In North and South America, smaller shafts are designed to be rectangular with timber supports. Larger shafts are round and are concrete lined. The material of choice for shaft lining is mass concrete which is poured behind Shaft Forms in Lifts of 6m as the shaft advances gets deeper. Shotcrete , fibrecrete, brick , cast iron tubing, precast concrete segments have all been used at one time or another.
History[ edit ] The dragline was invented in by John W. By , Page realized that building draglines was more lucrative than contracting, so he created the Page Engineering Company to build draglines. Page built its first crude walking dragline in These used legs operated by rack and pinion on a separate frame that lifted the crane. The body was then pulled forward by chain on a roller track and then lowered again.
The effects of mining coal persists for years after coal is removed. Dear Readers, please refer to this latest article regarding the serious effects of Acid Mine Drainage on the environment and human lives in South Africa. This Harvard report was just recently released in October, and is extremely in depth on the issues of the serious effects of mining on the environment and human health. Destruction and poison linger Bad mining practices can ignite coal fires, which can burn for decades, release fly ash and smoke laden with greenhouse gasses and toxic chemicals.
History[ edit ] Tipple of Mine 31 in Kenvir during September Just two years after the first coal was discovered in the United States in explorer Thomas Walker discovered coal in what would become Kentucky and used it to heat his camp fire. Although his discovery came in the Eastern Coalfield it would be another years before commercial coal production occurred there. In the first commercial coal mine in Kentucky opened in the Western Coalfield in Muhlenberg County. In its first year the mine produced tons of coal. By the state produced , tons of coal, and by the state produced one million tons of coal, all coming from the Western Coalfield.