采矿工程毕业设计英文翻译.doc

Underground MiningMost present-day mining in Europe occurs under 2000 to 4000 ft of overburden, as more easily mined coal deposits have been depleted. At this depth most mines are developed as shaft mines. All personnel, material, and coal have to be hoisted trough these shaft. Considering the two factors of hoisting capacity and required length of shaft, a considerable investment is necessary to reach the coal-bearing strata. The requires huge investments. Openings at this depth have to be equipped with costly supports, and periodic reworking and repair is necessary.Mines not only extend horizontally but also vertically through the development of new levels. The life of the mines is thus extend considerably, and surface installations can be amortize over a longer period.The more limited reserves have forced companies into mining less favorable deposits, and European government require that all possible deposits be mined to conserve the nations energy resources. These factor and the large percentage of inclined seams and faults make mining very difficult and costly. The population density and the heavy surface buildup cause additional expense in the form of payments for subsidence damage to surface structures. Therefore, backfilling is frequently practiced to reduce subsidence. The close spacing of faults often severely limits the size of a mining section, forcing frequent moves and excessive development work.The thickness of the overburden results in very high ground pressure. This would require extremely large pillars if the room and pillar method was applied. Additionally, support is required for any opening, adding prohibitive costs to a multiple-entry room and pillar operation.As a result, single-entry longwall operations requiring the minimum number of entries and allowing maximum recovery of resources is the mining method almost exclusively practiced.Shaft mines dominate the European coal mining industry. Shafts 20 to 30 ft in diameter, with circular cross section, lined with masonry, concrete, or steel are the dominant means of gaining access to the coal-bearing strata. They are often extended beyond the last mining level to provide for future expansion. As in the Unite States, shafts are developed by drilling, blasting, and excavating or by large-diameter shaft-boring equipment. Shaft boring is more frequently used, particularly on the smaller and shorter subshaft, which connect the different levels but do not extend to the surface.Haulage in the shaft is usually accomplished by hoisting of the filled mine cars on multistage cages or by skips. Pumping of coal slurry is also done in special cases.The complex system of forces and the resulting rock mechanical problems developed by mining activities at different levels result in significant differences between European and US underground development. The rock mechanical interaction of the extraction operations at the various levels require that all deposits be mined as completely as possible. Pillars left after mining create zones of extreme and often unmanageable ground control problem, as well as a high probability of roof bounce. Since the number of entries is kept to a minimum because of cost, no bleeder systems are provided. If retreat mining is practiced, only two entries are advanced in to a new mining area.Panels are laid out as large as possible. The large-panel layout is used as another means of reducing the number of entries. Mindedout panels are sealed off to prevent spontaneous combustion through the removal of oxygen.The main levels, with extensive entry systems, are used for coal, supply, and personnel haulage and for ventilation. They are often spaced with little regard to the position of the coal seams, because the deposits are reached selectively through other means. In the past, 165-or330-ft intervals were selected while increasing ground pressures and development and maintenance increase substantially, requiring large volumes of air for cooling. As a result, entry cross sections at these levels have to be increase.Fig.9.1 German multilevel, multiseam shaft-type coal mine.Underground facilities：(1) main shaft with skip hoisting;(2) exhaust ventilation shaft with multistage cage;(3) third-level station;(4) blind shaft with cylindrical storage bin;(5) blind shaft with car-hoisting facilities;(6) main entry;(7) main entry;(8) section or panel entry;(9) road heading machine(10) longwall section with plow;(11) longwall section with shearer;(12) longwall section in a steeply pitching seam mined manually with air picks;(13) longwall section in steeply pitching seam with plow;(14) minded-out gob area;(15) ventilation lock;(16) belt conveyor as main haulage;(17) main car haulage;(18) storage bin and skip-loading facilities;(19) supply haulage with a mono-rail;(20) supply haulage with mine cars;(21) monorail system as personnel carrier;(22) worker-trip cars;(23) pump station. Surface facilities:(a) hoisting tower with overhead hoist;(b) shaft building;(c) head frame;(d) main exhaust fan and diffuser;(e) coal preparation plant with loading facilities;(f) coking coal silo;(g) container vehicle for filling of coke ovens;(h) coke oven battery;(i) coke watering car;(k) coke quenching tower;(l) gas tank;(m) water-treatment plant;(n) refuse pile;(o) power plant;(p) cooling tower;(q) water tower;(r) supply storage area;(s) sawmill;(t) training and teaching center.地下采煤目前，大部分欧洲的煤矿开采都已经达到了2000到4000英尺，主要是因为浅部容易开采的煤层都已经采完。在这个深度的大部分煤层都已经发展成为要用相关井筒进行开采的地步。所用的人员、材料、煤炭都不得不从井筒采用绞车等提升进行运输。考虑到绞车提升容量以及所需要的井筒长度的两个因素，一个相当大的资金投入对于开采到煤层所处的地层是必需的。这些大范围的地下巷道或隧道的网络的开拓和维护费用需要一笔巨大的投资。在这个深度进行开拓不得不装备一些很昂贵的支架和一些循环型的改造和返修，这些也都是必要的。采矿不单单是拓宽水平方向而且通过开拓新的水平来拓宽来延深。所以矿井的服务年限被极大地拓宽，并且地表的安装设备费用也能够在很长的一个时期内得以缓冲。有限的资源储备迫使公司开采要去开采那些并不是很乐观的煤层，并且欧洲各国政府要求采出所有可采的煤层以保护国家的能源。这些因素由于大比率的煤线和断层以至于煤炭的开采非常困难并且价格昂贵。由于人口密度的增长和地表建筑的增加，从而造成地表的沉陷对于建筑物的破坏，以至于增加了额外的成本。因此，采空区填充是最常用的防治地表沉陷的实践措施。过小的断层间距常常严重地限制采区的尺寸，因而不得不频繁搬家，并造成过大的开拓工程量。上部覆盖层的厚度导致了相当大的地层压力。如果采用房柱式开采方法，就需要留异常巨大的煤柱。另外，任何一个工作面都需要支架，并且增加了额外的费用对于多种平巷峒室的支撑措施。地下开采统治着欧洲的煤炭开采工业。井筒直径大约20到30英寸，一般采用钢筋混凝土砌碹的圆形断面，作为主要的连接巷道连接到含煤地层。他们一般被延深到超过最后一个开采水平来满足未来的拓展。如在美国，立井是用打眼、放炮和挖掘方法或用大直径钻井设备来开凿的。钻井时经常被采用的，尤其对于小型的长度较短的连接各个水平但不通往地面的暗井。井筒中一般采用罐笼中承载矿车或箕斗进行提升。在特殊情况下采用煤泥泵出的形式开采。这种力的复杂的系统和岩石力学的合成的问题在煤矿开采活动不同的水平在欧洲和美国存在巨大的不同。在多个水平煤层进行开采时，岩石之间相互力的作用要求尽可能的将煤全部采出。煤矿开采后留下的煤柱形成了一个压力极高并且相当难以维护的空间，具有很高的发生顶板岩石突出的可能性。由于资金成本的问题，巷道入口的数目保持在最小值。没有回风巷的系统开始形成。如果采用后退式的开采方法，在采煤区段只有两个入口。区段一般被尽可能的大。大区段的布置方式其实从另一个角度说就是为了减少入口的数目。开采过后的区域一般打上封闭，以切断氧气的来源从而防止采空区煤层自燃。在布置有众多巷道主要