Park on the site of the old Don Valley Stadium. English Institute of Sport, Sheffield The English Institute of Sport is a multi-sport facility in Sheffield, England.