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Show 10A 2002 April' Energy Underground mining methods account for nearly 40 percent off U.S. coal Underground or deep mining methods account for approximately 39 percent of total coal production in the United States. Although the majority of underground mines are less than 1,000 feet deep, several reach depths of about 2,000 feet. U.S. underground coal production facilities essentially fall into three basic categories: a drift mine is one that has a horizontal entry to a coalbed in a hillside; a slope mines entry is inclined from the surface to the coalbed; a shaft mine, equipped with elevators, providers vertical access to a coalbed generally deeper than one reached by a slope mine. Some underground fossil fuel is mined by the system. Mining crews excavate a series of rooms into the coalbed and leave pillars or columns of coal to help support the mine roof. Long steel expansion bolts inserted into holes bored into the roof are also used for support. When production reaches the end of the panel, the direction room-and-pill- 1 r',- ;;i : 0 ar of operations is usually reversed, with miners recovering as much coal as possible from the pillars as the roof is allowed to systematically collapse. Four mqjor processes are commonly used in mining underground coal in the United States: longwall, continuous, conventional and shortwall, with continuous and conventional systems. being Longwall- - Mining via a longwall has helped revolutionize underground coal production operations in the past 20 years. During the designated period, longwalls share of total U.S. deep mine production has risen from less than 10 percent to nearly 48 percent. In fact, longwall tonnage was slightly higher than continuous mining tonnage for the first time in history in 1994, and the trend has held true since then. The longwall consists of a rotating drum, which ia dragged across a wide coal seam, often mechanically (Continued on page 3QA) room-and-pill- HV vWsStiS m i4 ' If , J Vb- 'C I J ' ar back-and-for- th fr & Longwalls share of total U.S. deep mine production risen from less than 10 percent to approximately 48 percent The longwall consists of a rotating drum, th across' which is dragged mechanically back-and-for- & a wide coal seam, often hundreds of feet long. Loos-henedcoal tills onto a conveyor for removal from the mine. Longwall systems have hydraulic roof supports increase miner safety. as What A Standing Ovation Looks Like applause. At Phillips our number one goal is to get you back in coal production as soon as possible. From our emergency service to Phillips "better than new exchange components, were committed to meet every customers need. We can support your operation with everything from used equipment to conveyor drive sprockets made in our machine shop. This commitment to sendee is just what you've come to expect from Phillips. Its . what you'll find every time you turn to us. If you have any equipment to sell, call us! Harper Industrial Park RO. Box 1245 Beckley, WV 25802 (Phone) (Fax) www.phillipsmachine.com 304-255-05- Cell: 37 270-991-00- 21 304-255-05- 65 Reggie Fariaino, Sales Representative Home: 270438-172- 4 Fax; 270338-143- 3 |