A Management System to Develop Occupational Health & Safety in Ground Control Operations of Underground Mines

Falls of ground have historically been the main cause for fatalities in underground mines. Although recent advances in technology have reduced the number of such accidents, when failures occur they usually result in severe consequences. Risks of rock falls, use of heavy machinery and electrical apparatus, entry to confined spaces, working in noisy and dusty environments, and working on unstable platforms are some of the hazards in ground control operations. Managing these risks requires a management regime involving strict adherence to operational codes of practice and an enshrined culture of safety. These should be subsequently reinforced through active participation of management, systematic training, and stringent internal and third party auditing. Accident reports show that the major contributing factor in most rock fall accidents is the failure to adequately manage known risks due to the lack of a systematic process. OHSAS 18001 (Occupational Health and Safety Assessment Series) is an international occupational health and safety management standard specification to develop occupational health and safety at the workplace. This standard is intended to help mine operators control occupational health and safety risks. Addressing the requirements of OHSAS 18001 can be a complex and demanding task. A comprehensive guide for efficient and accurate implementation of this standard is provided in this paper. The discipline can be used to establish an accountable management system foreground control activities in underground coal mines. The paper also provides guidelines for preparing necessary documents, devising safety policies, procedures, performing risk assessment, and handling instructions. Finally, the paper concludes by providing a sound analytical basis in terms of the creation of a robust safety management system foreground control operations in underground mines. Full benefits of implementing an effective and systematic operational health and safety management system are illustrated. The procedure adopted and prescribed in this paper can be used in all underground coal mines where lack of appropriate ground control practices can create deficiencies in both safety and productivity

Assessment of the Dynamic Loads Effect on Underground Mines Supports

Blasting operations generate seismic effects in underground mines. These effects apply additional dynamic loads on the support system, which should bear both static and dynamic loads. Static loads are caused by the weight of the superincumbent strata, while dynamic loads occur as a result of blasting in the mining area. Identification of the origin and determination of the support system behavior in natural frequencies is crucial in assessing the stability of underground mines. This is because resonance occurs when a support is vibrated with its natural frequencies, which can cause a vibration with the maximum amplitude and subsequently cause extreme deformations. The mechanism of support system deformation during dynamic load displacement has been studied and numerical simulation for the impact of the dynamic loads on stability of supports is carried out using finite element method. The paper introduces a simple technique for improving stability and safety of mining operations. Results obtained and the methodology adopted in this research can help mining design engineers make decisions on adequate support for active mining operations

A Comparison of Numerical Methods and Analytical Methods in Determination of Tunnel Walls Displacement – A Case Study

Tunnel stability has an important role in the production process of an underground coal mine. There are various methods for analysing tunnel stability, such as numerical methods and analytical methods. In this paper, numerical methods (Phase2 software) have been used to determine tunnel wall displacement in a mining tunnel of the Parvade underground coal mine. The Ground Reaction Curve has also been drawn using analytical methods to determine tunnel wall displacement. The comparison of results from the numerical method and the analytical method show a noteworthy difference in the tunnel wall displacement. The displacement calculated by the numerical method shows a lower value than that of the analytical method because the numerical method is more suited to modeling the various coal and rock layers, as well as the shape of the excavations found in coal mines. The methodology used in this paper together with the results obtained from both methods can serve as useful tools for the coal mine design engineer when determining the ground support requirements

Designing Shotcrete As Primary Support in Tunnels

Since the advent of New Austrian Tunneling Method (NATM), shotcrete as a primary means of support in tunnels has been widely applied. It’s most important features are durability, speed of application and cost effectiveness. This paper introduces some tables that provide guidelines for the thickness of shotcrete required in some common situations of mine roadways. In order to devise such tables, two different arch sections, together with three different overburden types, were considered. Geotechnical parameters such as apparent cohesion and angle of internal friction of surrounding rocks were chosen, based on the five-category classification of Bieniawski. Two K0 factors (the ratio of horizontal stress to vertical stress) and an average rock density were utilized. Using numerical methods, 60 models were then devised in this way. By applying interaction diagrams of axial force and the bending moment for different thicknesses of shotcrete, appropriate shotcrete thickness for these models were calculated. The results of this research, as well as the methodology applied, can be used in mining roadway support design and all types of civil engineering tunnels

Analytical Model Determining the Optimal Block Size in the Block Caving Mining Method

Nowadays along with population growth, industry development, consumption of mineral resources and the fact that the reserves on hand are running out, the depth of surface and underground mines for further exploitation are increasing. During recent years, in underground mining, the block caving method for low-grade and large-scale deposits has shown a growing rate of application. The dimensions of blocks are one of the most important parameters which should be taken into account since it has been proved to have a great deal of effect on technical issues such as commencement of caving and mine design. In this study, some assumptions were considered and having used these assumptions for estimation of optimized length and width of block, a relationship was explored. And finally, it was transformed into an inequality. Solving this inequality provides us with the optimized length and width of the block. The explored relationship was analysed using MATLAB and the resulting graphs thereof were drawn. Simulation was carried out using the Phase2 software and the results were compared with the different modes of the block. In the blocks that were 55, 60 and 65m in length, the total displacement (the total displacement as a result of applying force in order to cave), yielded elements (percent) and Yielded Joints reached a satisfactory condition which enables perfect caving to occur. In addition, in the 70m block, these values reached their maximum. It was concluded in this paper that the optimal block size is between 55 and 65m

The Evaluation of Empirical Coal Pillar Strength Formula Based on Uncertainty Criterion

Several empirical equations to estimate coal pillar strength have been presented in academic studies. The development processes of these equations are similar and are usually obtained by fitting the mathematical function (curve) to field data. One of the best criteria to evaluate the quality of fitting for such equations is the correlation coefficient R2, which has limited applicability. It is necessary to calculate the correlation coefficient access to the initial data for which the equation is presented; this is impossible for many coal pillar strength formulas. This paper presents a new approach based on the analysis of uncertainty amplitude to compare the coal pillar strength. This approach utilizes a combination of parameters such as Mean Squared Error (MSE), Root Mean Squared Error (RMSE), function type and degrees of freedom. The confidence level of constants is subsequently formed and the correlation coefficient becomes more comprehensive. Therefore, for an effective comparison, the efficiency and accuracy of coal pillar strength formula can be used

General Approach to Distribute Waste Rocks Between Dump Sites in Open Cast Mines

In most surface mining operations, waste rocks are removed from the pit and deposited on adjacent areas. Mine optimization is a key step in the viability of a surface mining project. Definition of approaches for selection of haulage tracks and waste distribution to dumps on the basis of minimizing the haulage cost is one of the main parameters in optimization. Cost estimation, linear programming and decision-making tools are applied in optimization. Cost estimation is performed to obtain the primary information for the linear programming process. In order to ensure high operating efficiency, linear programming has focused on haulage optimization. The waste distribution program is a complex engineering decision of enormous economic significance. This paper presents an approach to minimize transportation costs of waste rocks. Finally, a real mining operation is demonstrated that highlights the advantages of such approach

Feasibility study of Gol-Gohar iron ore open cast mine operation of Iran

Feasibility study of the mining operation is one of the most important parts of the total mineral exploitation process. The economic importance of this, increases with the size of the mineral reserves. Gol-Gohar is one of the largest iron ore mines in Iran with an annual output of some 11 million tons. In this paper, the total costs associated with Gol-Gohar open cast mine have been calculated. These have been divided into capital cost, labor cost, energy and materials and supplies costs. Total revenues have also been estimated based on reliable forecasts for future. The results have then been analyzed and in particular, the effects of the inflation of prices on costs and other variables have been fully demonstrated. The paper calculates that the results obtained from feasibility studies of mining operations, can be affected seriously when uncertainties are present in the economy and when there are instabilities in the general price levels. It has also been concluded that fluctuations in the exchange rates can have a dramatic impact on the success of such long term activities

Coal mining in the UK : recent effects of technological change on productivity and safety

The thesis starts by defining technological change, productivity and safety. Different definitions are discussed and their merits compared. A brief history of coal mining, together with a description of the state of the mining industry at present is given. Technological innovations recently adopted by the industry are discussed. The concept of productivity in relation to the coal industry of the U.K., and the deficiencies of the present measurement technique, are fully explained. Safety in the coal mining industry of the U.K. is investigated. A brief history is given, together with a full discussion of the consequences and costs of accidents. The concept of technical productivity is introduced and its relation to total productivity explained. The total productivity concept is then applied to longwall coal faces. A multi-variable non-linear model is devised which represents mean total productivity of all longwall faces to an accuracy of about J7G. The model is tested and a forecasting method suggested. Total productivity components are analysed and values for the productivity of various inputs during the period 1958-1980 given. Similarly, a model for representing safety, based on costs, is introduced, tested for accuracy and its components analysed. By applying marginal analysis to the total productivity and safety models, the influence of technological change on productivity and safety are quantified. It is concluded that a new method for measuring productivity should be adopted, in which case total productivity would be the most realistic and comprehensive choice. The models introduced can serve as useful tools in planning and forecasting, as well as being used to measure productivity and safety. Since this work has been in progress, work at the NCB has also led to consideration of improved measures of productivity

Use of Solution Strategy in Open Cast Mining Truck Dispatching System

The technique introduced in this paper is based on logical simulation and functional complex models, which will analyze, estimate and optimize the parameters of the open cast transportation system. For this purpose, flexible truck allocation has first been carried out by a goal programming model. The criteria to be optimized are maximization of production while controlling the quality of ore, which is sent to the processing plant. The transportation system has then been simulated by Arena simulator. This simulator and executive software has the advantages of schematic displacing of the real system. In this software, creating a mineral system perspective, determining the location of the equipments and their distances from each other is possible by using appropriate monitoring. The results of simulations have shown that using the proposed allocation technique, a substantial increase in production and productivity of an open cast mine is achieved