地下开矿对地下水疏干的影响半径研究

地F开矿首先得疏千矿井涌水。开矿疏十水属于宝贵的地下水资源，因为它不但拥有稳定的水量，并且处理其中的污染，转化成清洁水源的过程较为简单。由此可见，研究和预测地下开矿的疏干水水量关系重大，必须得到足够的重视。大井法，廊道法等等都是常用的预测方法，其中影响半径确定的准确与否对预测矿井涌水量的影响十分重大，因此，只有正确选择影响半径的推求方法，才能够保证矿井涌水量预测的准确性和可靠性，进而才能够对矿井疏干水的利用起到积极的作用。本文首先详细介绍了矿井用水量精度各个级别的情况，接着阐述了各种条件下，影响半径的各种计算方法，并探讨了其中存在的一些问题。

露天─地下联合采矿法研究的进展及其应用前景

综述了前苏联联合采矿法的研究进展，展望了我国铁矿山的应用前景及要解决的问题。

Frictional heat analysis of mine hoist and numerical simulation on temperature field of gasket

The frictional performance of gaskets is greatly affected by frictional heat in operational mine hoists. Based on frictional mechanism and heat transfer theory, the mathematical model of the temperature field of the PVC gasket in an operational mine hoist was investigated, a numerical simulation using ANSYS is presented and the distribution of the temperature and heat flux were studied under basic assumptions. The results show that the temperature gradually decreases as the radius of the model increases and the isotherms are arcs of concentric semi-circle. The heat flux is of bilateral symmetry in the model and decreases radially. The theoretical values correspond with the measured values for a short time (τ≤ 100 s) when the steel wire rope slides.

Accuracy of forecast of mine tremors location

The Upper Silesian Coal Basin is one of the most active mining areas in the world in respect of seismicity. Underground mining in this area takes place in a special environment with a high degree of risk of unpredictable event occurrence. Especially dangerous are phenomena that occur during the extraction of deposits at great depths in the environment of compact rocks. Deep underground mining violates the balance of these rocks and induces dynamic phenomena at the longwall life （in terms of distance） referred to as mine tremors. The sources of these tremors are located in layers characterised by high strength, especially in thick sandstone strata occurring in the roof of the mined seam. In the paper a discussion is presented about the influence of mining intensity （longwall face speed） on the location of mine tremor sources, both in the direction of longwall life （in terms of distance） and towards the surface. The presented material has been prepared basing on the results of tests and measurements carded out at the Central Mining Institute.

Numerical simulation study of the influence on stability of slope by underground mining under opencast coal mine slope

In view of the study on mining transferred from open-pit to underground, the research on the problem of the stabil- ity of slope is less. This article combined the actual situation of the Gaohai Coal Mine in Fuxin City and set up a three-dimensional model of the part of Huizhou open-pit slope by the finite difference software. Through the three-dimensional numerical simulation study of the influence on the stability of slope by underground mining, the basic characteristics of the open-pit slope deformation and the situation of basic stability were discussed. The simulation results of the mining slope of the displacement and deformation analysis of the state for mining provide a reference to the slope stability research.

Mining-induced variation in water levels in unconsolidated aquifers and mechanisms of water preservation in mines

Phreatic water resources are widely found in thick unconsolidated surface layers in western China, where water levels respond sensitively and quickly to large-scale underground mining in conjunction with shallow coal seams. Longwall face #32201 of the Bulianta Coal Mine, in the Shendong coalfield was selected as an industrial trail base, where field observations on ground-water levels were conducted when the working face was below a water-rich area. The space-time variation in the behavior of un-consolidated water levels in response to underground mining and its relation with of advance were observed through the field trials. The basic conditions for water preservation in mines are presented and the mechanisms of water preservation in mining analyzed, given the geological condition of two key strata and a severely weathered layer buried in the overburden. The field trails show that water preservation in mining shallow coal seams can be successful under suitable conditions, providing new technology for envi-ronmental protection in the desert coalfields of northwestern China.

Illumination of parameter contributions on uneven break： phenomenon in underground stoping mines

One of the most serious conundrum facing the stope production in underground metalliferous mining is uneven break （UB： unplanned dilution and ore-loss）. Although the UB has a huge economic fallout to the entire mining process, it is practically unavoidable due to the complex causing mechanism. In this study, the contribution of ten major UB causative parameters ha,; been scrutinised based on a published UB predicting artificial neuron network （ANN） model to put UB under the engineering management. Two typical ANN sensitivity analysis methods, i.e., connection weight algorithm （CWA） and profile method （PM） have been applied. As a result of CWA and PM applications, adjusted Qrate （AQ） revealed as the most influential parameter to UB with contribution of 22,40% in CWA and 20,48% in PM respectively. The findings of this study can be used as an important reference in stope design, production, and reconciliation stages on underground stoping mine.

Analysis of factors and countermeasures of mining subsidence in Kaiyang Phosphorus Mine

Ground crack and subsidence were investigated in Kaiyang Phosphorus Mine as an example. Contribution factors to cause ground crack and mining subsidence were studied, including mining method, mining depth and ore thickness and stope size, dip angle of orebody, geological structure, nature of overburden and water contents, and roof supports, etc. Countermeasures against cracks and subsidence were put forward. The uniaxial compressive strength of compounded phosphorus gypsum after 28 d of curing period was tested to be more than 1 MPa. Phosphorus gypsum can be used as materials for the backfill of stope. By comparison and numerical simulation, cut and fill mining method with middle-deep drilling holes and ore transportation by blasting force was selected as the optimum mining method in Kaiyang Phosphorus Mine.

A remining technology of underground coal gasification at Zhongliangshan Coal Mine

The field trail used a mixture of steam and air with various levels of oxygen en- richment.Steady conditions were achieved in the field trail which produced high quality hydrogen-enriched syngas.To understand and optimize the UCG process,a simplified heat and mass transfer model was presented,providing a predictive tool for temperature and the major constituents of the syngas production.The model is compared with the field trail measurements for air and two levels of oxygen enrichment,showing reasonable agreement for the channel temperature and product syngas concentration profile.

Experimental Study of Preferential Solute Transportation During Dump Leaching

The production of dump leaching of the Dexing Copper Mine was affected by a preferential solution flow. Formative mechanism of the preferential solution flow was investigated by analyzing the relationship between both dump permeability and surface tension and ore diameter. The preferential solution flow occured in the fine ore area when the application rate was low. The preferential solution flow entered into the coarse ore area because the negative pore water pressure disappeared with an increase of the application rate. The preferential solute transportation experiment was conducted by selecting NaCl as mineral. Results of the experiment showed that the concentration of the outflow solution reduced over time. The concentration of the coarse ore area outflow solution was greater than that of the fine ore area. The process of NaCl leaching can be divided into two stages. NaCl was carried out directly by diffusion--convection during the first stage, so the leaching rate increased sharply. But in the second stage, only a small amount of NaCl dissolved in the immobile water. The leaching rate increased slowly because NaC1, dissolved in the immobile water, can only be leached by diffusion.

Study on effects of longwall mining on the underground water

It is very important for secure mining under water bodies to study the effects of Iongwall mining on the underground water. In order to study this problem, piezometers for monitoring underground water levels were established in an American coalmine. Large amounts of pre-mining and post-mining monitoring data were collected. Based on the data the effects of Iongwall mining on the underground water was studied. The results demonstrate that when the piezometer monitoring wells have an interburden thickness less than 72.7 m, the groundwater level decreases immediately to immeasurable levels and go dry after undermining. The height of the fractured zone in is 72.7-85.3 m in this geological and mining conditions. The results also show that the calculated value of fractured zone by the empirical formulae used in China is smaller than the actual results. Therefore, it is not always safe to use them in analysis of mining under water bodies.

Designing an optimal stope layout for underground mining based on a heuristic algorithm

An optimal layout or three-dimensional spatial distribution of stopes guarantees the maximum profitability over life span of an underground mining operation.Thus,stope optimization is one of the key areas in underground mine planning practice.However,the computational complexity in developing an optimal stope layout has been a reason for limited availability of the algorithms offering solution to this problem.This article shares a new and efficient heuristic algorithm that considers a three-dimensional ore body model as an input,maximizes the economic value,and satisfies the physical mining and geotechnical constraints for generating an optimal stope layout.An implementation at a copper deposit demonstrates the applicability and robustness of the algorithm.A parallel processing based modification improving the performance of the original algorithm in terms of enormous computational time saving is also presented.

Application of fuzzy logic for determining of coal mine mechanization

The fundamental task of mining engineers is to produce more coal at a given level of labour input and material costs, for optimum quality and maximum efficiency. To achieve these goals, it is necessary to automate and mechanize mining operations. Mechanization is an objective that can result in significant cost reduction and higher levels of profitability for underground mines. To analyze the potential of mechanization, some important factors such as seam inclination and thickness, geological disturbances, seam floor conditions and roof conditions should be considered. In this study we have used fuzzy logic, membership functions and created fuzzy rule-based methods and considered the ultimate objective： mechanization of mining. As a case study, the mechanization of the Tazare coal seams in Shahroud area of Iran was investigated. The results show a low potential for mechanization in most of the Tazare coal seams.

Step change approaches in coal technology and fugitive emissions research

Multi-factor productivity(MFP) in underground coal mining has been on the decline for the last decade.The mining industry requires a viable and sustainable approach to overcome the current downtrend. This is only possible by concurrently focussing on productivity improvement and operating costs reduction,delivered through both incremental and step change technology development. Four technologies are presented in this paper: fibre optic borehole sensing has been demonstrated to reveal detailed information about gas flow influx, water level and borehole blockage events occurring along the length of a surfaceto-inseam lateral. Fibre optic gas sensing has also been investigated, and this technology promises a remote, intrinsically safe, distributed solution. Recent developments in continuous water jet drilling technology have demonstrated a step change increase in drilling rates and flexibility for coal seam degassing,applicable in both surface-to-inseam and underground in-seam applications. The application of water jet technology to the cable bolt drilling problem offers potential to address a serious health and safety and productivity issue in the roadway development process.