1、英文文献Roadheader applications in mining and tunneling industriesH. Copur1, L. Ozdemir2, and J. Rostami31Graduate Student, 2 Director and Professor, and 3 Assistant ProfessorEarth Mechanics Institute, Colorado School of Mines, Golden, Colorado, 80401ABSTRACT Roadheaders offer a unique capability and fl
2、exibility for the excavation of soft to medium strength rock formations, therefore, are widely used in underground mining and tunneling operations. A critical issue in successful roadheader application is the ability to develop accurate and reliable estimates of machine production capacity and the a
3、ssociated bit costs. This paper presents and discusses the recent work completed at the Earth Mechanics Institute of Colorado School of Mines on the use of historical data for use as a performance predictor model. The model is based on extensive field data collected from different roadheader operati
4、ons in a wide variety of geologic formations. The paper also discusses the development of this database and the resultant empirical performance prediction equations derived to estimate roadheader cutting rates and bit consumption.INTRODUCTION The more widespread use of the mechanical excavation syst
5、ems is a trend set by increasing pressure on the mining and civil construction industries to move away from the conventional drill and blast methods to improve productivity and reduce costs. The additional benefits of mechanical mining include significantly improved safety, reduced ground support re
6、quirements and fewer personnel. These advantages coupled with recent enhancements in machine performance and reliability have resulted in mechanical miners taking a larger share of the rock excavation market. Roadheaders are the most widely used underground partial-face excavation machines for soft
7、to medium strength rocks, particularly for sedimentary rocks. They are used for both development and production in soft rock mining industry (i.e. main haulage drifts, roadways, cross-cuts, etc.) particularly in coal, industrial minerals and evaporitic rocks. In civil construction, they find extensi
8、ve use for excavation of tunnels (railway, roadway, sewer, diversion tunnels, etc.) in soft ground conditions, as well as for enlargement and rehabilitation of various underground structures. Their ability to excavate almost any profile opening also makes them very attractive to those mining and civ
9、il construction projects where various opening sizes and profiles need to be constructed. In addition to their high mobility and versatility, roadheaders are generally low capital cost systems compared to the most other mechanical excavators. Because of higher cutting power density due to a smaller
10、cutting drum, they offer the capability to excavate rocks harder and more abrasive than their counterparts, such as the continuous miners and the borers. ROADHEADERS IN LAST 50 YEARS Roadheaders were first developed for mechanical excavation of coal in the early 50s. Today, their application areas h
11、ave expanded beyond coal mining as a result of continual performance increases brought about by new technological developments and design improvements. The major improvements achieved in the last 50 years consist of steadily increased machine weight, size and cutterhead power, improved design of boo
12、m, muck pick up and loading system, more efficient cutterhead design, metallurgical developments in cutting bits, advances in hydraulic and electrical systems, and more widespread use of automation and remote control features. All these have led to drastic enhancements in machine cutting capabilitie
13、s, system availability and the service life. Machine weights have reached up to 120 tons providing more stable and stiffer (less vibration, less maintenance) platforms from which higher thrust forces can be generated for attacking harder rock formations. . The cutterhead power has increased signific
14、antly, approaching 500 kW to allow for higher torque capacities. Modern machines have the ability to cut cross-sections over 100m2 from a stationary point. Computer aided cutterhead lacing design has developed to a stage to enable the design of optimal bit layout to achieve the maximum efficiency in
15、 the rock and geologic conditions to be encountered. The cutting bits have evolved from simple chisel to robust conical bits. The muck collection and transport systems have also undergone major improvements, increasing attainable production rates. The loading apron can now be manufactured as an exte
16、ndible piece providing for more mobility and flexibility. The machines can be equipped with rock bolting and automatic dust suppression equipment to enhance the safety of personnel working at the heading. They can also be fitted with laser-guided alignment control systems, computer profile controlling and remote control systems allowing for reduced operator sensitivity coupled with increased efficiency and productivity. Figure-1 shows a picture of a modern transverse
