The N663 stope experiment at Mount Isa Mine

Summary Factors affecting the stability of a trial open stope at a depth of 1000 m in fissile foot wall and hanging wall shales are discussed. A combination of systematic support using cable dowels, and reduced disturbance from blasting using low density explosives and single ring firing, allowed successful completion of the stope.     

Stresses and displacements due to underground mining using a finite element procedure

Summary A two dimensional finite element procedure is applied to simulate a coal mining excavation sequence. A procedure with linear solution steps is developed and applied to an idealized mountain cross-section with exceptionally thick coal seams and large dip angle. The results provide information on pillar pressure, floor and roof stability, displacement characteristics and surface subsidence.The results presented here were obtained in the course of research sponsored by the Department of Energy, Mines and Resources, Grant No. 69-2570.     

Mine ventilation planning in the 1980s

Conclusions In this paper, the author has attempted to trace the development of mine ventilation planning from the traditional, manual and largely empirical methods of the past to the numerate computer-based techniques of the 1980s.The computer revolution has changed the face of many engineering disciplines, not least mine environmental engineering. Nevertheless, the mining industries of the world have not all been equally progressive in adapting to the flexibility, power and practical utilization of the new methodologies. It is, for example, incongruous that current textbooks on mine ventilation separate completely the topics of network analysis and ventilation planning with very little cross-referencing. Many of the current generation of mine ventilation engineers recognize the need to know about computers but find difficulty in translating this into their daily work. The growing availability of self-teaching, friendly software for personal microcomputers, coupled with interactive graphics, will assist greatly in promoting uncomplicated but powerful usage of computers.Young engineers now graduating from universities and colleges have been brought up in a computer-oriented environment and are competent in interacting with these machines. Indeed, they wonder how the job was ever done without magnetic data bases and high-speed computation aid.     

Use of rock classification to estimate roof caving span in oblong workings

Summary Indian coal measures have widely varying caving characteristics. The maximum roof span of a longwall or depillaring panel at the time of nether roof collapse is shown to have a direct relation withRQD from a study of 12 case histories. A similar relation between maximum unsupported span of openings and rock mass quality as defined by theQ-system was also demonstrated. A simple nomogram is presented to predict the face advance required to cause roof collapse when theRQD or rock mass quality is known.     

Roof bolting in underground mining: a state-of-the-art review

Conclusions With continuing investigations and developments, roof bolting today can in most cases successfully reinforce the mine roof in underground mining. In order to cope with the increasing use of roof bolts, efforts should be made to maximize the safety and minimize the cost. With regard to mechanical bolting, two important parameters need more advanced improvements and study, namely, optimum design of the shape and type of expansion shell and optimum bolt tension for a specific bolt pattern. For the fully grouted resin bolt, the most critical requirement is to develop a fast-setting, low-cost, intoxic, inflammable grouting material that can be used in the high speed mining cycle. It should be noted that geological conditions such as the strata type, rock properties,in situ stress, and planes of weakness play an important role in the successful application of any roof bolting system. These factors should be specified as accurately and quantitatively as possible in the design of any roof bolting system. Finally, proper and careful installation and continuous monitoring are imperative for the success of any roof bolting system.     

A generalized probabilistic approach for slope analysis: practical application to an open pit iron ore mine

Summary An example of the generalized probabilistic approach to slope analysis is given through a case study on an iron ore mine. A step by step engineering procedure is described, so that a practical application can be made to other structures under different field conditions.     

临涣矿区水化学特征及在矿井水源判别中的意义

通过分析、比较临涣矿区三个地下水子系统的水文地球化学特征得出，这三个子系统在水溶标型发及少、微量元素的含量上无明显差别，表明各子系统间存在水力联系，而环境同位素氘和＾１８Ｏ分析则是解决矿井水来源判别的有效方法。     

平顶山矿区钻探泥浆的研究

介绍了平顶山矿区地质特征、钻孔护壁概况和５种不同体系泥浆的组成特点、配方及性能参数；对泥浆的密度与固相含量、粘度与流变特性、滤水特性及防涌防漏的主要技术性能和作用机理进行了探讨；综合分析了各类泥浆的钻进技术效果和经济效益。     

Economic and design considerations for explosive overburden casting

Summary An overview of economics and design consideration for explosive overburden casting is given and the criteria for the successful application of this technique are discussed. These criteria are: blast design, economic considerations and environmental considerations. Explosive overburden casting may effect considerable cost savings if the market for increased production is available. However, if a fixed sales constraint exists the economic benefits of explosive overburden casting may be marginal and an extensive economic analysis is warranted.     

The stability of underground workings in the soft rocks of the Coal Measures

Summary The characteristics of soft rocks typical of the British Coal Measures are defined and a series of working hypotheses are developed to provide improved design methods for underground roadway and face supports and pillars in coal mines. Proposed design equations are tested against case history data.