a skeleton team of men will remain to service the colliery until it is finally dismantled. Coal mining was never a major industry in Ireland, apart from a spell in the mid-19th century when east Tyrone collieries were at their peak. Deerpark Mines was the largest opencast site. In 1919, it got rail connections and reached peak production in the 1950s. United States Anthracite (or "hard" coal), clean and smokeless, became the preferred fuel in cities, replacing wood by about 1850. Bituminous (or "soft coal") mining came later. In the mid-century Pittsburgh was the principal market. After 1850 soft coal, which is cheaper but dirtier, came into demand for railway locomotives and stationary steam engines, and was used to make coke for steel after 1870. Total coal output soared until 1918; before 1890, it doubled every ten years, going from in 1850 to 40 million () in 1870, 270 million () in 1900, and peaking at in 1918. New soft coal fields opened in Ohio, Indiana and Illinois, as well as West Virginia, Kentucky and Alabama. The Great Depression of the 1930s lowered the demand to in 1932. Under John L. Lewis, the United Mine Workers (UMW) became the dominant force in the coal fields in the 1930s and 1940s, producing high wages and benefits. In 1914 at the peak there were 180,000 anthracite miners; by 1970 only 6,000 remained. At the same time steam engines were phased out in railways and factories, and bituminous coal was used primarily for the generation of electricity. Employment in bituminous peaked at 705,000 men in 1923, falling to 140,000 by 1970 and 70,000 in 2003. UMW membership among active miners fell from 160,000 in 1980 to only 16,000 in 2005, as coal mining became more mechanized and non-union miners predominated in the new coal fields. In the 1960s a series of mergers saw coal production shift from small, independent coal companies to large, more diversified firms. Several oil companies and electricity producers acquired coal companies or leased Federal coal reserves in the west of the United States. Concerns that competition in the coal industry could decline as a result of these changes were heightened by a sharp rise in coal prices in the wake of the 1973 oil crisis. Coal prices fell in the 1980s, partly in response to oil price movements, but primarily in response to the large increase in supply worldwide