1. Surface Mining Chapter 1 Introduction

2. 1.1 History of Mining 1.2 Current Status 1.3 Future Trends

3. 1.1 History of Mining 1.1.1 Introduction (1) A fascinating thread that runs through the history of mining is the continuing evolution of mining methods. (2) Often,the initial exploitation of a deposit involved rudimentary scratching at outcrops 露头 and picking up pieces of ore from the surface. (3) This surface method was then followed in many instances by the development of underground workings in the form of shafts 竖井 and galleries 平巷 (4) Finally, a surface operation, often on a large-scale, would take place. (5) Mining was the second of man’s endeavors — agriculture was the first.

4. (6) Since prehistoric time, mining has been integral and essential to man’s existence. (7) The earliest relatively large-scale mining for outcropping native copper occurred between 5000 an 15000 BC. (8) Rock fragmentation was usually achieved by the cyclical application of fire and water. (9) Loading and haulage was performed by manual labor with stone, wooden, and bronze tools for excavation and animals and human beings were used for haulage.

5. 1.1.2 Early endeavors 努力，实践 (1) Mining began with Paleolithic man about 450 ， 000 years ago. (2) The first use of metals was for decoration rather than for utility purposes because of their unusual character and rarity. (3) The cultural stages of the evolution of man 人类文明史 are associated with minerals and are the Stone Age( prior to 4000BC), Bronze Age(4000 to 1500BC), Iron Age(1500BC to 1780AD), Steel Age( 1780-1945), and the Nuclear Age( since 1945).

6. 1.1.3 Bronze age (1) Evidence of early copper mining exists in many parts of the world. (2) The advent of both the Bronze and Iron Ages was contingent upon man’s discovery of smelting 冶炼 and learning to reduce 还原 ores to native metal or alloy form. (3) The art of rock breakage 破碎 by fire setting was the first technological breakthrough in mining.

7. 1.1.4 Iron age (1) The introduction of iron for making tools and weapons changed the life of early man in a vast number of ways. (2) The earliest objects that have survived were made of meteoric iron 陨石, which contains a high percentage of nickel 镍, and which were picked up from the ground. (3) The use of iron was made feasible through the development of three processes: “steeling” 炼钢, the addition of carbon to ore, “quenching” 淬火, the sudden cooling of hot metal, and “tempering” 回火, he reheating of quenched metal to correct for brittleness.

8. 1.2 Current Status 1.2.1 Productivity (1) The average open pit productivity in the decade 1990~2000 is increasing by 50%. (2) Productivity in processing plants （选厂） has remained relatively constant during the decade. (3) Iron ore requires grinding （磨矿）, separation （选 矿）, and palletizing （球团）. (4) Copper 铜, lead 铅, zinc 锌, and other ores normally require grinding and flotation （浮选）.

9. (5) Coal may simply require washing or more sophisticated flotation and separation processes 分选. (6) The average productivity in Us metal is 937million tons for waste and 381million tons for ore,496million tons for coal. The tons of waste per man-hour is 39.6tons, 1.2.2 Technological development Precious Metals 贵重金属 (1)Innovative technology has been the utilization of hydraulic shovels 液压铲, continuous mining systems, computer-assisted production control and scheduling, and improved bulk materials conveying and handling.

10. (2) Development has been at a brisk level. (3) There have been efforts to incorporate more mine planning and scheduling techniques to improve productivity. (4) Long term development plans have been devised. leaching （溶浸） (1) A technological development introduced in the late 1960s, heap leaching, has made significant contributions to the viability （活力） of precious metals operations, both for low-grade deposits 矿床 and the reworking of old properties.

11. (2) The first commercial application of the technology occurred in the late 1960s at Carlin Gold Mining in Nevada. (3) It is in the past ten years that heap leaching 堆浸 has developed into an efficient method of treating oxidized gold and silver ore. (4) It has proven to be both an efficient way to extract 提取 precious metals from small, shallow deposits, as well as an attractive way to treat large, low-grade, disseminated deposits.

12. (5) The technology is also being used to recover the metal values from waste dumps at old mining properties. Equipment trends 设备发展趋势 (1) A most important development in surface mining in recent years has been the use of increasingly sophisticated onboard electronics and microcomputer systems for mining equipment.

13. (2) These system range from those used to assist the personnel who is operating the hydraulic shovel or walking dragline 行走形索斗铲 to managing and monitoring the performance and productivity of the mine’s mobile equipment. (3) Large shiftable mining equipment ( 移动采掘设 备 )will be necessary in the future as mining of deeper near-surface deposit becomes necessary. This will be particularly necessary where climatic conditions are extreme or overburden( 覆岩） removal is difficult. (4) The development and application of high-angle 大角度 elevating, and cross-pit conveyors results in considerable reductions in transportation costs.

14. (5) Conveyor are an alternative to trucks and other diesel-consuming transport. (6) Trucks and conveyors can be combined through using an in-pit crusher. These can be fully mobile, semi-mobile, or fixed crushing plants （固定破碎站） (7) One advantage is to reduce material to the size limit 适 合皮带运输的块度 transportable by conveyors. (8) Draglines that are crawler-mounted 安装了行走机构 have resulted in reduced time and cost of erection. A major development has been the availability of long- boom 长臂 draglines.

15. (9) Another development has been drill rigs 钻机 with computer-based programmable controllers. (10) Other significant developments include renewed interest in trolley-assist 电车, truck dispatch systems 汽车 调度系统, higher horsepower, and greater capacity. (11) Continuous surface miners ( 连续回采工艺 )have been developed that incorporate a rotating cutter drum( 旋转切 削头 ) and conveyor discharge system( 皮带输送 系统 ).

16. (12) Such surface miners are especially applicable to multiple seam 多矿脉 mining where the seams are separated by thin bands of overburden 覆岩 or in cases where seams are split and where materials of different qualities must be separated 不同品位矿石分采. (13) Surface miners can mine to very narrow limits 薄矿脉, improving resource recovery 提高矿石回收率 and providing an uncontaminated product 降低贫化率. (14) Hydraulic excavators are competitive with small to medium-size cable shovels and wheeled front-end loaders, especially in smaller open pits such as those in many of the new gold operations.

17. (15) Scrapers 挖掘机, front-end loaders and electric cable shovels （电铲） comprise the traditional equipment for surface mining. (16) All classes of conventional loading equipment have undergone design changes, including improved electrics and incorporation of health monitoring 工 况监测 and diagnostic 检测 systems. These changes are resulting in increased reliability, improved performance, and a lower unit cost of production. (17) Dredging ( 挖泥船, 砂金船 ) is an attractive means of lowering mining costs, particularly in gold operations.

18. (18) On-board radios 对讲机 and computer equipment are focal points for improved communication and control and mine haulage 运输 efficiency. (19) Other recent developments in surface mining technology include the wider use of emulsion-type 乳化炸 药 explosives ， increased use of hydraulic excavators, 液压 挖掘设备 use of in-pit crushers, and shiftable belt conveyors. 坑内破碎机和移动式皮带输送机

19. 1.3 Future trends (1) Responding to increased competition, the future of surface mining has become a showpiece( 试验场，样 本 ) for technological innovation to meet sharply rising production costs. (2) Future trends will see even greater mine productivities as a result of innovations in: Off-highway truck design and performance Hydraulic shovel reliability and durability

20. Computer-aided controls in mine operations and design Blasting agent utilization and detonation efficiencies Management planning and manpower scheduling and utilization Continuous mining and materials handling systems In closing, surface mining will continue in the forefront of innovation, mandated by the industry’s commitment for excellence in cost competition and requirements for meeting world material demands.

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